diff --git a/.buildkite/cleanup-pr-build-branches.sh b/.buildkite/cleanup-pr-build-branches.sh
new file mode 100755
index 00000000..13db49b6
--- /dev/null
+++ b/.buildkite/cleanup-pr-build-branches.sh
@@ -0,0 +1,86 @@
+#!/bin/bash
+
+set -euo pipefail
+
+# Deletes `pr-build/<n>` branches whose PR is closed (merged or rejected).
+# Runs on trunk pushes so the just-merged PR's branch gets cleaned up
+# immediately, and any orphans accumulated from prior failures get swept too.
+
+if [[ "${BUILDKITE_BRANCH:-}" != "trunk" ]]; then
+    echo "Not a trunk build (branch=${BUILDKITE_BRANCH:-unset}), skipping"
+    exit 0
+fi
+
+if [[ -z "${GITHUB_TOKEN:-}" ]]; then
+    echo "GITHUB_TOKEN not set, cannot query PR state" >&2
+    exit 1
+fi
+
+GITHUB_REPO="wordpress-mobile/GutenbergKit"
+
+echo '--- :robot_face: Use bot for Git operations'
+source use-bot-for-git
+
+echo "--- :mag: Listing pr-build/* branches on origin"
+mapfile -t branches < <(
+    git ls-remote --heads origin 'refs/heads/pr-build/*' \
+        | awk '{print $2}' \
+        | sed 's|^refs/heads/||'
+)
+
+echo "Found ${#branches[@]} pr-build branches"
+
+if [[ ${#branches[@]} -eq 0 ]]; then
+    exit 0
+fi
+
+echo "--- :github: Checking PR state for each branch"
+to_delete=()
+for branch in "${branches[@]}"; do
+    pr_number="${branch#pr-build/}"
+    if ! [[ "$pr_number" =~ ^[0-9]+$ ]]; then
+        echo "Skipping $branch (unexpected suffix)"
+        continue
+    fi
+
+    response=$(
+        curl --silent --show-error \
+            --write-out $'\n%{http_code}' \
+            --header "Authorization: Bearer ${GITHUB_TOKEN}" \
+            --header "Accept: application/vnd.github+json" \
+            --header "X-GitHub-Api-Version: 2022-11-28" \
+            "https://api.github.com/repos/${GITHUB_REPO}/pulls/${pr_number}"
+    )
+    http_code=$(printf '%s' "$response" | tail -n1)
+    body=$(printf '%s' "$response" | sed '$d')
+
+    if [[ "$http_code" != "200" ]]; then
+        echo "Skipping $branch (HTTP $http_code from GitHub)"
+        continue
+    fi
+
+    state=$(printf '%s' "$body" | jq -r '.state')
+
+    if [[ "$state" == "closed" ]]; then
+        echo "Marking $branch for deletion (PR #$pr_number is closed)"
+        to_delete+=("$branch")
+    else
+        echo "Keeping $branch (PR #$pr_number is $state)"
+    fi
+done
+
+if [[ ${#to_delete[@]} -eq 0 ]]; then
+    echo "No closed PR branches to delete"
+    exit 0
+fi
+
+echo "--- :wastebasket: Deleting ${#to_delete[@]} stale branches"
+chunk_size=50
+for ((i=0; i<${#to_delete[@]}; i+=chunk_size)); do
+    chunk=("${to_delete[@]:i:chunk_size}")
+    refspecs=()
+    for branch in "${chunk[@]}"; do
+        refspecs+=(":refs/heads/${branch}")
+    done
+    git push origin "${refspecs[@]}"
+done
diff --git a/.buildkite/pipeline.yml b/.buildkite/pipeline.yml
index fac81e13..4ac39985 100644
--- a/.buildkite/pipeline.yml
+++ b/.buildkite/pipeline.yml
@@ -80,8 +80,8 @@ steps:
     - label: ':xcode: Build XCFramework'
       key: build-xcframework
       depends_on:
-        - build-react
-        - swift-test-library
+          - build-react
+          - swift-test-library
       command: |
           buildkite-agent artifact download dist.tar.gz .
           tar -xzf dist.tar.gz
@@ -97,6 +97,7 @@ steps:
 
