> ## Documentation Index
> Fetch the complete documentation index at: https://www.towbar.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Cloud Native Buildpacks

> Build source with pinned pack and builder images.

Choose `buildpack` when the project follows the Cloud Native Buildpacks model. Pin both `packImage` and `builder` to digests, select a source context, and use `project.toml` only when project-specific buildpack settings are needed.

## Example manifest

This is the validated example from the Towbar `examples/platform-modes` project. Replace the documentation IP and project paths with values for your environment. `builder` must be one of Towbar's reviewed Paketo or Heroku digests; an arbitrary digest-pinned builder will fail validation.

```yaml title=".towbar/apps/buildpack.app.yml" theme={"system"}
id: buildpack-example
name: Cloud Native Buildpacks example
deployment:
  type: buildpack
  context: examples/platform-modes/node-app
  packImage: buildpacksio/pack@sha256:a53c4d6c297e10e680404cffda32e557b79a26d1ee4b7e6b18c0d175cb274621
  builder: heroku/builder@sha256:84d80b3c0d242961414a3c4d0a00c3518e6de01ef936423cfbaf1b0aa0f9155c
  configFile: project.toml
  architecture: amd64
  cache:
    enabled: true
    scope: platform-buildpack-example
container:
  port: 3000
health:
  path: /health
environments:
  production:
    server: 192.0.2.10
```

## Configure it

The example uses an amd64 builder, a bounded context, and a workload cache. Keep the approved `builder` digest or choose another from the [app schema](/schemas/app.v2.json). `packImage` is a separate, digest-pinned pack CLI image. Validate the resulting image's process and health behavior before adding public routing.

Buildpacks reject build secrets. If the build needs credentials, use a Dockerfile and a protected BuildKit secret mount instead.

Map the named environment to a branch, register and prepare its server, then sync the repository. Start with a manual deployment and verify the running service before opting into automation. See [Application manifest](/docs/apps/manifest) for shared fields and [Deployment modes](/docs/platform-deployments) to compare modes.