Phoenix JSON API

RULES — Follow these with no exceptions

1. Use the :api pipeline — don't mix HTML and JSON pipelines; API routes skip CSRF and sessions
2. Render errors as structured JSON — {:error, changeset} must become {"errors": {...}}
3. Version APIs via URL prefix (/api/v1/) — not headers; URL versioning is visible and cacheable
4. Use FallbackController for consistent error handling — every action returns {:ok, result} or {:error, reason}

Build Workflow

Follow these steps in order when constructing a new API endpoint: