diff --git a/.buildkite/commands/build-and-upload-testflight.sh b/.buildkite/commands/build-and-upload-testflight.sh
new file mode 100755
index 000000000000..ee7d80b718bb
--- /dev/null
+++ b/.buildkite/commands/build-and-upload-testflight.sh
@@ -0,0 +1,17 @@
+#!/bin/bash -eu
+
+# Builds one app and uploads it to TestFlight for internal testers.
+#
+# Part of the "Faster Releases for WordPress and Jetpack" RFC. CI runs one
+# invocation per app (in parallel) via the matrix step in pipeline.yml.
+
+APP="${1:?Usage: build-and-upload-testflight.sh <wordpress|jetpack|reader>}"
+
+"$(dirname "${BASH_SOURCE[0]}")/shared-set-up.sh"
+"$(dirname "${BASH_SOURCE[0]}")/shared-set-up-distribution.sh"
+
+echo "--- :closed_lock_with_key: Installing Secrets"
+bundle exec fastlane run configure_apply
+
+echo "--- :hammer_and_wrench: Building and uploading ${APP} to TestFlight"
+bundle exec fastlane build_and_upload_app_for_testflight app:"${APP}"
diff --git a/.buildkite/pipeline.yml b/.buildkite/pipeline.yml
index bad262059d14..908500740d53 100644
--- a/.buildkite/pipeline.yml
+++ b/.buildkite/pipeline.yml
@@ -31,6 +31,32 @@ steps:
           - github_commit_status:
               context: "Jetpack Prototype Build"
 
+  #################
+  # Continuous Delivery: build & upload each app to TestFlight (internal testers)
+  #
+  # Part of the "Faster Releases for WordPress and Jetpack" RFC. On every trunk
+  # commit, each app builds and uploads to TestFlight in parallel via the matrix
+  # below. Gated to trunk so it doesn't run on PR branches.
+  #################
+  - group: ":testflight: TestFlight Builds"
+    key: testflight_builds_group
+    steps:
+      - label: ":testflight: Build & Upload {{matrix}}"
+        command: ".buildkite/commands/build-and-upload-testflight.sh {{matrix}}"
+        plugins: [$CI_TOOLKIT_PLUGIN]
+        if: "build.branch == 'trunk'"
+        matrix:
+          - "wordpress"
+          - "jetpack"
+          # Reader is omitted: its App Store archive has been broken since #25321
+          # (PostHelper moved to the app target without updating the Reader target),
+          # and went undetected after #25179 removed Reader from CI. Re-add once
+          # the Reader target archives again.
+          # - "reader"
+        notify:
+          - github_commit_status:
+              context: "TestFlight Build ({{matrix}})"
+
   #################
   # Create Builds for Testing
   #################
diff --git a/fastlane/lanes/build.rb b/fastlane/lanes/build.rb
index 4eaee5ccb4dd..07e8f8c9b787 100644
--- a/fastlane/lanes/build.rb
+++ b/fastlane/lanes/build.rb
@@ -314,6 +314,116 @@
     end
   end
 
