diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
new file mode 100644
index 00000000000..2f76be5dfa8
--- /dev/null
+++ b/.devcontainer/Dockerfile
@@ -0,0 +1,20 @@
+# Make sure RUBY_VERSION matches the Ruby version in .ruby-version
+ARG RUBY_VERSION=3.4.7
+FROM ghcr.io/rails/devcontainer/images/ruby:$RUBY_VERSION
+
+USER root
+ENV DEBIAN_FRONTEND=noninteractive
+
+# Required on Windows
+RUN mkdir -p /workspaces/openstreetmap-website \
+    && chown -R vscode:vscode /workspaces/openstreetmap-website
+
+# Install system packages then clean up to minimize image size
+RUN apt-get update \
+  && apt-get install --no-install-recommends -y \
+    file \
+    libarchive-dev \
+    libgd-dev \
+    osmosis \
+  && apt-get clean \
+  && apt-get distclean
diff --git a/.devcontainer/compose.yaml b/.devcontainer/compose.yaml
new file mode 100644
index 00000000000..7cb518323aa
--- /dev/null
+++ b/.devcontainer/compose.yaml
@@ -0,0 +1,53 @@
+name: "open_street_map"
+
+services:
+  rails-app:
+    build:
+      context: ..
+      dockerfile: .devcontainer/Dockerfile
+
+    volumes:
+    - ../..:/workspaces:cached
+    - mise-cache:/home/vscode/.local/share/mise
+
+    # Overrides default command so things don't shut down after the process ends.
+    command: sleep infinity
+
+    # Uncomment the next line to use a non-root user for all processes.
+    # user: vscode
+
+    # Use "forwardPorts" in **devcontainer.json** to forward an app port locally.
+    # (Adding the "ports" property to this file will not forward from a Codespace.)
+    depends_on:
+    - selenium-default
+    - selenium-de
+    - selenium-nolang
+    - postgres
+
+  selenium-default:
+    image: selenium/standalone-firefox
+    restart: unless-stopped
+
+  selenium-de:
+    image: selenium/standalone-firefox
+    restart: unless-stopped
+
+  selenium-nolang:
+    image: selenium/standalone-firefox
+    restart: unless-stopped
+
+  postgres:
+    image: postgres:16.1
+    restart: unless-stopped
+    networks:
+    - default
+    volumes:
+    - postgres-data:/var/lib/postgresql/data
+    environment:
+      POSTGRES_DB: openstreetmap
+      POSTGRES_USER: openstreetmap
+      POSTGRES_PASSWORD: openstreetmap
+
+volumes:
+  postgres-data:
+  mise-cache:
diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
new file mode 100644
index 00000000000..88a00f971e6
--- /dev/null
+++ b/.devcontainer/devcontainer.json
@@ -0,0 +1,34 @@
+// For format details, see https://containers.dev/implementors/json_reference/.
+// For config options, see the README at: https://github.com/devcontainers/templates/tree/main/src/ruby
+{
+  "name": "open_street_map",
+  "dockerComposeFile": "compose.yaml",
+  "service": "rails-app",
+  "workspaceFolder": "/workspaces/${localWorkspaceFolderBasename}",
+
+  // Features to add to the dev container. More info: https://containers.dev/features.
+  "features": {
+    "ghcr.io/devcontainers/features/github-cli:1": {},
+    "ghcr.io/devcontainers/features/node:1": {},
+    "ghcr.io/rails/devcontainer/features/activestorage": {},
+    "ghcr.io/rails/devcontainer/features/postgres-client": {}
+  },
+
+  "containerEnv": {
+    "CAPYBARA_SERVER_PORT": "45678",
+    "DB_HOST": "postgres"
+  },
+
+  // Use 'forwardPorts' to make a list of ports inside the container available locally.
+  "forwardPorts": [3000, 5432],
+
+  // Configure tool-specific properties.
+  // "customizations": {},
+
+  // Uncomment to connect as root instead. More info: https://containers.dev/implementors/json_reference/#remoteUser.
+  // "remoteUser": "root",
+
+
+  // Use 'postCreateCommand' to run commands after the container is created.
+  "postCreateCommand": ".devcontainer/start"
+}
diff --git a/.devcontainer/start b/.devcontainer/start
new file mode 100755
index 00000000000..9b4d529c7d4
