Build Nango Functions

Build Nango action and sync implementations without choosing the execution workflow.

This skill covers the function design contract: schemas, provider calls, action outputs, sync models, checkpoints, deletion handling, metadata, retries, and runtime constraints. It intentionally does not cover local CLI validation/deploy or remote API compile/dryrun/deploy.

If the task becomes clearly local/CLI-based, use building-nango-functions-locally instead. If it becomes clearly remote/API-based, use building-nango-functions-remotely instead.

Implementation Scope

• Build or modify a Nango function implementation
• Build an action in Nango with createAction()
• Build a sync in Nango with createSync()
• Use the active workflow skill for compile, dryrun, test, and deploy mechanics

Sync Strategy Gate (required before writing code)

If the task is a sync, read references/syncs.md before writing code and state one of these paths first: