From e11c885d3412fa418524584e9d73de62e53ec01a Mon Sep 17 00:00:00 2001
From: yupix <yupi0982@outlook.jp>
Date: Mon, 18 May 2026 06:00:49 +0000
Subject: [PATCH 1/9] =?UTF-8?q?feat(backend):=20SMTP=E8=A8=AD=E5=AE=9A?=
 =?UTF-8?q?=E3=81=AE=E3=83=95=E3=82=A3=E3=83=BC=E3=83=AB=E3=83=89=E3=82=92?=
 =?UTF-8?q?=E8=BF=BD=E5=8A=A0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 apps/backend/src/settings.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/apps/backend/src/settings.rs b/apps/backend/src/settings.rs
index 1cd28bb..5b43243 100644
--- a/apps/backend/src/settings.rs
+++ b/apps/backend/src/settings.rs
@@ -8,6 +8,11 @@ pub struct Settings {
     pub sentry_dsn: Option<String>,
     #[serde(default = "default_allow_origin")]
     pub allow_origin: String,
+    pub smtp_server: String,
+    pub smtp_port: u16,
+    pub smtp_username: String,
+    pub smtp_password: String,
+    pub smtp_from: String,
 }
 
 fn default_allow_origin() -> String {

From 7cd2a698909240e9cd7fb9a1be80422fca7615e7 Mon Sep 17 00:00:00 2001
From: yupix <yupi0982@outlook.jp>
Date: Mon, 18 May 2026 06:01:36 +0000
Subject: [PATCH 2/9] =?UTF-8?q?feat(backend):=20SMTP=E9=80=81=E4=BF=A1?=
 =?UTF-8?q?=E7=94=A8=E3=81=ABlettre=E7=B3=BB=E3=81=AE=E3=82=AF=E3=83=AC?=
 =?UTF-8?q?=E3=83=BC=E3=83=88=E3=82=92=E4=BE=9D=E5=AD=98=E9=96=A2=E4=BF=82?=
 =?UTF-8?q?=E3=81=AB=E8=BF=BD=E5=8A=A0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 apps/backend/Cargo.lock | 535 ++++++++++++++++++++++++++++++++++------
 apps/backend/Cargo.toml |   2 +
 2 files changed, 468 insertions(+), 69 deletions(-)

diff --git a/apps/backend/Cargo.lock b/apps/backend/Cargo.lock
index 6ca10c8..f9acedc 100644
--- a/apps/backend/Cargo.lock
+++ b/apps/backend/Cargo.lock
@@ -8,7 +8,7 @@ version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5f7b0a21988c1bf877cf4759ef5ddaac04c1c9fe808c9142ecb78ba97d97a28a"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "bytes",
  "futures-core",
  "futures-sink",
@@ -29,7 +29,7 @@ dependencies = [
  "actix-rt",
  "actix-service",
  "actix-utils",
- "bitflags",
+ "bitflags 2.11.1",
  "bytes",
  "bytestring",
  "derive_more",
@@ -145,7 +145,7 @@ dependencies = [
  "serde_urlencoded",
  "smallvec",
  "socket2 0.6.3",
- "time",
+ "time 0.3.47",
  "tracing",
  "url",
 ]
@@ -208,7 +208,7 @@ checksum = "891477e0c6a8957309ee5c45a6368af3ae14bb510732d2684ffa19af310920f9"
 dependencies = [
  "getrandom 0.2.17",
  "once_cell",
- "version_check",
+ "version_check 0.9.5",
 ]
 
 [[package]]
@@ -221,7 +221,7 @@ dependencies = [
  "const-random",
  "getrandom 0.3.4",
  "once_cell",
- "version_check",
+ "version_check 0.9.5",
  "zerocopy",
 ]
 
@@ -366,7 +366,7 @@ dependencies = [
  "arrow-schema",
  "arrow-select",
  "atoi",
- "base64",
+ "base64 0.22.1",
  "chrono",
  "half",
  "lexical-core",
@@ -450,6 +450,12 @@ dependencies = [
  "regex-syntax",
 ]
 
+[[package]]
+name = "ascii_utils"
+version = "0.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "71938f30533e4d95a6d17aa530939da3842c2ab6f4f84b9dae68447e4129f74a"
+
 [[package]]
 name = "async-lock"
 version = "3.4.2"
@@ -509,6 +515,15 @@ version = "1.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1505bd5d3d116872e7271a6d4e16d81d0c8570876c8de68093a09ac269d8aac0"
 
+[[package]]
+name = "autocfg"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0dde43e75fd43e8a1bf86103336bc699aa8d17ad1be60c76c0bdfd4828e19b78"
+dependencies = [
+ "autocfg 1.5.0",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.5.0"
@@ -598,7 +613,7 @@ dependencies = [
  "aes-gcm",
  "async-trait",
  "axum",
- "base64",
+ "base64 0.22.1",
  "bytes",
  "chrono",
  "cookie",
@@ -617,7 +632,7 @@ dependencies = [
  "tower-layer",
  "tower-service",
  "tracing",
- "uuid",
+ "uuid 1.23.1",
 ]
 
 [[package]]
@@ -642,10 +657,12 @@ dependencies = [
  "axum-valid",
  "axum_session",
  "axum_session_redispool",
- "base64",
+ "base64 0.22.1",
  "config",
  "dotenvy",
  "hmac 0.13.0",
+ "lettre 0.11.22",
+ "lettre_email",
  "rand 0.10.1",
  "redis",
  "redis_pool",
@@ -666,7 +683,7 @@ dependencies = [
  "utoipa",
  "utoipa-axum",
  "utoipa-scalar",
- "uuid",
+ "uuid 1.23.1",
  "validator",
 ]
 
@@ -685,6 +702,25 @@ dependencies = [
  "windows-link",
 ]
 
+[[package]]
+name = "base64"
+version = "0.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "489d6c0ed21b11d038c31b6ceccca973e65d73ba3bd8ecb9a2babf5546164643"
+dependencies = [
+ "byteorder",
+ "safemem",
+]
+
+[[package]]
+name = "base64"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b25d992356d2eb0ed82172f5248873db5560c4721f564b13cb5193bda5e668e"
+dependencies = [
+ "byteorder",
+]
+
 [[package]]
 name = "base64"
 version = "0.22.1"
@@ -703,7 +739,7 @@ version = "0.4.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4d6867f1565b3aad85681f1015055b087fcfd840d6aeee6eee7f2da317603695"
 dependencies = [
- "autocfg",
+ "autocfg 1.5.0",
  "libm",
  "num-bigint",
  "num-integer",
@@ -711,6 +747,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
 [[package]]
 name = "bitflags"
 version = "2.11.1"
@@ -881,8 +923,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c673075a2e0e5f4a1dde27ce9dee1ea4558c7ffe648f576438a20ca1d2acc4b0"
 dependencies = [
  "iana-time-zone",
+ "js-sys",
  "num-traits",
  "serde",
+ "wasm-bindgen",
  "windows-link",
 ]
 
@@ -896,6 +940,15 @@ dependencies = [
  "inout",
 ]
 
+[[package]]
+name = "cloudabi"
+version = "0.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddfc5b9aa5d4507acaf872de71051dfd0e309860e88966e1051e462a077aac4f"
+dependencies = [
+ "bitflags 1.3.2",
+]
+
 [[package]]
 name = "cmov"
 version = "0.5.3"
@@ -1002,12 +1055,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4ddef33a339a91ea89fb53151bd0a4689cfce27055c291dfa69945475d22c747"
 dependencies = [
  "aes-gcm",
- "base64",
+ "base64 0.22.1",
  "percent-encoding",
  "rand 0.8.6",
  "subtle",
- "time",
- "version_check",
+ "time 0.3.47",
+ "version_check 0.9.5",
 ]
 
 [[package]]
@@ -1174,7 +1227,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef552e6f588e446098f6ba40d89ac146c8c7b64aade83c051ee00bb5d2bc18d"
 dependencies = [
  "serde",
- "uuid",
+ "uuid 1.23.1",
 ]
 
 [[package]]
@@ -1261,7 +1314,7 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1e0e367e4e7da84520dedcac1901e4da967309406d1e51017ae1abfb97adbd38"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "objc2",
 ]
 
@@ -1300,6 +1353,101 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "email"
+version = "0.0.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "91549a51bb0241165f13d57fc4c72cef063b4088fb078b019ecbf464a45f22e4"
+dependencies = [
+ "base64 0.9.3",
+ "chrono",
+ "encoding",
+ "lazy_static",
+ "rand 0.4.6",
+ "time 0.1.45",
+ "version_check 0.1.5",
+]
+
+[[package]]
+name = "email-encoding"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9298e6504d9b9e780ed3f7dfd43a61be8cd0e09eb07f7706a945b0072b6670b6"
+dependencies = [
+ "base64 0.22.1",
+ "memchr",
+]
+
+[[package]]
+name = "email_address"
+version = "0.2.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e079f19b08ca6239f47f8ba8509c11cf3ea30095831f7fed61441475edd8c449"
+
+[[package]]
+name = "encoding"
+version = "0.2.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6b0d943856b990d12d3b55b359144ff341533e516d94098b1d3fc1ac666d36ec"
+dependencies = [
+ "encoding-index-japanese",
+ "encoding-index-korean",
+ "encoding-index-simpchinese",
+ "encoding-index-singlebyte",
+ "encoding-index-tradchinese",
+]
+
+[[package]]
+name = "encoding-index-japanese"
+version = "1.20141219.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "04e8b2ff42e9a05335dbf8b5c6f7567e5591d0d916ccef4e0b1710d32a0d0c91"
+dependencies = [
+ "encoding_index_tests",
+]
+
+[[package]]
+name = "encoding-index-korean"
+version = "1.20141219.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4dc33fb8e6bcba213fe2f14275f0963fd16f0a02c878e3095ecfdf5bee529d81"
+dependencies = [
+ "encoding_index_tests",
+]
+
+[[package]]
+name = "encoding-index-simpchinese"
+version = "1.20141219.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d87a7194909b9118fc707194baa434a4e3b0fb6a5a757c73c3adb07aa25031f7"
+dependencies = [
+ "encoding_index_tests",
+]
+
+[[package]]
+name = "encoding-index-singlebyte"
+version = "1.20141219.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3351d5acffb224af9ca265f435b859c7c01537c0849754d3db3fdf2bfe2ae84a"
+dependencies = [
+ "encoding_index_tests",
+]
+
+[[package]]
+name = "encoding-index-tradchinese"
+version = "1.20141219.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fd0e20d5688ce3cab59eb3ef3a2083a5c77bf496cb798dc6fcdb75f323890c18"
+dependencies = [
+ "encoding_index_tests",
+]
+
+[[package]]
+name = "encoding_index_tests"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a246d82be1c9d791c5dfde9a2bd045fc3cbba3fa2b11ad558f27d01712f00569"
+
 [[package]]
 name = "encoding_rs"
 version = "0.8.35"
@@ -1368,6 +1516,15 @@ dependencies = [
  "pin-project-lite",
 ]
 