+  # Builds a single app and uploads it to TestFlight for *internal* testers,
+  # stamping the build code with the Buildkite build number.
+  #
+  # This is the per-commit "continuous delivery" build from the "Faster Releases
+  # for WordPress and Jetpack" RFC. It is intentionally additive: the existing
+  # release lanes are untouched and remain the source of truth until this flow
+  # is proven.
+  #
+  # The marketing version (`VERSION_SHORT`) is read from `Version.public.xcconfig`
+  # as-is. The build code is `<marketing version>.0.<buildkite build number>`
+  # (e.g. `27.0.0.4567`). Buildkite build numbers increase monotonically, so each
+  # build for a given marketing version gets a unique, higher build code — which
+  # is all App Store Connect requires.
+  #
+  # "Internal-only" means no external groups and no external-tester notifications
+  # (matching the existing Reader upload). Distributing to the a8c staff beta
+  # group, and separately to the public beta group, is wired up in later phases
+  # of the RFC.
+  #
+  # @param [String] app One of `wordpress`, `jetpack`, or `reader`.
+  #
+  # @called_by CI
+  #
+  desc 'Builds one app and uploads it to TestFlight for internal testers'
+  lane :build_and_upload_app_for_testflight do |app:|
+    app = app.to_s.downcase
+
+    case app
+    when 'wordpress'
+      scheme = 'WordPress'
+      output_name = APP_STORE_CONNECT_BUILD_NAME_WORDPRESS
+      beta_app_description_path = WORDPRESS_BETA_APP_DESCRIPTION_PATH
+      sentry_project_slug = SENTRY_PROJECT_SLUG_WORDPRESS
+      app_identifier = WORDPRESS_BUNDLE_IDENTIFIER
+      update_certs_and_profiles_wordpress_app_store
+    when 'jetpack'
+      scheme = 'Jetpack'
+      output_name = APP_STORE_CONNECT_BUILD_NAME_JETPACK
+      beta_app_description_path = JETPACK_BETA_APP_DESCRIPTION_PATH
+      sentry_project_slug = SENTRY_PROJECT_SLUG_JETPACK
+      app_identifier = JETPACK_BUNDLE_IDENTIFIER
+      update_certs_and_profiles_jetpack_app_store
+    when 'reader'
+      scheme = 'Reader'
+      output_name = APP_STORE_CONNECT_BUILD_NAME_READER
+      beta_app_description_path = BETA_APP_DESCRIPTION_PATH_READER
+      sentry_project_slug = nil # Reader does not have a Sentry project yet
+      app_identifier = nil
+      update_certs_and_profiles_app_store_reader
+    else
+      UI.user_error!("Unknown app '#{app}'. Expected one of: wordpress, jetpack, reader")
+    end
+
+    build_number = ENV.fetch('BUILDKITE_BUILD_NUMBER', nil)
+    UI.user_error!('BUILDKITE_BUILD_NUMBER is not set — this lane is meant to run on CI') if build_number.nil?
+
+    build_code = "#{release_version_current}.0.#{build_number}"
+    UI.important("Building #{scheme} #{release_version_current} (#{build_code}) for internal TestFlight distribution")
+
+    sentry_check_cli_installed
+
+    build_app(
+      scheme: scheme,
+      workspace: WORKSPACE_PATH,
+      clean: true,
+      output_directory: BUILD_PRODUCTS_PATH,
+      output_name: output_name,
+      derived_data_path: DERIVED_DATA_PATH,
+      export_team_id: get_required_env('EXT_EXPORT_TEAM_ID'),
+      xcargs: { VERSION_LONG: build_code },
+      export_options: { **COMMON_EXPORT_OPTIONS, method: 'app-store' }
+    )
+
+    upload_app_to_testflight_internal(
+      ipa_path: lane_context[SharedValues::IPA_OUTPUT_PATH],
+      beta_app_description_path: beta_app_description_path
+    )
+
+    # Upload symbols so crashes from these builds symbolicate in Sentry.
+    next if sentry_project_slug.nil?
+
+    sentry_debug_files_upload(
+      auth_token: get_required_env('SENTRY_AUTH_TOKEN'),
+      org_slug: SENTRY_ORG_SLUG,
+      project_slug: sentry_project_slug,
+      path: lane_context[SharedValues::DSYM_OUTPUT_PATH]
+    )
+
+    upload_gutenberg_sourcemaps(
+      sentry_project_slug: sentry_project_slug,
+      release_version: release_version_current,
+      build_version: build_code,
+      app_identifier: app_identifier
+    )
+  end
+
+  # Convenience wrapper that builds and uploads each app to TestFlight, one after
+  # another. CI builds each app in parallel via a Buildkite matrix instead; this
+  # lane is handy for running the whole set locally.
+  #
+  # Reader is omitted until its App Store archive is fixed (broken since #25321).
+  # The per-app lane still supports `app: 'reader'`; just re-add it here once it builds.
+  #
+  desc 'Builds and uploads WordPress and Jetpack to TestFlight (internal)'
+  lane :build_all_apps_for_testflight do
+    %w[wordpress jetpack].each do |app|
+      build_and_upload_app_for_testflight(app: app)
+    end
+  end
+
   # Builds the WordPress app for a Prototype Build ("WordPress Alpha" scheme), and uploads it to Firebase App Distribution
   #
   # @called_by CI
@@ -426,6 +536,33 @@ def upload_build_to_testflight(ipa_path:, whats_new_path:, distribution_groups:,
     )
   end
 
+  # Uploads an already-built IPA to TestFlight for internal testers only.
+  #
+  # @param [String] ipa_path Path to the built IPA.
+  # @param [String] beta_app_description_path Path to the beta app description file.
+  #
+  def upload_app_to_testflight_internal(ipa_path:, beta_app_description_path:)
+    # TBD (RFC D4): the "what's new" text for per-commit internal builds is not
+    # finalized yet. For now, generate a minimal placeholder from the commit
+    # metadata so the upload has something to show. Public-beta builds will get
+    # richer notes generated from the PRs merged since the previous public build.
+    changelog = "Automated build from `#{ENV.fetch('BUILDKITE_BRANCH', 'unknown')}` (#{ENV.fetch('BUILDKITE_COMMIT', 'unknown')[0...7]})."
+    whats_new_path = File.join(Dir.tmpdir, 'testflight_whats_new.txt')
+
+    begin
+      File.write(whats_new_path, changelog)
+
+      upload_build_to_testflight(
+        ipa_path: ipa_path,
+        whats_new_path: whats_new_path,
+        distribution_groups: [], # Internal-only for now (RFC D2): no external groups.
+        beta_app_description_path: beta_app_description_path
+      )
+    ensure
+      FileUtils.rm_rf(whats_new_path)
+    end
+  end
+
   # Send a Slack message to the specified channel
   #
   # @param [String] message The message to send to the channel