Fastlane

Fastlane automates the release chores of mobile apps: building, managing certificates, bumping build numbers, taking screenshots and uploading to the stores. You describe each workflow as a lane in a Ruby file called a Fastfile, then run it locally or in CI.

platform :ios do
  lane :beta do
    match(type: "appstore")
    increment_build_number(xcodeproj: "ios/MyApp.xcodeproj")
    build_app(workspace: "ios/MyApp.xcworkspace", scheme: "MyApp")
    upload_to_testflight
  end
end

Each line is an action, and the common ones carry older short names you will still see in guides: build_app (gym), upload_to_testflight (pilot), upload_to_app_store (deliver) and upload_to_play_store (supply).

The piece React Native teams value most is match. It stores your iOS certificates and provisioning profiles, encrypted, in a private Git repository or cloud bucket, and installs them on any machine that runs the lane. That removes "it only signs on Dave’s laptop" from your team, which is the core problem of iOS code signing on CI.

Where it fits today: if you use EAS Build, you mostly do not touch fastlane directly; EAS manages credentials and runs the iOS build steps for you. Bare React Native projects building on their own runners, or teams that need custom release steps, still rely on it heavily.

Practical gotchas:

• It is a Ruby gem, so pin it in a Gemfile and run bundle exec fastlane to avoid "works on my machine" version drift.
• Authenticate with an App Store Connect API key rather than an Apple ID, which runs into two-factor prompts on CI.
• match nuke revokes every certificate of a type for the whole team. Read the prompt twice.

See the fastlane docs.