+[[package]]
+name = "fast_chemail"
+version = "0.9.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "495a39d30d624c2caabe6312bfead73e7717692b44e0b32df168c275a2e8e9e4"
+dependencies = [
+ "ascii_utils",
+]
+
 [[package]]
 name = "fastrand"
 version = "2.4.1"
@@ -1449,6 +1606,12 @@ dependencies = [
  "thiserror 1.0.69",
 ]
 
+[[package]]
+name = "fuchsia-cprng"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a06f77d526c1a601b7c4cdd98f54b5eaabffc14d5f2f0296febdc7f357c6d3ba"
+
 [[package]]
 name = "funty"
 version = "2.0.0"
@@ -1561,7 +1724,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "85649ca51fd72272d7821adaf274ad91c288277713d9c18820d8499a7ff69e9a"
 dependencies = [
  "typenum",
- "version_check",
+ "version_check 0.9.5",
 ]
 
 [[package]]
@@ -1572,7 +1735,7 @@ checksum = "ff2abc00be7fca6ebc474524697ae276ad847ad0a6b3faa4bcb027e9a4614ad0"
 dependencies = [
  "cfg-if",
  "libc",
- "wasi",
+ "wasi 0.11.1+wasi-snapshot-preview1",
 ]
 
 [[package]]
@@ -1884,7 +2047,7 @@ version = "0.1.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "96547c2556ec9d12fb1578c4eaf448b04993e7fb79cbaad930a656880a6bdfa0"
 dependencies = [
- "base64",
+ "base64 0.22.1",
  "bytes",
  "futures-channel",
  "futures-util",
@@ -2152,6 +2315,58 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "09edd9e8b54e49e587e4f6295a7d29c3ea94d469cb40ab8ca70b288248a81db2"
 
+[[package]]
+name = "lettre"
+version = "0.9.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "86ed8677138975b573ab4949c35613931a4addeadd0a8a6aa0327e2a979660de"
+dependencies = [
+ "fast_chemail",
+ "log",
+]
+
+[[package]]
+name = "lettre"
+version = "0.11.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0da65617f6cb926332d039cb578aad56178da86e128db6a1b09f4c94fa5b3349"
+dependencies = [
+ "async-trait",
+ "base64 0.22.1",
+ "email-encoding",
+ "email_address",
+ "fastrand",
+ "futures-io",
+ "futures-util",
+ "hostname",
+ "httpdate",
+ "idna",
+ "mime",
+ "nom",
+ "percent-encoding",
+ "quoted_printable",
+ "rustls",
+ "socket2 0.6.3",
+ "tokio",
+ "tokio-rustls",
+ "url",
+ "webpki-roots 1.0.7",
+]
+
+[[package]]
+name = "lettre_email"
+version = "0.9.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fd02480f8dcf48798e62113974d6ccca2129a51d241fa20f1ea349c8a42559d5"
+dependencies = [
+ "base64 0.10.1",
+ "email",
+ "lettre 0.9.6",
+ "mime",
+ "time 0.1.45",
+ "uuid 0.7.4",
+]
+
 [[package]]
 name = "lexical-core"
 version = "1.0.6"
@@ -2227,7 +2442,7 @@ version = "0.1.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e02f3bb43d335493c96bf3fd3a321600bf6bd07ed34bc64118e9293bdffea46c"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "libc",
  "plain",
  "redox_syscall 0.7.5",
@@ -2324,7 +2539,7 @@ version = "0.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "488016bfae457b036d996092f6cb448677611ce4449e970ceaf42695203f218a"
 dependencies = [
- "autocfg",
+ "autocfg 1.5.0",
 ]
 
 [[package]]
@@ -2350,7 +2565,7 @@ checksum = "50b7e5b27aa02a74bac8c3f23f448f8d87ff11f92d3aac1a6ed369ee08cc56c1"
 dependencies = [
  "libc",
  "log",
- "wasi",
+ "wasi 0.11.1+wasi-snapshot-preview1",
  "windows-sys 0.61.2",
 ]
 
@@ -2377,7 +2592,7 @@ version = "0.29.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "71e2746dc3a24dd78b3cfcb7be93368c6de9963d30f43a6a73998a9cf4b17b46"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "cfg-if",
  "cfg_aliases",
  "libc",
@@ -2390,12 +2605,21 @@ version = "0.30.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "74523f3a35e05aba87a1d978330aef40f67b0304ac79c1c00b294c9830543db6"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "cfg-if",
  "cfg_aliases",
  "libc",
 ]
 
+[[package]]
+name = "nom"
+version = "8.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df9761775871bdef83bee530e60050f7e54b1105350d6884eb0fb4f46c2f9405"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "nonempty"
 version = "0.7.0"
@@ -2467,7 +2691,7 @@ version = "0.1.45"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1429034a0490724d0075ebb2bc9e875d6503c3cf69e235a8941aa757d83ef5bf"
 dependencies = [
- "autocfg",
+ "autocfg 1.5.0",
  "num-integer",
  "num-traits",
 ]
@@ -2478,7 +2702,7 @@ version = "0.2.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
 dependencies = [
- "autocfg",
+ "autocfg 1.5.0",
  "libm",
 ]
 
@@ -2497,7 +2721,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "73ad74d880bb43877038da939b7427bba67e9dd42004a18b809ba7d87cee241c"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "objc2",
  "objc2-foundation",
 ]
@@ -2518,7 +2742,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2a180dd8642fa45cdb7dd721cd4c11b1cadd4929ce112ebd8b9f5803cc79d536"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "dispatch2",
  "objc2",
 ]
@@ -2529,7 +2753,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e022c9d066895efa1345f8e33e584b9f958da2fd4cd116792e15e07e4720a807"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "dispatch2",
  "objc2",
  "objc2-core-foundation",
@@ -2562,7 +2786,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0cde0dfb48d25d2b4862161a4d5fcc0e3c24367869ad306b0c9ec0073bfed92d"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "objc2",
  "objc2-core-foundation",
  "objc2-core-graphics",
@@ -2580,7 +2804,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e3e0adef53c21f888deb4fa59fc59f7eb17404926ee8a6f59f5df0fd7f9f3272"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "block2",
  "libc",
  "objc2",
@@ -2593,7 +2817,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "180788110936d59bab6bd83b6060ffdfffb3b922ba1396b312ae795e1de9d81d"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "objc2",
  "objc2-core-foundation",
 ]
@@ -2604,7 +2828,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "96c1358452b371bf9f104e21ec536d37a650eb10f7ee379fff67d2e08d537f1f"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "objc2",
  "objc2-core-foundation",
  "objc2-foundation",
@@ -2616,7 +2840,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d87d638e33c06f577498cbcc50491496a3ed4246998a7fbba7ccb98b1e7eab22"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "block2",
  "objc2",
  "objc2-cloud-kit",
@@ -2668,7 +2892,7 @@ version = "0.10.79"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bf0b434746ee2832f4f0baf10137e1cabb18cbe6912c69e2e33263c45250f542"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "cfg-if",
  "foreign-types",
  "libc",
@@ -3056,7 +3280,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "syn 2.0.117",
- "version_check",
+ "version_check 0.9.5",
  "yansi",
 ]
 
@@ -3089,6 +3313,12 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "quoted_printable"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "478e0585659a122aa407eb7e3c0e1fa51b1d8a870038bd29f0cf4a8551eea972"
+
 [[package]]
 name = "r-efi"
 version = "5.3.0"
@@ -3107,6 +3337,38 @@ version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dc33ff2d4973d518d823d61aa239014831e521c75da58e3df4840d3f47749d09"
 
+[[package]]
+name = "rand"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "552840b97013b1a26992c11eac34bdd778e464601a4c2054b5f0bff7c6761293"
+dependencies = [
+ "fuchsia-cprng",
+ "libc",
+ "rand_core 0.3.1",
+ "rdrand",
+ "winapi",
+]
+
+[[package]]
+name = "rand"
+version = "0.6.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6d71dacdc3c88c1fde3885a3be3fbab9f35724e6ce99467f7d9c5026132184ca"
+dependencies = [
+ "autocfg 0.1.8",
+ "libc",
+ "rand_chacha 0.1.1",
+ "rand_core 0.4.2",
+ "rand_hc",
+ "rand_isaac",
+ "rand_jitter",
+ "rand_os",
+ "rand_pcg",
+ "rand_xorshift",
+ "winapi",
+]
+
 [[package]]
 name = "rand"
 version = "0.8.6"
@@ -3139,6 +3401,16 @@ dependencies = [
  "rand_core 0.10.1",
 ]
 
+[[package]]
+name = "rand_chacha"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "556d3a1ca6600bfcbab7c7c91ccb085ac7fbbcd70e008a98742e7847f4f7bcef"
+dependencies = [
+ "autocfg 0.1.8",
+ "rand_core 0.3.1",
+]
+
 [[package]]
 name = "rand_chacha"
 version = "0.3.1"
@@ -3159,6 +3431,21 @@ dependencies = [
  "rand_core 0.9.5",
 ]
 
+[[package]]
+name = "rand_core"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a6fdeb83b075e8266dcc8762c22776f6877a63111121f5f8c7411e5be7eed4b"
+dependencies = [
+ "rand_core 0.4.2",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c33a3c44ca05fa6f1807d8e6743f3824e8509beca625669633be0acbdf509dc"
+
 [[package]]
 name = "rand_core"
 version = "0.6.4"
@@ -3183,6 +3470,77 @@ version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "63b8176103e19a2643978565ca18b50549f6101881c443590420e4dc998a3c69"
 
