Begin with the supported development source. These are source-development instructions, not a public production installation procedure.

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Prerequisites

Use the Node.js and package-manager versions declared by the selected release. The inspected development checkout declares bun@1.4.0 and a Bun lockfile; installing an arbitrary npm dependency tree does not reproduce that environment. Follow the checkout’s README for OS prerequisites and native dependencies.

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Setup and start

After obtaining that source and installing its matching dependencies, its root scripts include:
The setup helper configures the development environment. The dev script serves the frontend, API, engine and worker packages. Use the URL printed by the frontend process; do not assume a fixed port when another preview is already running. The renamed reference interface for this guide runs on port 4201. The documentation preview runs separately on port 4174. Use only the synthetic development account supplied or seeded by the source setup; those credentials are not a customer account or a production sign-in method.

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Pieces Development

AP_DEV_PIECES chooses the local integrations built for development. In a compatible checkout, a source-development example is:
Check the selected release’s implementation of AP_PIECES_SYNC_MODE and local package resolution. External catalog synchronization and local development bundles are different paths. Keep package names and versions aligned with the SDK.

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Custom Code

The current fork’s Code sandbox requires a Deno executable configured through AP_DENO_PATH in the runtime executing the step. Check that prerequisite before a Code test; an actual development test failed without it. Do not change sandbox isolation to work around a missing binary. Verify a built-in action, your gadget’s authentication, error behavior and output on the matching application before release. A running frontend alone does not establish that the execution runtime is configured.