Preview Deployments

Preview deployments give every pull request its own live URL, so your team can review changes before merging to production.

How it works

When you enable the catch-all environment for a project, Stackpad automatically creates a preview deployment for any branch that doesn’t match an existing environment.

For example, if your default environment is main:

• Push to main → deploys to production
• Push to feature/new-login → creates a preview
• Push to fix/header-bug → creates a separate preview
• Merge the PR and delete the branch → preview is cleaned up automatically

Enabling preview deployments

1. Go to Project Settings
2. Toggle Automatic preview deploys (or go to Environments → Add Environment and enable Build feature branches)
3. That’s it — push to any branch and Stackpad creates a preview

You can only have one catch-all environment per project.

What happens when a preview is created

When you push to a branch that doesn’t match any existing environment, Stackpad:

1. Creates a new environment named after the branch
2. Clones all services from your default (production) environment
3. Creates separate containers for each cloned service — including databases and caches
4. Sets up a new private network for the preview environment
5. Builds and deploys the web services from the pushed branch

Each preview environment is a complete, isolated copy of your production stack.

Resource usage

Each preview creates full copies of all services — including databases and caches. If your project has a web service, PostgreSQL, and Redis, each preview branch gets its own web container, its own PostgreSQL instance, and its own Redis instance.

This means:

• Resource usage scales with the number of active preview branches
• Plan limits apply — each preview’s services count toward your organization’s service limits
• Preview databases start empty — they don’t have production data

Keep your active branches lean. Merge or delete branches you’re no longer working on.

Preview URLs

Preview deployments are accessible at:

https://your-project-branch-name.your-org.stackpad.eu

The branch name is slugified:

• Lowercase
• Special characters (slashes, underscores) replaced with hyphens
• Leading and trailing hyphens removed

Branch name	Preview URL
feature/new-login	your-project-feature-new-login.your-org.stackpad.eu
fix/header_bug	your-project-fix-header-bug.your-org.stackpad.eu
v2	your-project-v2.your-org.stackpad.eu

Automatic cleanup

When a branch is deleted on GitHub (typically after merging a pull request), Stackpad receives a webhook and automatically:

1. Stops all containers in the preview environment
2. Removes the Caddy routes
3. Cleans up the preview environment

No manual cleanup needed. If you delete the branch locally but not on GitHub, the preview stays running until the branch is deleted from GitHub.

Note

Previews persist indefinitely as long as the branch exists on GitHub. There is no automatic timeout. If you have long-lived feature branches, the preview continues running (and consuming resources) until the branch is deleted.

Environment variables in previews

Preview environments inherit project-level environment variables. They do not inherit environment-level variables from production — those are scoped to the production environment only.

If your previews need different values (e.g. a separate third-party API key for testing), set them as environment-level variables on the preview environment after it’s created.

What’s next?

• Git push deploy — understand the full deployment pipeline
• Environment variables — how variable scoping works across environments
• Rollbacks — zero-downtime deploys and debugging failures