+[[package]]
+name = "rand_hc"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7b40677c7be09ae76218dc623efbf7b18e34bced3f38883af07bb75630a21bc4"
+dependencies = [
+ "rand_core 0.3.1",
+]
+
+[[package]]
+name = "rand_isaac"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ded997c9d5f13925be2a6fd7e66bf1872597f759fd9dd93513dd7e92e5a5ee08"
+dependencies = [
+ "rand_core 0.3.1",
+]
+
+[[package]]
+name = "rand_jitter"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1166d5c91dc97b88d1decc3285bb0a99ed84b05cfd0bc2341bdf2d43fc41e39b"
+dependencies = [
+ "libc",
+ "rand_core 0.4.2",
+ "winapi",
+]
+
+[[package]]
+name = "rand_os"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7b75f676a1e053fc562eafbb47838d67c84801e38fc1ba459e8f180deabd5071"
+dependencies = [
+ "cloudabi",
+ "fuchsia-cprng",
+ "libc",
+ "rand_core 0.4.2",
+ "rdrand",
+ "winapi",
+]
+
+[[package]]
+name = "rand_pcg"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "abf9b09b01790cfe0364f52bf32995ea3c39f4d2dd011eac241d2914146d0b44"
+dependencies = [
+ "autocfg 0.1.8",
+ "rand_core 0.4.2",
+]
+
+[[package]]
+name = "rand_xorshift"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cbf7e9e623549b0e21f6e97cf8ecf247c1a8fd2e8a992ae265314300b2455d5c"
+dependencies = [
+ "rand_core 0.3.1",
+]
+
+[[package]]
+name = "rdrand"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "678054eb77286b51581ba43620cc911abf02758c91f93f479767aed0f90458b2"
+dependencies = [
+ "rand_core 0.3.1",
+]
+
 [[package]]
 name = "redis"
 version = "1.2.1"
@@ -3229,7 +3587,7 @@ version = "0.5.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ed2bf2547551a7053d6fdfafda3f938979645c44812fbfcda098faae3f1a362d"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
 ]
 
 [[package]]
@@ -3238,7 +3596,7 @@ version = "0.7.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4666a1a60d8412eab19d94f6d13dcc9cea0a5ef4fdf6a5db306537413c661b1b"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
 ]
 
 [[package]]
@@ -3291,7 +3649,7 @@ version = "0.13.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "62e0021ea2c22aed41653bc7e1419abb2c97e038ff2c33d0e1309e49a97deec0"
 dependencies = [
- "base64",
+ "base64 0.22.1",
  "bytes",
  "futures-channel",
  "futures-core",
@@ -3353,7 +3711,7 @@ dependencies = [
  "rkyv_derive",
  "seahash",
  "tinyvec",
- "uuid",
+ "uuid 1.23.1",
 ]
 
 [[package]]
@@ -3373,7 +3731,7 @@ version = "0.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4147b952f3f819eca0e99527022f7d6a8d05f111aeb0a62960c74eb283bec8fc"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "once_cell",
  "serde",
  "serde_derive",
@@ -3449,7 +3807,7 @@ version = "1.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b6fe4565b9518b83ef4f91bb47ce29620ca828bd32cb7e408f0062e9930ba190"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "errno",
  "libc",
  "linux-raw-sys",
@@ -3462,6 +3820,7 @@ version = "0.23.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ef86cd5876211988985292b91c96a8f2d298df24e75989a43a3c73f2d4d8168b"
 dependencies = [
+ "log",
  "once_cell",
  "ring",
  "rustls-pki-types",
@@ -3502,6 +3861,12 @@ version = "1.0.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9774ba4a74de5f7b1c1451ed6cd5285a32eddb5cccb8cc655a4e50009e06477f"
 
+[[package]]
+name = "safemem"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef703b7cb59335eae2eb93ceb664c0eb7ea6bf567079d843e09420219668e072"
+
 [[package]]
 name = "schannel"
 version = "0.1.29"
@@ -3559,10 +3924,10 @@ dependencies = [
  "sqlx",
  "strum",
  "thiserror 2.0.18",
- "time",
+ "time 0.3.47",
  "tracing",
  "url",
- "uuid",
+ "uuid 1.23.1",
 ]
 
 [[package]]
@@ -3604,8 +3969,8 @@ dependencies = [
  "rust_decimal",
  "sea-query-derive",
  "serde_json",
- "time",
- "uuid",
+ "time 0.3.47",
+ "uuid 1.23.1",
 ]
 
 [[package]]
@@ -3669,7 +4034,7 @@ version = "3.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b7f4bc775c73d9a02cde8bf7b2ec4c9d12743edf609006c7facc23998404cd1d"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "core-foundation",
  "core-foundation-sys",
  "libc",
@@ -3806,7 +4171,7 @@ version = "0.48.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c51ec9620a4d398dcdf7ee90effbf8d8691cfa24e91978bfa8565cac039d4980"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "sentry-backtrace",
  "sentry-core",
  "tracing-core",
@@ -3825,9 +4190,9 @@ dependencies = [
  "serde",
  "serde_json",
  "thiserror 2.0.18",
- "time",
+ "time 0.3.47",
  "url",
- "uuid",
+ "uuid 1.23.1",
 ]
 
 [[package]]
@@ -4070,7 +4435,7 @@ version = "0.8.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ee6798b1838b6a0f69c007c133b8df5866302197e404e8b6ee8ed3e3a5e68dc6"
 dependencies = [
- "base64",
+ "base64 0.22.1",
  "bytes",
  "chrono",
  "crc",
@@ -4095,12 +4460,12 @@ dependencies = [
  "sha2 0.10.9",
  "smallvec",
  "thiserror 2.0.18",
- "time",
+ "time 0.3.47",
  "tokio",
  "tokio-stream",
  "tracing",
  "url",
- "uuid",
+ "uuid 1.23.1",
  "webpki-roots 0.26.11",
 ]
 
@@ -4149,8 +4514,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "aa003f0038df784eb8fecbbac13affe3da23b45194bd57dba231c8f48199c526"
 dependencies = [
  "atoi",
- "base64",
- "bitflags",
+ "base64 0.22.1",
+ "bitflags 2.11.1",
  "byteorder",
  "bytes",
  "chrono",
@@ -4182,9 +4547,9 @@ dependencies = [
  "sqlx-core",
  "stringprep",
  "thiserror 2.0.18",
- "time",
+ "time 0.3.47",
  "tracing",
- "uuid",
+ "uuid 1.23.1",
  "whoami",
 ]
 
@@ -4195,8 +4560,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "db58fcd5a53cf07c184b154801ff91347e4c30d17a3562a635ff028ad5deda46"
 dependencies = [
  "atoi",
- "base64",
- "bitflags",
+ "base64 0.22.1",
+ "bitflags 2.11.1",
  "byteorder",
  "chrono",
  "crc",
@@ -4223,9 +4588,9 @@ dependencies = [
  "sqlx-core",
  "stringprep",
  "thiserror 2.0.18",
- "time",
+ "time 0.3.47",
  "tracing",
- "uuid",
+ "uuid 1.23.1",
  "whoami",
 ]
 
@@ -4250,10 +4615,10 @@ dependencies = [
  "serde_urlencoded",
  "sqlx-core",
  "thiserror 2.0.18",
- "time",
+ "time 0.3.47",
  "tracing",
  "url",
- "uuid",
+ "uuid 1.23.1",
 ]
 
 [[package]]
@@ -4422,6 +4787,17 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "time"
+version = "0.1.45"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b797afad3f312d1c66a56d11d0316f916356d11bd158fbc6ca6389ff6bf805a"
+dependencies = [
+ "libc",
+ "wasi 0.10.0+wasi-snapshot-preview1",
+ "winapi",
+]
+
 [[package]]
 name = "time"
 version = "0.3.47"
@@ -4624,7 +5000,7 @@ version = "0.6.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "68d6fdd9f81c2819c9a8b0e0cd91660e7746a8e6ea2ba7c6b2b057985f6bcb51"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "bytes",
  "futures-util",
  "http 1.4.0",
@@ -4804,7 +5180,7 @@ version = "3.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dea7109cdcd5864d4eeb1b58a1648dc9bf520360d7af16ec26d0a9354bafcfc0"
 dependencies = [
- "base64",
+ "base64 0.22.1",
  "der 0.8.0",
  "log",
  "native-tls",
@@ -4821,7 +5197,7 @@ version = "0.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e994ba84b0bd1b1b0cf92878b7ef898a5c1760108fe7b6010327e274917a808c"
 dependencies = [
- "base64",
+ "base64 0.22.1",
  "http 1.4.0",
  "httparse",
  "log",
@@ -4886,7 +5262,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "syn 2.0.117",
- "uuid",
+ "uuid 1.23.1",
 ]
 
 [[package]]
@@ -4901,6 +5277,15 @@ dependencies = [
  "utoipa",
 ]
 
+[[package]]
+name = "uuid"
+version = "0.7.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90dbc611eb48397705a6b0f6e917da23ae517e4d127123d2cf7674206627d32a"
+dependencies = [
+ "rand 0.6.5",
+]
+
 [[package]]
 name = "uuid"
 version = "1.23.1"
@@ -4955,6 +5340,12 @@ version = "0.2.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "accd4ea62f7bb7a82fe23066fb0957d48ef677f6eeb8215f372f52e48bb32426"
 
+[[package]]
+name = "version_check"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "914b1a6776c4c929a602fafd8bc742e06365d4bcbe48c30f9cca5824f70dc9dd"
+
 [[package]]
 name = "version_check"
 version = "0.9.5"
@@ -4970,6 +5361,12 @@ dependencies = [
  "try-lock",
 ]
 
