Preview Builds on PRs

// eas.json - preview profile
{
  "build": {
    "preview": {
      "distribution": "internal",
      "channel": "preview",
      "android": { "buildType": "apk" },
      "ios": { "simulator": false }
    }
  }
}

# .github/workflows/preview-pr.yml
name: Preview Build
on:
  pull_request:
    types: [labeled]
 
jobs:
  preview:
    if: contains(github.event.pull_request.labels.*.name, 'needs-preview')
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: expo/expo-github-action@v8
        with:
          eas-version: latest
          token: ${{ secrets.EXPO_TOKEN }}
      - run: npm ci
      - id: build
        run: |
          eas build --profile preview --platform android --non-interactive --json > build.json
          echo "url=$(jq -r '.[0].artifacts.buildUrl' build.json)" >> $GITHUB_OUTPUT
      - uses: actions/github-script@v7
        with:
          script: |
            github.rest.issues.createComment({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              body: `## 📱 Preview build\n\nInstall: ${{ steps.build.outputs.url }}\n\nScan QR on device or open link.`
            })

your-expo-app/
  .github/workflows/preview-pr.yml
  .eas/workflows/preview-pr.yml   # optional EAS-native alternative
  eas.json
  app.json

{
  "build": {
    "preview": {
      "distribution": "internal",
      "channel": "preview",
      "env": {
        "APP_VARIANT": "preview"
      },
      "android": {
        "buildType": "apk"
      },
      "ios": {
        "simulator": false
      }
    },
    "preview-simulator": {
      "distribution": "internal",
      "ios": { "simulator": true },
      "android": { "buildType": "apk" }
    }
  }
}

// app.config.ts - optional variant banner
const IS_PREVIEW = process.env.APP_VARIANT === "preview";
 
export default {
  expo: {
    name: IS_PREVIEW ? "MyApp (Preview)" : "MyApp",
    // ...
  },
};

name: Preview on PR
on:
  pull_request:
    types: [opened, synchronize, labeled]
 
concurrency:
  group: preview-${{ github.event.pull_request.number }}
  cancel-in-progress: true
 
jobs:
  preview:
    if: contains(github.event.pull_request.labels.*.name, 'needs-preview')
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with: { node-version: 20, cache: npm }
      - uses: expo/expo-github-action@v8
        with:
          eas-version: latest
          token: ${{ secrets.EXPO_TOKEN }}
      - run: npm ci
      - run: npm run typecheck
      - name: EAS preview build
        id: eas
        run: |
          eas build \
            --profile preview \
            --platform android \
            --non-interactive \
            --json > build-output.json
          BUILD_URL=$(jq -r '.[0].artifacts.buildUrl // .artifacts.buildUrl' build-output.json)
          QR_URL=$(jq -r '.[0].artifacts.applicationArchiveUrl // empty' build-output.json)
          echo "build_url=$BUILD_URL" >> $GITHUB_OUTPUT
      - name: Comment on PR
        uses: actions/github-script@v7
        with:
          script: |
            const url = '${{ steps.eas.outputs.build_url }}';
            const body = [
              '## 📱 Android preview build',
              '',
              `**Install:** ${url}`,
              '',
              '1. Open the link on your Android device',
              '2. Scan the QR code or download the APK',
              '3. Allow install from unknown sources if prompted (internal testing only)',
              '',
              '_Built from commit `${{ github.sha }}` with profile `preview`._'
            ].join('\n');
            github.rest.issues.createComment({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              body
            });

# .eas/workflows/preview-pr.yml
name: Preview PR
on:
  pull_request:
    types: [labeled]
 
jobs:
  quality:
    if: ${{ github.event.pull_request.labels.*.name contains 'needs-preview' }}
    steps:
      - uses: eas/checkout
      - uses: eas/install_node_modules
      - run: npm run typecheck
 
  build_preview:
    needs: [quality]
    type: build
    params:
      platform: android
      profile: preview

npx eas-cli@latest workflow:run .eas/workflows/preview-pr.yml

# Label-gated (recommended)
if: contains(github.event.pull_request.labels.*.name, 'needs-preview')
 
# Path-filter - native-impacting changes only
on:
  pull_request:
    paths:
      - "app/**"
      - "src/**"
      - "app.config.ts"
      - "plugins/**"

## Preview builds
Add label `needs-preview` when QA or design needs a device build.
Do **not** add for copy-only or test-only changes.

eas update --channel preview --message "PR-${{ github.event.pull_request.number }}"

  maestro_smoke:
    needs: [build_preview]
    type: maestro
    params:
      build_id: ${{ needs.build_preview.outputs.build_id }}
      flow_path: [".maestro/smoke.yml"]