--- /dev/null
+++ b/.devcontainer/start
@@ -0,0 +1,11 @@
+#!/usr/bin/env sh
+
+# This setup uses https://mise.jdx.dev to manage language versions.
+# Mark the config file as trusted to avoid an interactive prompt.
+mise trust /workspaces/mise.local.toml
+
+cp config/devcontainer.database.yml config/database.yml
+cp config/example.storage.yml config/storage.yml
+touch config/settings.local.yml
+
+bin/setup --skip-server
diff --git a/.github/workflows/devcontainer.yml b/.github/workflows/devcontainer.yml
new file mode 100644
index 00000000000..de0d1f6e689
--- /dev/null
+++ b/.github/workflows/devcontainer.yml
@@ -0,0 +1,21 @@
+name: devcontainer
+
+on:
+  - push
+  - pull_request
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout (GitHub)
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+
+      - name: Build and run dev container task
+        uses: devcontainers/ci@8bf61b26e9c3a98f69cb6ce2f88d24ff59b785c6 # v0.3.1900000417
+        with:
+          runCmd: bin/rails test:all
diff --git a/DEVCONTAINER.md b/DEVCONTAINER.md
new file mode 100644
index 00000000000..10b02513342
--- /dev/null
+++ b/DEVCONTAINER.md
@@ -0,0 +1,141 @@
+# Using Development Containers for development and testing
+
+You can set up a development environment for this project using [Development Containers](https://containers.dev/), aka devcontainers.
+
+There are different ways of working with devcontainers. Some are automated and integrated in IDE applications, while others are more manual and require CLI tools. This guide will use [Visual Studio Code](https://code.visualstudio.com) and assumes that it's installed already.
+
+Be aware that the containers will take significant space in your hard drive, in the region of 6GB.
+
+## Install Git
+
+You will need Git to clone (download) the code repository and push changes. How to install Git will depend on your operating system.
+
+### Ubuntu 24.04 LTS, Debian 13 (Trixie)
+
+```bash
+sudo apt-get update
+sudo apt-get install git-core
+```
+
+### Fedora
+
+```bash
+sudo dnf install git
+```
+
+### macOS
+
+For macOS, you will need [Xcode Command Line Tools](https://mac.install.guide/commandlinetools/); macOS 14 (Sonoma) or later; and some familiarity with Unix development via the Terminal.
+
+### Windows
+
+You can install Git using [WinGet](https://learn.microsoft.com/en-gb/windows/package-manager/winget/):
+
+```bash
+winget install --id Git.Git -e --source winget
+```
+
+Alternatively, see [other install options](https://git-scm.com/install/windows).
+
+## Install Docker
+
+You will need to install Docker in order to run devcontainers. Again, the methods will depend on your operating system.
+
+In general: if you get an error about not having permission to use Docker, you may need to add your user to the `docker` group. The details vary, but often this is a case of running the following command:
+
+```bash
+sudo usermod --append --group docker $USERNAME
+```
+
+Substitute `$USERNAME` with your actual username in the command above. After that, reboot your computer to ensure that this change takes effect.
+
+### Windows
+
+1. Use Docker Desktop via [docker.com Download](https://www.docker.com/products/docker-desktop/).
+
+2. You have to enable git symlinks before cloning the repository.
+   This repository uses symbolic links that are not enabled by default on Windows git. To enable them, [turn on Developer Mode](https://windowsreport.com/windows-11-developer-mode/) on Windows and run `git config --global core.symlinks true` to enable symlinks in Git. See [this StackOverflow question](https://stackoverflow.com/questions/5917249/git-symbolic-links-in-windows) for more information.
+
+### Mac
+
+- Use Docker Desktop via [docker.com Download](https://www.docker.com/products/docker-desktop/).
+- Or [Homebrew](https://formulae.brew.sh/cask/docker).
+
+### Linux
+
+Use [Docker Engine](https://docs.docker.com/engine/install/ubuntu/) with the [docker-compose-plugin](https://docs.docker.com/compose/install/linux/)
+
+## Clone the repository
+
+The repository is reasonably large (~560MB) and it's unlikely that you'll need the full history. Therefore you can probably do with a shallow clone (~100MB):
+```bash
+git clone --depth=1 https://github.com/openstreetmap/openstreetmap-website.git
+```
+
+If you want to add in the full history later on, perhaps to run `git blame` or `git log`, run `git fetch --unshallow`.
+
+> [!TIP]
+> To download the full history from the start, run:
+> ```bash
+> git clone https://github.com/openstreetmap/openstreetmap-website.git
+> ```
+
+## Install Dev Containers extension
+
+Start by opening the project with VS Code. Within it, you will need to install the extension _Dev Containers_, which can be done from the _Extensions_ section, reachable via the sidebar icons. Or VS Code may show a popup recommending this extension, with a button to install it directly.
+
+![VS Code: panel to install extensions](./docs/assets/vscode-devcontainers-extension.png)
+
+## Open the project in a container
+
+If everything is correct, this should make a few new commands available to you within VS Code. Find and run the command "Dev Containers: Reopen in Container".
+
+![VS Code: command to open in a devcontainer](./docs/assets/vscode-dev-reopen.png)
+
+The first time you do this, it will go into a bit of a process. It will create the devcontainer, pull the Docker images, install the dependencies, etc. Go drink some water while this runs.
+
+![VS Code: notification that VS Code is connecting to the Dev Container](./docs/assets/vscode-connecting-to-devcontainer.png)
+
+Eventually this will present you with a development environment ready to go. In subsequent occasions this should be much faster.
+
+## Done!
+
+If everything went well, you are done! For example, now you can open a shell in this environment using the VS Studio command "Create New Terminal (With Profile)":
+
+![VS Code: command to open a terminal](./docs/assets/vscode-create-terminal.png)
+
+From this terminal, you can run the test suite with `bundle exec rails test:all`:
+
+![Running the test suite in the terminal](./docs/assets/vscode-rails-test-all.png)
+
+Hopefully it should be all green? 🤞 You can also start a development server with `bundle exec rails s`:
+
+![Running the dev server in the terminal](./docs/assets/vscode-rails-server.png)
+
+It will take a moment to start, after which you will be able to take a browser to http://localhost:3000 and visit your own local version of the site.
+
+## Other useful configuration
+
+See [`CONFIGURE.md`](CONFIGURE.md) for information on how to manage users and enable OAuth for iD, JOSM etc.
+
+## Other tools
+
+VS Code is not the only way to work with devcontainers. Other options include:
+
+- [RubyMine](https://www.jetbrains.com/help/ruby/start-dev-container-inside-ide.html): another popular environment to work with Ruby.
+- [DevPod](https://devpod.sh): a CLI tool to work with devcontainers.
+- [VSCodium](https://vscodium.com): a Free/Libre alternative to VS Code.
+- [GitHub Codespaces](https://github.com/codespaces): GitHub's hosted IDE.
+
+## Troubleshooting
+
+### `‘ruby’: No such file or directory`
+
+In some cases Ruby may not install correctly. If you see this message, run these two commands:
+
+```
+mise install
+bundle install
+```
+
+This has been observed particularly when using RubyMine.
diff --git a/INSTALL.md b/INSTALL.md
index 7bf580b1ed0..1c4abf9182a 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -8,14 +8,17 @@ There is more than one way to set up a development environment.
 
 ### Containerized Installation
 
-We offer a containerized environment with Docker which may avoid installation difficulties. See [DOCKER.md](DOCKER.md) for complete instructions.
+We offer containerized environments with Docker which may avoid installation difficulties:
+
+- To use Docker manually, see [DOCKER](DOCKER.md).
+- To use Docker via [Development Containers](https://containers.dev) (devcontainers), see [DEVCONTAINER.md](DEVCONTAINER.md).
 
 ### Manual Installation
 
 Install dependencies directly on your machine (traditional approach, covered in this guide). This gives you the most control and is often preferred by experienced developers on Linux systems.
 
 > [!WARNING]
-> **Windows Note:** We don't recommend using this approach on Windows, as some Ruby gems may not be supported. If you are using Windows, we recommend containerized setup using [Docker](DOCKER.md).
+> **Windows Note:** We don't recommend using this approach on Windows, as some Ruby gems may not be supported. If you are using Windows, we recommend a containerized setup as mentioned above.
 
 ## Manual Installation Guide
 
diff --git a/bin/setup b/bin/setup
index f882c0024ed..ccac37778a5 100755
--- a/bin/setup
+++ b/bin/setup
@@ -16,6 +16,7 @@ FileUtils.chdir APP_ROOT do
 
   puts "== Installing dependencies =="
   system("bundle check") || system!("bundle install")
+  system("yarn install --check-dependencies")
 
   # puts "\n== Copying sample files =="
   # unless File.exist?("config/database.yml")
diff --git a/config/devcontainer.database.yml b/config/devcontainer.database.yml
new file mode 100644
index 00000000000..f65469580c1
--- /dev/null
+++ b/config/devcontainer.database.yml
@@ -0,0 +1,20 @@
+# This configuration is tailored for use with devcontainers. See DEVCONTAINER.md for more information.
+
+development:
+  adapter: postgresql
+  database: openstreetmap
+  username: openstreetmap
+  password: openstreetmap
+  host: <%= ENV["DB_HOST"] %>
+  encoding: utf8
+  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+
+test:
+  adapter: postgresql
+  database: osm_test
+  username: openstreetmap
+  password: openstreetmap
+  host: <%= ENV["DB_HOST"] %>
+  encoding: utf8
+  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+
diff --git a/docs/assets/vscode-connecting-to-devcontainer.png b/docs/assets/vscode-connecting-to-devcontainer.png
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index 00000000000..10666d7f99c
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diff --git a/docs/assets/vscode-create-terminal.png b/docs/assets/vscode-create-terminal.png
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index 00000000000..07d1ad61eaf
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diff --git a/docs/assets/vscode-dev-reopen.png b/docs/assets/vscode-dev-reopen.png
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new file mode 100644
index 00000000000..976b5cf05f9
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diff --git a/docs/assets/vscode-rails-server.png b/docs/assets/vscode-rails-server.png
new file mode 100644
index 00000000000..9b82ba7c95e
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diff --git a/docs/assets/vscode-rails-test-all.png b/docs/assets/vscode-rails-test-all.png
new file mode 100644
index 00000000000..24b1028db98
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diff --git a/docs/assets/vscode-reopen-devcontainer.png b/docs/assets/vscode-reopen-devcontainer.png
new file mode 100644
index 00000000000..329cc5be457
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diff --git a/docs/assets/vscode-terminal-ready.png b/docs/assets/vscode-terminal-ready.png
new file mode 100644
index 00000000000..fb1a8be10e9
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diff --git a/test/application_system_test_case.rb b/test/application_system_test_case.rb
index e10501f2b71..be7b35f0cac 100644
--- a/test/application_system_test_case.rb
+++ b/test/application_system_test_case.rb
@@ -15,11 +15,41 @@ class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
     config.enable_aria_label = true
   end
 
-  driven_by :selenium, :using => Settings.system_test_headless ? :headless_firefox : :firefox do |options|
-    options.add_preference("intl.accept_languages", "en")
-    options.binary = Settings.system_test_firefox_binary if Settings.system_test_firefox_binary
+  cattr_accessor(:capybara_server_port) { ENV.fetch("CAPYBARA_SERVER_PORT", nil) }
+
+  served_by :host => "rails-app", :port => capybara_server_port if capybara_server_port
+
+  def self.driven_by_selenium(config_name = "default", opts = {})
+    preferences = opts.fetch(:preferences, {}).reverse_merge(
+      "intl.accept_languages" => "en"
+    )
+
+    options = {
+      :name => config_name
+    }
+
+    if capybara_server_port
+      selenium_host = "http://selenium-#{config_name}:4444"
+      options = options.merge(
+        :url => selenium_host,
+        :browser => :remote
+      )
+    end
+
+    driven_by(
+      :selenium,
+      :using => Settings.system_test_headless ? :headless_firefox : :firefox,
+      :options => options
+    ) do |options|
+      preferences.each do |name, value|
+        options.add_preference(name, value)
+      end
+      options.binary = Settings.system_test_firefox_binary if Settings.system_test_firefox_binary
+    end
   end
 
+  driven_by_selenium
+
   def before_setup
     super
     osm_website_app = create(:oauth_application, :name => "OpenStreetMap Web Site", :scopes => "write_api write_notes")
diff --git a/test/system/embed_test.rb b/test/system/embed_test.rb
index 2c798832be1..e906866ea35 100644
--- a/test/system/embed_test.rb
+++ b/test/system/embed_test.rb
@@ -10,9 +10,12 @@ class EmbedTest < ApplicationSystemTestCase
 end
 
 class GermanEmbedTest < ApplicationSystemTestCase
-  driven_by :selenium, :using => :headless_firefox, :options => { :name => :selenium_de } do |options|
-    options.add_preference("intl.accept_languages", "de")
-  end
+  driven_by_selenium(
+    "de",
+    :preferences => {
+      "intl.accept_languages" => "de"
+    }
+  )
 
   test "shows localized report link" do
     visit export_embed_path
@@ -21,9 +24,12 @@ class GermanEmbedTest < ApplicationSystemTestCase
 end
 
 class UnknownLanguageEmbedTest < ApplicationSystemTestCase
-  driven_by :selenium, :using => :headless_firefox, :options => { :name => :selenium_unknown_language } do |options|
-    options.add_preference("intl.accept_languages", "unknown-language")
-  end
+  driven_by_selenium(
+    "nolang",
+    :preferences => {
+      "intl.accept_languages" => "unknown-language"
+    }
+  )
 
   test "shows report link in fallback language" do
     visit export_embed_path
diff --git a/test/test_helper.rb b/test/test_helper.rb
index ef159b0d475..1dc91f16266 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -36,7 +36,7 @@ def self.branch_coverage?
 require "webmock/minitest"
 require "minitest/focus" unless ENV["CI"]
 
-WebMock.disable_net_connect!(:allow_localhost => true)
+WebMock.disable_net_connect!(:allow_localhost => true, :allow => %w[selenium-default selenium-de selenium-nolang rails-app])
 
 module ActiveSupport
   class TestCase
@@ -44,15 +44,21 @@ class TestCase
     include ActiveJob::TestHelper
     include LibXML
 
-    # Run tests in parallel with specified workers
-    parallelize(:workers => :number_of_processors)
+    if ENV.key?("CAPYBARA_SERVER_PORT")
+      # Running in the devcontainer. Can't figure out how
+      # to run things in parallel at the moment, so for now
+      # we are not doing it.
+    else
+      # Run tests in parallel with specified workers
+      parallelize(:workers => :number_of_processors)
 
-    parallelize_setup do |worker|
-      SimpleCov.command_name "#{SimpleCov.command_name}-#{worker}"
-    end
+      parallelize_setup do |worker|
+        SimpleCov.command_name "#{SimpleCov.command_name}-#{worker}"
+      end
 
-    parallelize_teardown do
-      SimpleCov.result
+      parallelize_teardown do
+        SimpleCov.result
+      end
     end
 
     ##