+[[package]]
+name = "wasi"
+version = "0.10.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1a143597ca7c7793eff794def352d41792a93c481eb1042423ff7ff72ba2c31f"
+
 [[package]]
 name = "wasi"
 version = "0.11.1+wasi-snapshot-preview1"
@@ -5084,7 +5481,7 @@ version = "0.244.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "47b807c72e1bac69382b3a6fb3dbe8ea4c0ed87ff5629b8685ae6b9a611028fe"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.1",
  "hashbrown 0.15.5",
  "indexmap",
  "semver",
@@ -5439,7 +5836,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9d66ea20e9553b30172b5e831994e35fbde2d165325bec84fc43dbf6f4eb9cb2"
 dependencies = [
  "anyhow",
- "bitflags",
+ "bitflags 2.11.1",
  "indexmap",
  "log",
  "serde",
diff --git a/apps/backend/Cargo.toml b/apps/backend/Cargo.toml
index 3b9ed6e..daa38f2 100644
--- a/apps/backend/Cargo.toml
+++ b/apps/backend/Cargo.toml
@@ -44,3 +44,5 @@ rand = "0.10"
 subtle = "2.4"
 strum = { version = "0.28.0", features = ["derive"] }
 strum_macros = "0.28"
+lettre = { version = "0.11", default-features = false, features = ["builder", "hostname", "smtp-transport","tokio1", "tokio1-rustls-tls"] }
+lettre_email = "0.9"
\ No newline at end of file

From c82e676be0ec575a157011c325e4a0b8b1fc760d Mon Sep 17 00:00:00 2001
From: yupix <yupi0982@outlook.jp>
Date: Mon, 18 May 2026 06:05:01 +0000
Subject: [PATCH 3/9] =?UTF-8?q?feat(backend):=20SMTP=E3=82=AF=E3=83=A9?=
 =?UTF-8?q?=E3=82=A4=E3=82=A2=E3=83=B3=E3=83=88=E3=81=AE=E8=BF=BD=E5=8A=A0?=
 =?UTF-8?q?=E3=81=A8=E8=A8=AD=E5=AE=9A=E3=83=95=E3=82=A3=E3=83=BC=E3=83=AB?=
 =?UTF-8?q?=E3=83=89=E3=81=AE=E4=BF=AE=E6=AD=A3?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 apps/backend/src/lib.rs        |  3 +-
 apps/backend/src/settings.rs   |  2 +-
 apps/backend/src/utils/mod.rs  |  1 +
 apps/backend/src/utils/smtp.rs | 92 ++++++++++++++++++++++++++++++++++
 4 files changed, 96 insertions(+), 2 deletions(-)
 create mode 100644 apps/backend/src/utils/smtp.rs

diff --git a/apps/backend/src/lib.rs b/apps/backend/src/lib.rs
index cd858b6..52ae936 100644
--- a/apps/backend/src/lib.rs
+++ b/apps/backend/src/lib.rs
@@ -1,4 +1,4 @@
-use crate::{settings::Settings, utils::redis::RedisConnection};
+use crate::{settings::Settings, utils::{redis::RedisConnection, smtp::SmtpClient}};
 use sea_orm::DatabaseConnection;
 
 pub mod dto;
@@ -17,4 +17,5 @@ pub struct AppState {
     pub settings: Settings,
     pub db: DatabaseConnection,
     pub redis_client: RedisConnection,
+    pub smtp_client: SmtpClient
 }
diff --git a/apps/backend/src/settings.rs b/apps/backend/src/settings.rs
index 5b43243..720d1dc 100644
--- a/apps/backend/src/settings.rs
+++ b/apps/backend/src/settings.rs
@@ -8,7 +8,7 @@ pub struct Settings {
     pub sentry_dsn: Option<String>,
     #[serde(default = "default_allow_origin")]
     pub allow_origin: String,
-    pub smtp_server: String,
+    pub smtp_host: String,
     pub smtp_port: u16,
     pub smtp_username: String,
     pub smtp_password: String,
diff --git a/apps/backend/src/utils/mod.rs b/apps/backend/src/utils/mod.rs
index ecfb340..99be336 100644
--- a/apps/backend/src/utils/mod.rs
+++ b/apps/backend/src/utils/mod.rs
@@ -1,2 +1,3 @@
 pub mod auth;
 pub mod redis;
+pub mod smtp;
diff --git a/apps/backend/src/utils/smtp.rs b/apps/backend/src/utils/smtp.rs
new file mode 100644
index 0000000..34810ce
--- /dev/null
+++ b/apps/backend/src/utils/smtp.rs
@@ -0,0 +1,92 @@
+/// SMTPクライアントを提供するモジュール
+
+use lettre::message::{Mailbox, Message, MultiPart, SinglePart};
+use lettre::{AsyncSmtpTransport, AsyncTransport, transport::smtp::authentication::Credentials};
+use lettre::Tokio1Executor;
+
+/// SMTPクライアントの構造体
+#[derive(Clone, Debug)]
+pub struct SmtpClient {
+    mailer: AsyncSmtpTransport<Tokio1Executor>,
+}
+
+/// SmtpClientの実装
+impl SmtpClient {
+    /// 新しいSMTPクライアントを作成する関数
+    /// 
+    /// # Arguments
+    /// * `smtp_server` - SMTPサーバーのアドレス
+    /// * `smtp_port` - SMTPサーバーのポート番号
+    /// * `username` - SMTPサーバーの認証に使用するユーザー名
+    /// * `password` - SMTPサーバーの認証に使用するパスワード
+    /// 
+    ///  # Examples
+    /// 
+    ///  ```
+    /// let smtp_client = SmtpClient::new("smtp.example.com", 587, "user", "pass").unwrap();
+    /// ```
+    pub fn new(
+        smtp_server: &str, 
+        smtp_port: u16, 
+        username: &str, 
+        password: &str
+    ) -> Result<Self, lettre::transport::smtp::Error> {
+        let creds = Credentials::new(username.to_string(), password.to_string());
+        
+        let mailer = AsyncSmtpTransport::<Tokio1Executor>::starttls_relay(smtp_server)?
+            .port(smtp_port)
+            .credentials(creds)
+            .build();
+            
+        Ok(SmtpClient { mailer })
+    }
+
+    /// メールを送信する関数
+    /// 
+    /// # Arguments
+    /// * `from` - 送信元のメールアドレス
+    /// * `to` - 送信先のメールアドレス
+    /// * `subject` - メールの件名
+    /// * `body_text` - メールのテキスト形式の本文
+    /// * `body_html` - メールのHTML形式の本文（オプション）
+    /// 
+    /// # Examples
+    /// 
+    /// ```
+    ///client.send_email(
+    ///    "sender@example.com",
+    ///    "receiver@example.com",
+    ///    "Hello from Async Rust!",
+    ///    "This is a test email sent asynchronously.",
+    ///    Some("<p>This is a <b>test</b> email sent asynchronously.</p>"),
+    ///).await?;
+    /// ```
+    /// 
+    pub async fn send_email(
+        &self,
+        from: &str,
+        to: &str,
+        subject: &str,
+        body_text: &str,
+        body_html: Option<&str>,
+    ) -> Result<(), Box<dyn std::error::Error>> {
+        
+        let builder = Message::builder()
+            .from(from.parse::<Mailbox>()?)
+            .to(to.parse::<Mailbox>()?)
+            .subject(subject);
+
+        let email = match body_html {
+            Some(html) => builder.multipart(
+                MultiPart::alternative()
+                    .singlepart(SinglePart::plain(body_text.to_string()))
+                    .singlepart(SinglePart::html(html.to_string())),
+            )?,
+            None => builder.singlepart(SinglePart::plain(body_text.to_string()))?,
+        };
+
+        self.mailer.send(email).await?;
+        
+        Ok(())
+    }
+}
\ No newline at end of file

From dff13b200a126e635bb4c4ec62bb554bffa1ad4e Mon Sep 17 00:00:00 2001
From: yupix <yupi0982@outlook.jp>
Date: Mon, 18 May 2026 06:05:21 +0000
Subject: [PATCH 4/9] =?UTF-8?q?feat(backend):=20SMTP=E3=82=AF=E3=83=A9?=
 =?UTF-8?q?=E3=82=A4=E3=82=A2=E3=83=B3=E3=83=88=E3=82=92AppState=E3=81=AB?=
 =?UTF-8?q?=E6=B8=A1=E3=81=99=E3=82=88=E3=81=86=E3=81=AB?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 apps/backend/src/main.rs | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/apps/backend/src/main.rs b/apps/backend/src/main.rs
index 8679b38..a77663a 100644
--- a/apps/backend/src/main.rs
+++ b/apps/backend/src/main.rs
@@ -1,4 +1,4 @@
-use backend::{AppState, server::run};
+use backend::{AppState, server::run, utils::smtp::SmtpClient};
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
@@ -19,12 +19,19 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         .sync(&db)
         .await?;
 
+    let smtp_client = SmtpClient::new(
+        &settings.smtp_host,
+        settings.smtp_port,
+        &settings.smtp_username,
+        &settings.smtp_password,
+    )?;
     let redis_client = backend::utils::redis::RedisConnection::new(&settings.redis_url);
     redis_client.ping().await?;
     let state = AppState {
         settings,
         db,
         redis_client,
+        smtp_client,
     };
     run(state).await?;
 

From 394182c94ddb219c6cfea876ff921bacdc8f7e11 Mon Sep 17 00:00:00 2001
From: yupix <yupi0982@outlook.jp>
Date: Mon, 18 May 2026 06:09:01 +0000
Subject: [PATCH 5/9] =?UTF-8?q?chore(backend):=20.env.example=E3=81=ABSMTP?=
 =?UTF-8?q?=E9=96=A2=E4=BF=82=E3=81=AE=E4=BE=8B=E3=82=92=E8=BF=BD=E5=8A=A0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 apps/backend/.env.example | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/apps/backend/.env.example b/apps/backend/.env.example
index e927dd0..b2afe8a 100644
--- a/apps/backend/.env.example
+++ b/apps/backend/.env.example
@@ -1,3 +1,8 @@
 database_url=postgresql://username:password@host:port/db_name
 redis_url=redis://127.0.0.1:6379
 sentry_dsn=
+smtp_host=smtp.example.com
+smtp_port=587
+smtp_username=your_smtp_username
+smtp_password=your_smtp_password
+smtp_from=no-reply@example.com

