2xx Success:

• 200 OK: Successful GET, PUT, PATCH
• 201 Created: Successful POST
• 204 No Content: Successful DELETE or PUT with no response body

4xx Client Error:

• 400 Bad Request: Invalid request syntax
• 401 Unauthorized: Authentication required
• 403 Forbidden: Access denied
• 404 Not Found: Resource doesn't exist
• 409 Conflict: Resource conflict
• 422 Unprocessable Entity: Validation errors

5xx Server Error:

• 500 Internal Server Error: Generic server error
• 503 Service Unavailable: Server temporarily unavailable