Trigger a GitHub Actions Workflow Across Repositories

Use `repository_dispatch` to trigger a workflow in a target repository when commits or PRs land in a source repository.

GitHub Actions workflows are scoped to a single repository by default. To run a workflow in another repository after merging a PR or pushing a commit, use GitHub's `repository_dispatch` API endpoint.

1. Configure the Target Repository Listener

Add `repository_dispatch` to the `on` block in the target repository workflow file:

# .github/workflows/build.yml (target repo)
name: Build Site

on:
  push:
    branches:
      - main
  repository_dispatch:
    types: [content-updated]
  workflow_dispatch:

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: echo "Build triggered"

2. Configure the Source Repository Dispatcher

In the source repository, add a workflow step that sends a POST request to GitHub's dispatches endpoint:

# .github/workflows/notify.yml (source repo)
name: Notify Target Repo

on:
  push:
    branches:
      - main

jobs:
  notify:
    runs-on: ubuntu-latest
    steps:
      - name: Trigger target build
        env:
          TOKEN: ${{ secrets.WEBSITE_DISPATCH_TOKEN }}
        run: |
          if [ -z "$TOKEN" ]; then
            echo "WEBSITE_DISPATCH_TOKEN is not set"
            exit 1
          fi
          curl --fail --show-error -X POST \
            -H "Authorization: Bearer $TOKEN" \
            -H "Accept: application/vnd.github.v3+json" \
            https://api.github.com/repos/OWNER/TARGET-REPO/dispatches \
            -d '{"event_type": "content-updated"}'

3. Create and Assign the Access Token

1. Create a Fine-Grained Personal Access Token under GitHub Developer Settings.
2. Select the target repository under Repository Access.
3. Set Contents permission to Read and write.
4. Save the token as WEBSITE_DISPATCH_TOKEN in the source repository's Actions Secrets.

Key Considerations

• The event_type string in the payload must match the array value under types: [...].
• Always pass --fail --show-error to curl so HTTP errors exit with code 1 instead of failing silently.
• Fine-grained tokens limit dispatch access strictly to the targeted repository.