From e355257acc8a4de181dd4731e3fbdf5c75012d21 Mon Sep 17 00:00:00 2001
From: yupix <yupi0982@outlook.jp>
Date: Mon, 18 May 2026 06:22:31 +0000
Subject: [PATCH 6/9] =?UTF-8?q?fix(backend):=20doctest=E3=81=8C=E8=90=BD?=
 =?UTF-8?q?=E3=81=A1=E3=82=8B?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 apps/backend/src/utils/smtp.rs | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/apps/backend/src/utils/smtp.rs b/apps/backend/src/utils/smtp.rs
index 34810ce..3ca8db2 100644
--- a/apps/backend/src/utils/smtp.rs
+++ b/apps/backend/src/utils/smtp.rs
@@ -22,7 +22,9 @@ impl SmtpClient {
     /// 
     ///  # Examples
     /// 
-    ///  ```
+    ///  ```no_run
+    /// use backend::utils::smtp::SmtpClient;
+    ///
     /// let smtp_client = SmtpClient::new("smtp.example.com", 587, "user", "pass").unwrap();
     /// ```
     pub fn new(
@@ -52,16 +54,22 @@ impl SmtpClient {
     /// 
     /// # Examples
     /// 
+    /// ```no_run
+    /// use backend::utils::smtp::SmtpClient;
+    ///
+    /// # #[tokio::main]
+    /// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    /// let client = SmtpClient::new("smtp.example.com", 587, "user", "pass")?;
+    /// client.send_email(
+    ///     "sender@example.com",
+    ///     "receiver@example.com",
+    ///     "Hello from Async Rust!",
+    ///     "This is a test email sent asynchronously.",
+    ///     Some("<p>This is a <b>test</b> email sent asynchronously.</p>"),
+    /// ).await?;
+    /// # Ok(())
+    /// # }
     /// ```
-    ///client.send_email(
-    ///    "sender@example.com",
-    ///    "receiver@example.com",
-    ///    "Hello from Async Rust!",
-    ///    "This is a test email sent asynchronously.",
-    ///    Some("<p>This is a <b>test</b> email sent asynchronously.</p>"),
-    ///).await?;
-    /// ```
-    /// 
     pub async fn send_email(
         &self,
         from: &str,

From 922adb1e065be0145165a40371a4498e11b04b02 Mon Sep 17 00:00:00 2001
From: yupix <yupi0982@outlook.jp>
Date: Mon, 18 May 2026 06:25:51 +0000
Subject: [PATCH 7/9] =?UTF-8?q?feat(backend):=20SMTP=E9=80=81=E4=BF=A1?=
 =?UTF-8?q?=E5=87=A6=E7=90=86=E3=81=AB30=E7=A7=92=E3=81=AE=E3=82=BF?=
 =?UTF-8?q?=E3=82=A4=E3=83=A0=E3=82=A2=E3=82=A6=E3=83=88=E3=82=92=E8=BF=BD?=
 =?UTF-8?q?=E5=8A=A0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 apps/backend/src/utils/smtp.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/apps/backend/src/utils/smtp.rs b/apps/backend/src/utils/smtp.rs
index 3ca8db2..5f9154d 100644
--- a/apps/backend/src/utils/smtp.rs
+++ b/apps/backend/src/utils/smtp.rs
@@ -1,8 +1,11 @@
+use std::time::Duration;
+
 /// SMTPクライアントを提供するモジュール
 
 use lettre::message::{Mailbox, Message, MultiPart, SinglePart};
 use lettre::{AsyncSmtpTransport, AsyncTransport, transport::smtp::authentication::Credentials};
 use lettre::Tokio1Executor;
+use tokio::time::timeout;
 
 /// SMTPクライアントの構造体
 #[derive(Clone, Debug)]
@@ -93,7 +96,10 @@ impl SmtpClient {
             None => builder.singlepart(SinglePart::plain(body_text.to_string()))?,
         };
 
-        self.mailer.send(email).await?;
+        // 送信処理にタイムアウトを30秒に設定
+        let _ = timeout(Duration::from_secs(30), self.mailer.send(email))
+            .await
+            .map_err(|_| "SMTP send timeout")?;
         
         Ok(())
     }

From f3f7cc24b7ab6f5f4bd87f6f917e60cf4f723100 Mon Sep 17 00:00:00 2001
From: yupix <yupi0982@outlook.jp>
Date: Mon, 18 May 2026 06:37:48 +0000
Subject: [PATCH 8/9] =?UTF-8?q?fix(backend):=20SMTP=E3=82=AF=E3=83=A9?=
 =?UTF-8?q?=E3=82=A4=E3=82=A2=E3=83=B3=E3=83=88=E3=81=AE=E5=88=9D=E6=9C=9F?=
 =?UTF-8?q?=E5=8C=96=E3=82=A8=E3=83=A9=E3=83=BC=E3=83=8F=E3=83=B3=E3=83=89?=
 =?UTF-8?q?=E3=83=AA=E3=83=B3=E3=82=B0=E3=82=92=E6=94=B9=E5=96=84=E3=81=97?=
 =?UTF-8?q?=E3=80=81=E4=B8=8D=E8=A6=81=E3=81=AA=E4=BE=9D=E5=AD=98=E9=96=A2?=
 =?UTF-8?q?=E4=BF=82=E3=82=92=E5=89=8A=E9=99=A4?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 apps/backend/Cargo.lock        | 480 +++++----------------------------
 apps/backend/Cargo.toml        |   1 -
 apps/backend/src/lib.rs        |   7 +-
 apps/backend/src/main.rs       |   7 +-
 apps/backend/src/utils/auth.rs |   5 +-
 apps/backend/src/utils/smtp.rs |  50 ++--
 6 files changed, 114 insertions(+), 436 deletions(-)

diff --git a/apps/backend/Cargo.lock b/apps/backend/Cargo.lock
index f9acedc..25ff67d 100644
--- a/apps/backend/Cargo.lock
+++ b/apps/backend/Cargo.lock
@@ -8,7 +8,7 @@ version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5f7b0a21988c1bf877cf4759ef5ddaac04c1c9fe808c9142ecb78ba97d97a28a"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "bytes",
  "futures-core",
  "futures-sink",
@@ -29,7 +29,7 @@ dependencies = [
  "actix-rt",
  "actix-service",
  "actix-utils",
- "bitflags 2.11.1",
+ "bitflags",
  "bytes",
  "bytestring",
  "derive_more",
@@ -145,7 +145,7 @@ dependencies = [
  "serde_urlencoded",
  "smallvec",
  "socket2 0.6.3",
- "time 0.3.47",
+ "time",
  "tracing",
  "url",
 ]
@@ -208,7 +208,7 @@ checksum = "891477e0c6a8957309ee5c45a6368af3ae14bb510732d2684ffa19af310920f9"
 dependencies = [
  "getrandom 0.2.17",
  "once_cell",
- "version_check 0.9.5",
+ "version_check",
 ]
 
 [[package]]
@@ -221,7 +221,7 @@ dependencies = [
  "const-random",
  "getrandom 0.3.4",
  "once_cell",
- "version_check 0.9.5",
+ "version_check",
  "zerocopy",
 ]
 
@@ -366,7 +366,7 @@ dependencies = [
  "arrow-schema",
  "arrow-select",
  "atoi",
- "base64 0.22.1",
+ "base64",
  "chrono",
  "half",
  "lexical-core",
@@ -450,12 +450,6 @@ dependencies = [
  "regex-syntax",
 ]
 
-[[package]]
-name = "ascii_utils"
-version = "0.9.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "71938f30533e4d95a6d17aa530939da3842c2ab6f4f84b9dae68447e4129f74a"
-
 [[package]]
 name = "async-lock"
 version = "3.4.2"
@@ -515,15 +509,6 @@ version = "1.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1505bd5d3d116872e7271a6d4e16d81d0c8570876c8de68093a09ac269d8aac0"
 
-[[package]]
-name = "autocfg"
-version = "0.1.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0dde43e75fd43e8a1bf86103336bc699aa8d17ad1be60c76c0bdfd4828e19b78"
-dependencies = [
- "autocfg 1.5.0",
-]
-
 [[package]]
 name = "autocfg"
 version = "1.5.0"
@@ -613,7 +598,7 @@ dependencies = [
  "aes-gcm",
  "async-trait",
  "axum",
- "base64 0.22.1",
+ "base64",
  "bytes",
  "chrono",
  "cookie",
@@ -632,7 +617,7 @@ dependencies = [
  "tower-layer",
  "tower-service",
  "tracing",
- "uuid 1.23.1",
+ "uuid",
 ]
 
 [[package]]
@@ -657,12 +642,11 @@ dependencies = [
  "axum-valid",
  "axum_session",
  "axum_session_redispool",
- "base64 0.22.1",
+ "base64",
  "config",
  "dotenvy",
  "hmac 0.13.0",
- "lettre 0.11.22",
- "lettre_email",
+ "lettre",
  "rand 0.10.1",
  "redis",
  "redis_pool",
@@ -683,7 +667,7 @@ dependencies = [
  "utoipa",
  "utoipa-axum",
  "utoipa-scalar",
- "uuid 1.23.1",
+ "uuid",
  "validator",
 ]
 
@@ -702,25 +686,6 @@ dependencies = [
  "windows-link",
 ]
 
-[[package]]
-name = "base64"
-version = "0.9.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "489d6c0ed21b11d038c31b6ceccca973e65d73ba3bd8ecb9a2babf5546164643"
-dependencies = [
- "byteorder",
- "safemem",
-]
-
-[[package]]
-name = "base64"
-version = "0.10.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0b25d992356d2eb0ed82172f5248873db5560c4721f564b13cb5193bda5e668e"
-dependencies = [
- "byteorder",
-]
-
 [[package]]
 name = "base64"
 version = "0.22.1"
@@ -739,7 +704,7 @@ version = "0.4.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4d6867f1565b3aad85681f1015055b087fcfd840d6aeee6eee7f2da317603695"
 dependencies = [
- "autocfg 1.5.0",
+ "autocfg",
  "libm",
  "num-bigint",
  "num-integer",
@@ -747,12 +712,6 @@ dependencies = [
  "serde",
 ]
 
-[[package]]
-name = "bitflags"
-version = "1.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
-
 [[package]]
 name = "bitflags"
 version = "2.11.1"
@@ -923,10 +882,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c673075a2e0e5f4a1dde27ce9dee1ea4558c7ffe648f576438a20ca1d2acc4b0"
 dependencies = [
  "iana-time-zone",
- "js-sys",
  "num-traits",
  "serde",
- "wasm-bindgen",
  "windows-link",
 ]
 
@@ -940,15 +897,6 @@ dependencies = [
  "inout",
 ]
 
