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revyl dev runs your local app on a cloud iOS simulator or Android emulator. You keep editing code in your own workspace. Revyl provisions the device, installs your development build, starts hot reload, and opens a live viewer. For Expo and React Native, most JavaScript and TypeScript changes hot reload through Metro. For other stacks, Revyl rebuilds and reinstalls when a change needs a new binary.

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Before you start

  • The Revyl CLI, signed in with revyl auth login.
  • A development build uploaded to a Revyl app. For iOS that’s a simulator .app or a zipped .app, not an .ipa. For Android it’s a debuggable APK whose native libraries include x86_64 or arm64-v8a. See Artifact requirements.
  • A terminal in your app’s directory, the one that holds the mobile project.
1

Set up the project

This writes .revyl/config.yaml with a stable project.id. When detection works, it also writes build.framework and named iOS and Android profiles. If it picked a nested native project, run revyl init --detect from the app directory, adjust the profile, and run revyl config validate.
2

Start the loop

Revyl starts your dev server, installs the branch’s development build, and opens the live viewer in your browser. Add --profile <name> if your project has more than one development profile, or --build-version-id <id> to install a specific build.
3

Make a change

Save a file. Expo and React Native changes reload through Metro. For native changes, trigger a rebuild and wait for it:
4

Check the result

Drive the device from a second terminal while the loop runs:
Work in small steps: look at the screen, take one action, confirm it did what you expected.
Stop the loop with revyl dev stop.

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Run the loop in the background

Coding agents and scripts should start the loop detached and read its state as JSON:
--detach returns once the device session is ready and prints the handshake with --json. The build keeps running behind it.

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Build native iOS changes remotely

--remote builds native iOS changes on a Revyl build runner instead of your machine. Add --seed-latest to install your branch’s latest build right away, then swap in the fresh build when it lands.

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Attach to a session someone already started

If a teammate or agent already has the right device state open from the dashboard, attach your local loop to it instead of starting over:

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Sign in early

If your app needs an account, decide how the loop reaches a signed-in state before you start debugging: a test account with seeded data, a staging-only demo mode, or a test-only auth bypass deep link. If the app logs out mid-session while the boot token is still valid, revyl dev auth refresh fires the deep link again.

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Troubleshooting

For framework-specific errors, see Dev loop framework troubleshooting.

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Good to know

  • Dev contexts are per worktree, so separate worktrees each get their own loop without --context.
  • The device stops after 300 seconds idle. Change that with --timeout.
  • revyl dev never stores an active profile or platform. Explicit flags win; otherwise it uses the only development-like profile it finds.
  • Every flag is listed in the revyl dev reference.