# GitHub Preview Deployments Source: https://next.coolify.io/docs/applications/sources/github/preview-deploy Preview deployments run pull requests separately from the production application. Coolify removes an automatic preview after its pull request is merged or closed. ## Features ### Preview domains ![Preview URL Template and Load Pull Requests controls in Coolify](https://next.coolify.io/docs/images/applications/ci-cd/github/preview-deploy/4.webp) **Preview URL Template** controls the generated domain: * `{{random}}` inserts a random value. * `{{pr_id}}` inserts the pull-request number. > **Warning: Create wildcard DNS first** > > To use a domain such as `https://123.preview.example.com`, create an `A` or `AAAA` record for `*.preview.example.com` that points to the deployment server. **Load Pull Requests** fetches currently open pull requests. > **Info: Deploy older pull requests manually** > > Coolify does not automatically deploy pull requests that were already open when preview deployments were enabled. Select **Load Pull Requests**, then select **Deploy** for each required pull request. ### Choose who can deploy previews Pull-request code can be untrusted. A public contributor could otherwise run code on your server. ![Preview Deployments and Allow Public PR Deployments settings](https://next.coolify.io/docs/images/applications/ci-cd/github/preview-deploy/1.webp) * **Preview Deployments** enables previews for trusted repository members, collaborators, and contributors. * **Allow Public PR Deployments** allows public contributors to trigger previews. Keep public pull-request deployments disabled unless you accept the risk of running contributor code. ### Scoped secrets Coolify keeps production and preview variables separate. ![Production and preview environment-variable groups](https://next.coolify.io/docs/images/applications/ci-cd/github/preview-deploy/2.webp) * **Production Environment Variables** are used only by the main deployment and are not passed to pull-request previews. * **Preview Deployment Environment Variables** are used only by pull-request deployments. Do not copy production credentials into preview variables for untrusted pull requests. Use limited, non-production credentials. ### Automated comments Coolify can add deployment status and domain information to the pull request and update the comment when the deployment state changes. ![Coolify preview deployment comment on a GitHub pull request](https://next.coolify.io/docs/images/applications/ci-cd/github/preview-deploy/3.webp) > **Info: Comments require a GitHub App** > > Manual repository webhooks can trigger previews, but automated pull-request comments require GitHub App permissions. *** ## Set up preview deployments Choose how the application receives pull-request events. **GitHub App** Follow [Set up a GitHub App](https://next.coolify.io/docs/applications/sources/github/app) first. **Automated installation** ![Preview Deployments permission during automated GitHub App installation](https://next.coolify.io/docs/images/applications/ci-cd/github/preview-deploy/github-app/1.webp) Set **Preview deployment access** to **Read and update pull requests** before selecting **Register with GitHub**. Coolify requests read-and-write pull-request access and subscribes the app to pull-request events. **Manual installation** ![Pull Request permission during manual GitHub App creation](https://next.coolify.io/docs/images/applications/ci-cd/github/preview-deploy/github-app/2.webp) When creating the app on GitHub: 1. Set **Pull requests** to **Read and write** under **Repository permissions**. 2. Subscribe to the **Pull request** event. ### Update an existing GitHub App ![Update GitHub App permissions action in Coolify](https://next.coolify.io/docs/images/applications/ci-cd/github/preview-deploy/github-app/3.webp) 1. Open **Sources** and select the GitHub App. 2. Open **Permissions**. 3. Select **Update**. ![Pull Request permissions and event subscription on GitHub](https://next.coolify.io/docs/images/applications/ci-cd/github/preview-deploy/github-app/4.webp) 4. Set **Pull requests** to **Read and write**. 5. Subscribe to **Pull request** events. 6. Accept the permission update. **Repository webhook** ![GitHub manual webhook URL and secret in Coolify](https://next.coolify.io/docs/images/applications/ci-cd/github/preview-deploy/webhook/1.webp) 1. Open **Webhooks**. 2. Enter a random **Webhook secret** in the **GitHub** section and select **Save changes**. 3. Copy the GitHub URL under **Manual Git webhooks**. > **Warning: Protect the webhook secret** > > The secret authenticates webhook deliveries. Use the same value in Coolify and GitHub. ![Webhooks page in GitHub repository settings](https://next.coolify.io/docs/images/applications/ci-cd/github/preview-deploy/webhook/2.webp) 4. Open the repository settings on GitHub. 5. Select **Webhooks > Add webhook**. ![GitHub webhook configured for pull-request events](https://next.coolify.io/docs/images/applications/ci-cd/github/preview-deploy/webhook/3.webp) 6. Paste the Coolify URL into **Payload URL**. 7. Enter the same secret. 8. Keep **Enable SSL verification** selected. 9. Choose **Let me select individual events**. 10. Select **Pull requests**. 11. Keep **Active** selected. 12. Select **Add webhook**. ![Active pull-request webhook in GitHub](https://next.coolify.io/docs/images/applications/ci-cd/github/preview-deploy/webhook/4.webp) *** ## Verify preview deployments 1. Open or update a pull request. 2. Confirm that Coolify creates a separate preview deployment. 3. Open the generated preview domain and test the changed behavior. 4. Close the pull request and confirm that Coolify removes the automatic preview.