-[[package]]
-name = "cloudabi"
-version = "0.0.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ddfc5b9aa5d4507acaf872de71051dfd0e309860e88966e1051e462a077aac4f"
-dependencies = [
- "bitflags 1.3.2",
-]
-
 [[package]]
 name = "cmov"
 version = "0.5.3"
@@ -1055,12 +1003,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4ddef33a339a91ea89fb53151bd0a4689cfce27055c291dfa69945475d22c747"
 dependencies = [
  "aes-gcm",
- "base64 0.22.1",
+ "base64",
  "percent-encoding",
  "rand 0.8.6",
  "subtle",
- "time 0.3.47",
- "version_check 0.9.5",
+ "time",
+ "version_check",
 ]
 
 [[package]]
@@ -1227,7 +1175,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef552e6f588e446098f6ba40d89ac146c8c7b64aade83c051ee00bb5d2bc18d"
 dependencies = [
  "serde",
- "uuid 1.23.1",
+ "uuid",
 ]
 
 [[package]]
@@ -1314,7 +1262,7 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1e0e367e4e7da84520dedcac1901e4da967309406d1e51017ae1abfb97adbd38"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "objc2",
 ]
 
@@ -1353,28 +1301,13 @@ dependencies = [
  "serde",
 ]
 
-[[package]]
-name = "email"
-version = "0.0.20"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "91549a51bb0241165f13d57fc4c72cef063b4088fb078b019ecbf464a45f22e4"
-dependencies = [
- "base64 0.9.3",
- "chrono",
- "encoding",
- "lazy_static",
- "rand 0.4.6",
- "time 0.1.45",
- "version_check 0.1.5",
-]
-
 [[package]]
 name = "email-encoding"
 version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9298e6504d9b9e780ed3f7dfd43a61be8cd0e09eb07f7706a945b0072b6670b6"
 dependencies = [
- "base64 0.22.1",
+ "base64",
  "memchr",
 ]
 
@@ -1384,70 +1317,6 @@ version = "0.2.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e079f19b08ca6239f47f8ba8509c11cf3ea30095831f7fed61441475edd8c449"
 
-[[package]]
-name = "encoding"
-version = "0.2.33"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6b0d943856b990d12d3b55b359144ff341533e516d94098b1d3fc1ac666d36ec"
-dependencies = [
- "encoding-index-japanese",
- "encoding-index-korean",
- "encoding-index-simpchinese",
- "encoding-index-singlebyte",
- "encoding-index-tradchinese",
-]
-
-[[package]]
-name = "encoding-index-japanese"
-version = "1.20141219.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "04e8b2ff42e9a05335dbf8b5c6f7567e5591d0d916ccef4e0b1710d32a0d0c91"
-dependencies = [
- "encoding_index_tests",
-]
-
-[[package]]
-name = "encoding-index-korean"
-version = "1.20141219.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4dc33fb8e6bcba213fe2f14275f0963fd16f0a02c878e3095ecfdf5bee529d81"
-dependencies = [
- "encoding_index_tests",
-]
-
-[[package]]
-name = "encoding-index-simpchinese"
-version = "1.20141219.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d87a7194909b9118fc707194baa434a4e3b0fb6a5a757c73c3adb07aa25031f7"
-dependencies = [
- "encoding_index_tests",
-]
-
-[[package]]
-name = "encoding-index-singlebyte"
-version = "1.20141219.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3351d5acffb224af9ca265f435b859c7c01537c0849754d3db3fdf2bfe2ae84a"
-dependencies = [
- "encoding_index_tests",
-]
-
-[[package]]
-name = "encoding-index-tradchinese"
-version = "1.20141219.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fd0e20d5688ce3cab59eb3ef3a2083a5c77bf496cb798dc6fcdb75f323890c18"
-dependencies = [
- "encoding_index_tests",
-]
-
-[[package]]
-name = "encoding_index_tests"
-version = "0.1.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a246d82be1c9d791c5dfde9a2bd045fc3cbba3fa2b11ad558f27d01712f00569"
-
 [[package]]
 name = "encoding_rs"
 version = "0.8.35"
@@ -1516,15 +1385,6 @@ dependencies = [
  "pin-project-lite",
 ]
 
-[[package]]
-name = "fast_chemail"
-version = "0.9.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "495a39d30d624c2caabe6312bfead73e7717692b44e0b32df168c275a2e8e9e4"
-dependencies = [
- "ascii_utils",
-]
-
 [[package]]
 name = "fastrand"
 version = "2.4.1"
@@ -1606,12 +1466,6 @@ dependencies = [
  "thiserror 1.0.69",
 ]
 
-[[package]]
-name = "fuchsia-cprng"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a06f77d526c1a601b7c4cdd98f54b5eaabffc14d5f2f0296febdc7f357c6d3ba"
-
 [[package]]
 name = "funty"
 version = "2.0.0"
@@ -1724,7 +1578,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "85649ca51fd72272d7821adaf274ad91c288277713d9c18820d8499a7ff69e9a"
 dependencies = [
  "typenum",
- "version_check 0.9.5",
+ "version_check",
 ]
 
 [[package]]
@@ -1735,7 +1589,7 @@ checksum = "ff2abc00be7fca6ebc474524697ae276ad847ad0a6b3faa4bcb027e9a4614ad0"
 dependencies = [
  "cfg-if",
  "libc",
- "wasi 0.11.1+wasi-snapshot-preview1",
+ "wasi",
 ]
 
 [[package]]
@@ -2047,7 +1901,7 @@ version = "0.1.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "96547c2556ec9d12fb1578c4eaf448b04993e7fb79cbaad930a656880a6bdfa0"
 dependencies = [
- "base64 0.22.1",
+ "base64",
  "bytes",
  "futures-channel",
  "futures-util",
@@ -2315,16 +2169,6 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "09edd9e8b54e49e587e4f6295a7d29c3ea94d469cb40ab8ca70b288248a81db2"
 
-[[package]]
-name = "lettre"
-version = "0.9.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "86ed8677138975b573ab4949c35613931a4addeadd0a8a6aa0327e2a979660de"
-dependencies = [
- "fast_chemail",
- "log",
-]
-
 [[package]]
 name = "lettre"
 version = "0.11.22"
@@ -2332,7 +2176,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0da65617f6cb926332d039cb578aad56178da86e128db6a1b09f4c94fa5b3349"
 dependencies = [
  "async-trait",
- "base64 0.22.1",
+ "base64",
  "email-encoding",
  "email_address",
  "fastrand",
@@ -2353,20 +2197,6 @@ dependencies = [
  "webpki-roots 1.0.7",
 ]
 
-[[package]]
-name = "lettre_email"
-version = "0.9.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fd02480f8dcf48798e62113974d6ccca2129a51d241fa20f1ea349c8a42559d5"
-dependencies = [
- "base64 0.10.1",
- "email",
- "lettre 0.9.6",
- "mime",
- "time 0.1.45",
- "uuid 0.7.4",
-]
-
 [[package]]
 name = "lexical-core"
 version = "1.0.6"
@@ -2442,7 +2272,7 @@ version = "0.1.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e02f3bb43d335493c96bf3fd3a321600bf6bd07ed34bc64118e9293bdffea46c"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "libc",
  "plain",
  "redox_syscall 0.7.5",
@@ -2539,7 +2369,7 @@ version = "0.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "488016bfae457b036d996092f6cb448677611ce4449e970ceaf42695203f218a"
 dependencies = [
- "autocfg 1.5.0",
+ "autocfg",
 ]
 
 [[package]]
@@ -2565,7 +2395,7 @@ checksum = "50b7e5b27aa02a74bac8c3f23f448f8d87ff11f92d3aac1a6ed369ee08cc56c1"
 dependencies = [
  "libc",
  "log",
- "wasi 0.11.1+wasi-snapshot-preview1",
+ "wasi",
  "windows-sys 0.61.2",
 ]
 
@@ -2592,7 +2422,7 @@ version = "0.29.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "71e2746dc3a24dd78b3cfcb7be93368c6de9963d30f43a6a73998a9cf4b17b46"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "cfg-if",
  "cfg_aliases",
  "libc",
@@ -2605,7 +2435,7 @@ version = "0.30.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "74523f3a35e05aba87a1d978330aef40f67b0304ac79c1c00b294c9830543db6"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "cfg-if",
  "cfg_aliases",
  "libc",
@@ -2691,7 +2521,7 @@ version = "0.1.45"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1429034a0490724d0075ebb2bc9e875d6503c3cf69e235a8941aa757d83ef5bf"
 dependencies = [
- "autocfg 1.5.0",
+ "autocfg",
  "num-integer",
  "num-traits",
 ]
@@ -2702,7 +2532,7 @@ version = "0.2.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
 dependencies = [
- "autocfg 1.5.0",
+ "autocfg",
  "libm",
 ]
 
@@ -2721,7 +2551,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "73ad74d880bb43877038da939b7427bba67e9dd42004a18b809ba7d87cee241c"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "objc2",
  "objc2-foundation",
 ]
@@ -2742,7 +2572,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2a180dd8642fa45cdb7dd721cd4c11b1cadd4929ce112ebd8b9f5803cc79d536"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "dispatch2",
  "objc2",
 ]
@@ -2753,7 +2583,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e022c9d066895efa1345f8e33e584b9f958da2fd4cd116792e15e07e4720a807"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "dispatch2",
  "objc2",
  "objc2-core-foundation",
@@ -2786,7 +2616,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0cde0dfb48d25d2b4862161a4d5fcc0e3c24367869ad306b0c9ec0073bfed92d"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "objc2",
  "objc2-core-foundation",
  "objc2-core-graphics",
@@ -2804,7 +2634,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e3e0adef53c21f888deb4fa59fc59f7eb17404926ee8a6f59f5df0fd7f9f3272"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "block2",
  "libc",
  "objc2",
@@ -2817,7 +2647,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "180788110936d59bab6bd83b6060ffdfffb3b922ba1396b312ae795e1de9d81d"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "objc2",
  "objc2-core-foundation",
 ]
@@ -2828,7 +2658,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "96c1358452b371bf9f104e21ec536d37a650eb10f7ee379fff67d2e08d537f1f"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "objc2",
  "objc2-core-foundation",
  "objc2-foundation",
@@ -2840,7 +2670,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d87d638e33c06f577498cbcc50491496a3ed4246998a7fbba7ccb98b1e7eab22"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "block2",
  "objc2",
  "objc2-cloud-kit",
@@ -2892,7 +2722,7 @@ version = "0.10.79"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bf0b434746ee2832f4f0baf10137e1cabb18cbe6912c69e2e33263c45250f542"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "cfg-if",
  "foreign-types",
  "libc",
@@ -3280,7 +3110,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "syn 2.0.117",
- "version_check 0.9.5",
+ "version_check",
  "yansi",
 ]
 