     - label: ':s3: Publish XCFramework to S3'
       depends_on: build-xcframework
+      if: build.pull_request.id == null
       command: |
           buildkite-agent artifact download '*.xcframework.zip' .
           buildkite-agent artifact download '*.xcframework.zip.checksum.txt' .
@@ -107,6 +108,12 @@ steps:
           bundle exec fastlane publish_to_s3 version:${NEW_VERSION:-${BUILDKITE_TAG:-$BUILDKITE_COMMIT}}
       plugins: *plugins
 
+    - label: ':swift: :package: Publish PR XCFramework'
+      depends_on: build-xcframework
+      if: build.pull_request.id != null
+      command: .buildkite/publish-pr-xcframework.sh
+      plugins: *plugins
+
     - label: ':ios: Test iOS E2E'
       depends_on: build-react
       command: |
@@ -149,3 +156,8 @@ steps:
           - 'android/Gutenberg/build/outputs/androidTest-results/connected/**/*'
           - 'android/Gutenberg/build/outputs/buildkite-logs/**/*'
           - 'android/Gutenberg/build/outputs/connected_android_test_additional_output/**/*'
+
+    - label: ':wastebasket: Clean up `pr-build/*` branches for closed PRs'
+      if: build.branch == "trunk"
+      command: .buildkite/cleanup-pr-build-branches.sh
+      plugins: *plugins
diff --git a/.buildkite/publish-pr-xcframework.sh b/.buildkite/publish-pr-xcframework.sh
new file mode 100755
index 00000000..a25b0354
--- /dev/null
+++ b/.buildkite/publish-pr-xcframework.sh
@@ -0,0 +1,28 @@
+#!/bin/bash
+set -euo pipefail
+
+if [[ "${BUILDKITE_PULL_REQUEST:-false}" == "false" ]]; then
+    echo "Not a PR build, skipping PR XCFramework publish"
+    exit 0
+fi
+
+# Skip on fork PRs: bot credentials and S3 secrets aren't available, and we
+# couldn't push the snapshot branch back to the canonical repo anyway.
+if [[ -n "${BUILDKITE_PULL_REQUEST_REPO:-}" ]] \
+    && [[ "$BUILDKITE_PULL_REQUEST_REPO" != *"wordpress-mobile/GutenbergKit"* ]]; then
+    echo "PR is from a fork (${BUILDKITE_PULL_REQUEST_REPO}), skipping XCFramework publish"
+    exit 0
+fi
+
+echo '--- :robot_face: Use bot for Git operations'
+source use-bot-for-git
+
+echo '--- :arrow_down: Downloading XCFramework artifacts'
+buildkite-agent artifact download '*.xcframework.zip' . --step "build-xcframework"
+buildkite-agent artifact download '*.xcframework.zip.checksum.txt' . --step "build-xcframework"
+
+echo '--- :rubygems: Setting up Gems'
+install_gems
+
+echo "--- :rocket: Publishing PR build for PR #${BUILDKITE_PULL_REQUEST}"
+bundle exec fastlane publish_pr_xcframework
diff --git a/fastlane/Fastfile b/fastlane/Fastfile
index c4af8566..d5984c4e 100644
--- a/fastlane/Fastfile
+++ b/fastlane/Fastfile
@@ -1,9 +1,14 @@
 # frozen_string_literal: true
 
+require 'fastlane/plugin/wpmreleasetoolkit'
+
 PROJECT_ROOT = File.expand_path('..', __dir__)
 
 APPLE_TEAM_ID = 'PZYM8XX95Q'
 
