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Create dev and preview builds for your Expo React Native app.

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Build Guidance

To use the Dev Loop, a build is required only on native code changes (new native modules, Podfile/Gradle changes, build configuration). JS/TS changes hot reload via Metro — see Dev Loop: Hot reload and rebuild configuration for the full breakdown.

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Build via Revyl CLI

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Prerequisites

  • Node.js 18+
  • Expo CLI (npx expo)
  • EAS CLI (npx eas-cli) only when your authored recipe uses EAS
  • Revyl CLI installed and authenticated (revyl auth login)

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Setup

Initialize the project using the Revyl CLI:
This detects Expo and writes named profiles with the applicable iOS and Android recipes. Review or fill in the app IDs, commands, and output paths before the first build. See Types of Builds for more information.

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Choose a build approach

Choosing the Expo framework does not itself require EXPO_TOKEN. Add that secret only when the selected build command uses EAS or another project step needs it. The dashboard leaves commands and secret references directly editable; create any required secret inline or in the Library. Development builds power the dev loop. Preview builds are for testing and starting sessions when the Metro server isn’t needed.

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Run Build

Run one profile/platform recipe locally:
Run the same recipe on a Revyl cloud runner by adding --remote:
Profile names and their ios or android recipes live under build.profiles in .revyl/config.yaml. There is no active/default profile. See Configuration for selection and recipe fields. This command automatically builds and uploads the app to Revyl, where you can use it to start sessions.

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Advanced Configuration

When you run revyl init, Revyl makes a best-effort guess at your configuration. This section covers configuration in more detail.

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EAS setup

This section applies only when an authored recipe uses EAS. Your eas.json needs at least two profiles: one that includes the development client and one that does not. See the following eas.json file as reference:
Note that the iOS simulator is enabled for both profiles, and developmentClient is set to true only for the development profile. Revyl executes the command arrays in .revyl/config.yaml as authored; it does not rewrite eas.json or switch EAS profiles during a build.

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Build Commands and Hot Reload Setup

revyl init creates a .revyl/config.yaml file in the root of your project. Each named profile contains the ordered setup/build commands and output path used by revyl build. Configure these build settings using the Configuration page. Expo dev-client hot reload needs a URL scheme baked into the native dev build. This is normally set as part of revyl init. The scheme is the custom URL prefix for your app, such as myapp-dev://. Revyl uses that scheme to open the Expo dev client on the cloud device and connect it to Metro. If you use app.json, set expo.scheme before creating the dev build:

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Troubleshooting

  • Stream detailed diagnostics: revyl build --profile development --platform ios --debug
  • For an unattended remote EAS recipe, verify that EXPO_TOKEN is stored and referenced
  • Check EAS build credits only when the recipe uses EAS
  • Verify package.json dependencies
  • For EAS cloud builds, review the EAS dashboard logs
  • For EAS --local builds, review command output and logs in the local EAS working directory
  • Validate eas.json
  • For iOS, ensure simulator: true is set in eas.json. For Android, ensure the profile builds an apk, not an aab.

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