@@ -3337,38 +3167,6 @@ version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dc33ff2d4973d518d823d61aa239014831e521c75da58e3df4840d3f47749d09"
 
-[[package]]
-name = "rand"
-version = "0.4.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "552840b97013b1a26992c11eac34bdd778e464601a4c2054b5f0bff7c6761293"
-dependencies = [
- "fuchsia-cprng",
- "libc",
- "rand_core 0.3.1",
- "rdrand",
- "winapi",
-]
-
-[[package]]
-name = "rand"
-version = "0.6.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6d71dacdc3c88c1fde3885a3be3fbab9f35724e6ce99467f7d9c5026132184ca"
-dependencies = [
- "autocfg 0.1.8",
- "libc",
- "rand_chacha 0.1.1",
- "rand_core 0.4.2",
- "rand_hc",
- "rand_isaac",
- "rand_jitter",
- "rand_os",
- "rand_pcg",
- "rand_xorshift",
- "winapi",
-]
-
 [[package]]
 name = "rand"
 version = "0.8.6"
@@ -3401,16 +3199,6 @@ dependencies = [
  "rand_core 0.10.1",
 ]
 
-[[package]]
-name = "rand_chacha"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "556d3a1ca6600bfcbab7c7c91ccb085ac7fbbcd70e008a98742e7847f4f7bcef"
-dependencies = [
- "autocfg 0.1.8",
- "rand_core 0.3.1",
-]
-
 [[package]]
 name = "rand_chacha"
 version = "0.3.1"
@@ -3431,21 +3219,6 @@ dependencies = [
  "rand_core 0.9.5",
 ]
 
-[[package]]
-name = "rand_core"
-version = "0.3.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7a6fdeb83b075e8266dcc8762c22776f6877a63111121f5f8c7411e5be7eed4b"
-dependencies = [
- "rand_core 0.4.2",
-]
-
-[[package]]
-name = "rand_core"
-version = "0.4.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9c33a3c44ca05fa6f1807d8e6743f3824e8509beca625669633be0acbdf509dc"
-
 [[package]]
 name = "rand_core"
 version = "0.6.4"
@@ -3470,77 +3243,6 @@ version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "63b8176103e19a2643978565ca18b50549f6101881c443590420e4dc998a3c69"
 
-[[package]]
-name = "rand_hc"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7b40677c7be09ae76218dc623efbf7b18e34bced3f38883af07bb75630a21bc4"
-dependencies = [
- "rand_core 0.3.1",
-]
-
-[[package]]
-name = "rand_isaac"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ded997c9d5f13925be2a6fd7e66bf1872597f759fd9dd93513dd7e92e5a5ee08"
-dependencies = [
- "rand_core 0.3.1",
-]
-
-[[package]]
-name = "rand_jitter"
-version = "0.1.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1166d5c91dc97b88d1decc3285bb0a99ed84b05cfd0bc2341bdf2d43fc41e39b"
-dependencies = [
- "libc",
- "rand_core 0.4.2",
- "winapi",
-]
-
-[[package]]
-name = "rand_os"
-version = "0.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7b75f676a1e053fc562eafbb47838d67c84801e38fc1ba459e8f180deabd5071"
-dependencies = [
- "cloudabi",
- "fuchsia-cprng",
- "libc",
- "rand_core 0.4.2",
- "rdrand",
- "winapi",
-]
-
-[[package]]
-name = "rand_pcg"
-version = "0.1.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "abf9b09b01790cfe0364f52bf32995ea3c39f4d2dd011eac241d2914146d0b44"
-dependencies = [
- "autocfg 0.1.8",
- "rand_core 0.4.2",
-]
-
-[[package]]
-name = "rand_xorshift"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cbf7e9e623549b0e21f6e97cf8ecf247c1a8fd2e8a992ae265314300b2455d5c"
-dependencies = [
- "rand_core 0.3.1",
-]
-
-[[package]]
-name = "rdrand"
-version = "0.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "678054eb77286b51581ba43620cc911abf02758c91f93f479767aed0f90458b2"
-dependencies = [
- "rand_core 0.3.1",
-]
-
 [[package]]
 name = "redis"
 version = "1.2.1"
@@ -3587,7 +3289,7 @@ version = "0.5.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ed2bf2547551a7053d6fdfafda3f938979645c44812fbfcda098faae3f1a362d"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
 ]
 
 [[package]]
@@ -3596,7 +3298,7 @@ version = "0.7.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4666a1a60d8412eab19d94f6d13dcc9cea0a5ef4fdf6a5db306537413c661b1b"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
 ]
 
 [[package]]
@@ -3649,7 +3351,7 @@ version = "0.13.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "62e0021ea2c22aed41653bc7e1419abb2c97e038ff2c33d0e1309e49a97deec0"
 dependencies = [
- "base64 0.22.1",
+ "base64",
  "bytes",
  "futures-channel",
  "futures-core",
@@ -3711,7 +3413,7 @@ dependencies = [
  "rkyv_derive",
  "seahash",
  "tinyvec",
- "uuid 1.23.1",
+ "uuid",
 ]
 
 [[package]]
@@ -3731,7 +3433,7 @@ version = "0.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4147b952f3f819eca0e99527022f7d6a8d05f111aeb0a62960c74eb283bec8fc"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "once_cell",
  "serde",
  "serde_derive",
@@ -3807,7 +3509,7 @@ version = "1.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b6fe4565b9518b83ef4f91bb47ce29620ca828bd32cb7e408f0062e9930ba190"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "errno",
  "libc",
  "linux-raw-sys",
@@ -3861,12 +3563,6 @@ version = "1.0.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9774ba4a74de5f7b1c1451ed6cd5285a32eddb5cccb8cc655a4e50009e06477f"
 
-[[package]]
-name = "safemem"
-version = "0.3.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ef703b7cb59335eae2eb93ceb664c0eb7ea6bf567079d843e09420219668e072"
-
 [[package]]
 name = "schannel"
 version = "0.1.29"
@@ -3924,10 +3620,10 @@ dependencies = [
  "sqlx",
  "strum",
  "thiserror 2.0.18",
- "time 0.3.47",
+ "time",
  "tracing",
  "url",
- "uuid 1.23.1",
+ "uuid",
 ]
 
 [[package]]
@@ -3969,8 +3665,8 @@ dependencies = [
  "rust_decimal",
  "sea-query-derive",
  "serde_json",
- "time 0.3.47",
- "uuid 1.23.1",
+ "time",
+ "uuid",
 ]
 
 [[package]]
@@ -4034,7 +3730,7 @@ version = "3.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b7f4bc775c73d9a02cde8bf7b2ec4c9d12743edf609006c7facc23998404cd1d"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "core-foundation",
  "core-foundation-sys",
  "libc",
@@ -4171,7 +3867,7 @@ version = "0.48.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c51ec9620a4d398dcdf7ee90effbf8d8691cfa24e91978bfa8565cac039d4980"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "sentry-backtrace",
  "sentry-core",
  "tracing-core",
@@ -4190,9 +3886,9 @@ dependencies = [
  "serde",
  "serde_json",
  "thiserror 2.0.18",
- "time 0.3.47",
+ "time",
  "url",
- "uuid 1.23.1",
+ "uuid",
 ]
 
 [[package]]
@@ -4435,7 +4131,7 @@ version = "0.8.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ee6798b1838b6a0f69c007c133b8df5866302197e404e8b6ee8ed3e3a5e68dc6"
 dependencies = [
- "base64 0.22.1",
+ "base64",
  "bytes",
  "chrono",
  "crc",
@@ -4460,12 +4156,12 @@ dependencies = [
  "sha2 0.10.9",
  "smallvec",
  "thiserror 2.0.18",
- "time 0.3.47",
+ "time",
  "tokio",
  "tokio-stream",
  "tracing",
  "url",
- "uuid 1.23.1",
+ "uuid",
  "webpki-roots 0.26.11",
 ]
 
@@ -4514,8 +4210,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "aa003f0038df784eb8fecbbac13affe3da23b45194bd57dba231c8f48199c526"
 dependencies = [
  "atoi",
- "base64 0.22.1",
- "bitflags 2.11.1",
+ "base64",
+ "bitflags",
  "byteorder",
  "bytes",
  "chrono",
@@ -4547,9 +4243,9 @@ dependencies = [
  "sqlx-core",
  "stringprep",
  "thiserror 2.0.18",
- "time 0.3.47",
+ "time",
  "tracing",
- "uuid 1.23.1",
+ "uuid",
  "whoami",
 ]
 
@@ -4560,8 +4256,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "db58fcd5a53cf07c184b154801ff91347e4c30d17a3562a635ff028ad5deda46"
 dependencies = [
  "atoi",
- "base64 0.22.1",
- "bitflags 2.11.1",
+ "base64",
+ "bitflags",
  "byteorder",
  "chrono",
  "crc",
@@ -4588,9 +4284,9 @@ dependencies = [
  "sqlx-core",
  "stringprep",
  "thiserror 2.0.18",
- "time 0.3.47",
+ "time",
  "tracing",
- "uuid 1.23.1",
+ "uuid",
  "whoami",
 ]
 
@@ -4615,10 +4311,10 @@ dependencies = [
  "serde_urlencoded",
  "sqlx-core",
  "thiserror 2.0.18",
- "time 0.3.47",
+ "time",
  "tracing",
  "url",
- "uuid 1.23.1",
+ "uuid",
 ]
 
 [[package]]
@@ -4787,17 +4483,6 @@ dependencies = [
  "cfg-if",
 ]
 