+GITHUB_REPO = 'wordpress-mobile/GutenbergKit'
+XCFRAMEWORK_COMMENT_REUSE_ID = 'gutenbergkit-xcframework-build'
+
 ASC_API_KEY_ENV_VARS = %w[
   APP_STORE_CONNECT_API_KEY_KEY_ID
   APP_STORE_CONNECT_API_KEY_ISSUER_ID
@@ -15,6 +20,12 @@ CODE_SIGNING_STORAGE_ENV_VARS = %w[
   MATCH_S3_SECRET_ACCESS_KEY
 ].freeze
 
+# Set up the release-toolkit env manager so lanes can read CI metadata
+# (`pull_request_number`, `commit_hash`, etc.) via a single canonical helper.
+# We don't ship a `.env` file; on CI the values come straight from the process
+# environment, and off-CI the manager will warn (not fail) about the missing file.
+Fastlane::Wpmreleasetoolkit::EnvManager.set_up(env_file_name: 'gutenbergkit.env')
+
 before_all do
   setup_ci
 end
@@ -39,6 +50,27 @@ lane :publish_to_s3 do |options|
   )
 end
 
+lane :publish_pr_xcframework do
+  env = Fastlane::Wpmreleasetoolkit::EnvManager.default!
+  pr_number = env.pull_request_number
+  UI.user_error!('publish_pr_xcframework must run on a PR build (BUILDKITE_PULL_REQUEST is unset or "false")') if pr_number.nil?
+
+  branch_name = "pr-build/#{pr_number}"
+  version = "pr-builds/#{pr_number}"
+
+  publish_to_s3(version: version)
+  push_xcframework_snapshot_branch(branch_name: branch_name, version: version, checksum: xcframework_checksum)
+
+  body = xcframework_comment_body(branch_name: branch_name, commit_sha: env.commit_hash)
+  comment_on_pr(
+    project: GITHUB_REPO,
+    pr_number: pr_number,
+    body: body,
+    reuse_identifier: XCFRAMEWORK_COMMENT_REUSE_ID
+  )
+  post_buildkite_annotation(body: body)
+end
+
 lane :xcframework_sign do
   sh(
     'codesign',
@@ -123,3 +155,45 @@ def get_required_env!(key)
 
   UI.user_error!("Environment variable `#{key}` is not set.")
 end
+
+def push_xcframework_snapshot_branch(branch_name:, version:, checksum:)
+  package_swift = File.join(PROJECT_ROOT, 'Package.swift')
+  rewrite_resources_mode!(package_swift, version: version, checksum: checksum)
+
+  sh("git checkout -B #{branch_name}")
+  git_commit(path: package_swift, message: "Update Package.swift for #{version}")
+  sh("git push -f origin #{branch_name}")
+end
+
+def rewrite_resources_mode!(package_swift, version:, checksum:)
+  prefix = 'let resourcesMode: DependencyMode ='
+  replacement = %(#{prefix} .release(version: "#{version}", checksum: "#{checksum}")\n)
+
+  lines = File.readlines(package_swift)
+  matches = lines.count { |line| line.start_with?(prefix) }
+  UI.user_error!("Expected exactly one `#{prefix}` line in Package.swift, found #{matches}") unless matches == 1
+
+  rewritten = lines.map { |line| line.start_with?(prefix) ? replacement : line }
+  File.write(package_swift, rewritten.join)
+end
+
+def xcframework_comment_body(branch_name:, commit_sha:)
+  short_sha = (commit_sha || 'unknown')[0, 8]
+  <<~MARKDOWN
+    ## XCFramework Build
+
+    This PR's XCFramework is available for testing. Add the following to your `Package.swift`:
+
+    ```swift
+    .package(url: "https://github.com/#{GITHUB_REPO}", branch: "#{branch_name}")
+    ```
+
+    <sub>Built from #{short_sha}</sub>
+  MARKDOWN
+end
+
+def post_buildkite_annotation(body:)
+  return unless ENV['BUILDKITE_AGENT_ACCESS_TOKEN']
+
+  buildkite_annotate(context: 'xcframework', style: 'info', message: body)
+end