-[[package]]
-name = "time"
-version = "0.1.45"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1b797afad3f312d1c66a56d11d0316f916356d11bd158fbc6ca6389ff6bf805a"
-dependencies = [
- "libc",
- "wasi 0.10.0+wasi-snapshot-preview1",
- "winapi",
-]
-
 [[package]]
 name = "time"
 version = "0.3.47"
@@ -5000,7 +4685,7 @@ version = "0.6.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "68d6fdd9f81c2819c9a8b0e0cd91660e7746a8e6ea2ba7c6b2b057985f6bcb51"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "bytes",
  "futures-util",
  "http 1.4.0",
@@ -5180,7 +4865,7 @@ version = "3.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dea7109cdcd5864d4eeb1b58a1648dc9bf520360d7af16ec26d0a9354bafcfc0"
 dependencies = [
- "base64 0.22.1",
+ "base64",
  "der 0.8.0",
  "log",
  "native-tls",
@@ -5197,7 +4882,7 @@ version = "0.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e994ba84b0bd1b1b0cf92878b7ef898a5c1760108fe7b6010327e274917a808c"
 dependencies = [
- "base64 0.22.1",
+ "base64",
  "http 1.4.0",
  "httparse",
  "log",
@@ -5262,7 +4947,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "syn 2.0.117",
- "uuid 1.23.1",
+ "uuid",
 ]
 
 [[package]]
@@ -5277,15 +4962,6 @@ dependencies = [
  "utoipa",
 ]
 
-[[package]]
-name = "uuid"
-version = "0.7.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "90dbc611eb48397705a6b0f6e917da23ae517e4d127123d2cf7674206627d32a"
-dependencies = [
- "rand 0.6.5",
-]
-
 [[package]]
 name = "uuid"
 version = "1.23.1"
@@ -5340,12 +5016,6 @@ version = "0.2.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "accd4ea62f7bb7a82fe23066fb0957d48ef677f6eeb8215f372f52e48bb32426"
 
-[[package]]
-name = "version_check"
-version = "0.1.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "914b1a6776c4c929a602fafd8bc742e06365d4bcbe48c30f9cca5824f70dc9dd"
-
 [[package]]
 name = "version_check"
 version = "0.9.5"
@@ -5361,12 +5031,6 @@ dependencies = [
  "try-lock",
 ]
 
-[[package]]
-name = "wasi"
-version = "0.10.0+wasi-snapshot-preview1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1a143597ca7c7793eff794def352d41792a93c481eb1042423ff7ff72ba2c31f"
-
 [[package]]
 name = "wasi"
 version = "0.11.1+wasi-snapshot-preview1"
@@ -5481,7 +5145,7 @@ version = "0.244.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "47b807c72e1bac69382b3a6fb3dbe8ea4c0ed87ff5629b8685ae6b9a611028fe"
 dependencies = [
- "bitflags 2.11.1",
+ "bitflags",
  "hashbrown 0.15.5",
  "indexmap",
  "semver",
@@ -5836,7 +5500,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9d66ea20e9553b30172b5e831994e35fbde2d165325bec84fc43dbf6f4eb9cb2"
 dependencies = [
  "anyhow",
- "bitflags 2.11.1",
+ "bitflags",
  "indexmap",
  "log",
  "serde",
diff --git a/apps/backend/Cargo.toml b/apps/backend/Cargo.toml
index daa38f2..5da8cf6 100644
--- a/apps/backend/Cargo.toml
+++ b/apps/backend/Cargo.toml
@@ -45,4 +45,3 @@ subtle = "2.4"
 strum = { version = "0.28.0", features = ["derive"] }
 strum_macros = "0.28"
 lettre = { version = "0.11", default-features = false, features = ["builder", "hostname", "smtp-transport","tokio1", "tokio1-rustls-tls"] }
-lettre_email = "0.9"
\ No newline at end of file
diff --git a/apps/backend/src/lib.rs b/apps/backend/src/lib.rs
index 52ae936..9daecef 100644
--- a/apps/backend/src/lib.rs
+++ b/apps/backend/src/lib.rs
@@ -1,4 +1,7 @@
-use crate::{settings::Settings, utils::{redis::RedisConnection, smtp::SmtpClient}};
+use crate::{
+    settings::Settings,
+    utils::{redis::RedisConnection, smtp::SmtpClient},
+};
 use sea_orm::DatabaseConnection;
 
 pub mod dto;
@@ -17,5 +20,5 @@ pub struct AppState {
     pub settings: Settings,
     pub db: DatabaseConnection,
     pub redis_client: RedisConnection,
-    pub smtp_client: SmtpClient
+    pub smtp_client: SmtpClient,
 }
diff --git a/apps/backend/src/main.rs b/apps/backend/src/main.rs
index a77663a..b763c21 100644
--- a/apps/backend/src/main.rs
+++ b/apps/backend/src/main.rs
@@ -24,7 +24,12 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         settings.smtp_port,
         &settings.smtp_username,
         &settings.smtp_password,
-    )?;
+         )
+     .map_err(|err| {
+         std::io::Error::other(format!(
+             "SMTP client initialization failed. If email is required in this environment, check smtp_host/smtp_port/smtp_username/smtp_password. Underlying error: {err}"
+         ))
+     })?;
     let redis_client = backend::utils::redis::RedisConnection::new(&settings.redis_url);
     redis_client.ping().await?;
     let state = AppState {
diff --git a/apps/backend/src/utils/auth.rs b/apps/backend/src/utils/auth.rs
index f628caa..78fe0d1 100644
--- a/apps/backend/src/utils/auth.rs
+++ b/apps/backend/src/utils/auth.rs
@@ -1,6 +1,9 @@
 use argon2::{
     Argon2,
-    password_hash::{PasswordHash, PasswordHasher, PasswordVerifier, SaltString, rand_core::{OsRng, RngCore}},
+    password_hash::{
+        PasswordHash, PasswordHasher, PasswordVerifier, SaltString,
+        rand_core::{OsRng, RngCore},
+    },
 };
 
 use axum::{
diff --git a/apps/backend/src/utils/smtp.rs b/apps/backend/src/utils/smtp.rs
index 5f9154d..d2ea4b8 100644
--- a/apps/backend/src/utils/smtp.rs
+++ b/apps/backend/src/utils/smtp.rs
@@ -1,14 +1,16 @@
-use std::time::Duration;
-
-/// SMTPクライアントを提供するモジュール
+//! SMTPクライアントを提供するモジュール
 
+use lettre::Tokio1Executor;
 use lettre::message::{Mailbox, Message, MultiPart, SinglePart};
 use lettre::{AsyncSmtpTransport, AsyncTransport, transport::smtp::authentication::Credentials};
-use lettre::Tokio1Executor;
+use std::time::Duration;
 use tokio::time::timeout;
 
+/// SMTP送信タイムアウト（秒）
+const SMTP_SEND_TIMEOUT_SECS: u64 = 30;
+
 /// SMTPクライアントの構造体
-#[derive(Clone, Debug)]
+#[derive(Clone)]
 pub struct SmtpClient {
     mailer: AsyncSmtpTransport<Tokio1Executor>,
 }
@@ -16,47 +18,47 @@ pub struct SmtpClient {
 /// SmtpClientの実装
 impl SmtpClient {
     /// 新しいSMTPクライアントを作成する関数
-    /// 
+    ///
     /// # Arguments
     /// * `smtp_server` - SMTPサーバーのアドレス
     /// * `smtp_port` - SMTPサーバーのポート番号
     /// * `username` - SMTPサーバーの認証に使用するユーザー名
     /// * `password` - SMTPサーバーの認証に使用するパスワード
-    /// 
+    ///
     ///  # Examples
-    /// 
+    ///
     ///  ```no_run
     /// use backend::utils::smtp::SmtpClient;
     ///
     /// let smtp_client = SmtpClient::new("smtp.example.com", 587, "user", "pass").unwrap();
     /// ```
     pub fn new(
-        smtp_server: &str, 
-        smtp_port: u16, 
-        username: &str, 
-        password: &str
+        smtp_server: &str,
+        smtp_port: u16,
+        username: &str,
+        password: &str,
     ) -> Result<Self, lettre::transport::smtp::Error> {
         let creds = Credentials::new(username.to_string(), password.to_string());
-        
+
         let mailer = AsyncSmtpTransport::<Tokio1Executor>::starttls_relay(smtp_server)?
             .port(smtp_port)
             .credentials(creds)
             .build();
-            
+
         Ok(SmtpClient { mailer })
     }
 
     /// メールを送信する関数
-    /// 
+    ///
     /// # Arguments
     /// * `from` - 送信元のメールアドレス
     /// * `to` - 送信先のメールアドレス
     /// * `subject` - メールの件名
     /// * `body_text` - メールのテキスト形式の本文
     /// * `body_html` - メールのHTML形式の本文（オプション）
-    /// 
+    ///
     /// # Examples
-    /// 
+    ///
     /// ```no_run
     /// use backend::utils::smtp::SmtpClient;
     ///
@@ -81,7 +83,6 @@ impl SmtpClient {
         body_text: &str,
         body_html: Option<&str>,
     ) -> Result<(), Box<dyn std::error::Error>> {
-        
         let builder = Message::builder()
             .from(from.parse::<Mailbox>()?)
             .to(to.parse::<Mailbox>()?)
@@ -97,10 +98,13 @@ impl SmtpClient {
         };
 
         // 送信処理にタイムアウトを30秒に設定
-        let _ = timeout(Duration::from_secs(30), self.mailer.send(email))
-            .await
-            .map_err(|_| "SMTP send timeout")?;
-        
+        timeout(
+            Duration::from_secs(SMTP_SEND_TIMEOUT_SECS),
+            self.mailer.send(email),
+        )
+        .await
+        .map_err(|_| "SMTP send timeout")??;
+
         Ok(())
     }
-}
\ No newline at end of file
+}

From 833e21fdb3a3896278614855c4bfe55fc63e6e61 Mon Sep 17 00:00:00 2001
From: yupix <yupi0982@outlook.jp>
Date: Mon, 18 May 2026 08:24:02 +0000
Subject: [PATCH 9/9] refactor(backend): Remove Debug derive from Settings
 struct for cleaner code

---
 apps/backend/src/settings.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/apps/backend/src/settings.rs b/apps/backend/src/settings.rs
index 720d1dc..a1ec837 100644
--- a/apps/backend/src/settings.rs
+++ b/apps/backend/src/settings.rs
@@ -1,7 +1,7 @@
 use config::{Config, Environment};
 use serde::Deserialize;
 
-#[derive(Clone, Debug, Deserialize)]
+#[derive(Clone, Deserialize)]
 pub struct Settings {
     pub database_url: String,
     pub redis_url: String,