Errors and limits

Every error is JSON. Most carry a human-readable detail; where an agent needs to branch on the cause, there is also a stable code.

Status	code	Meaning	What to do
400	—	The request body is invalid; the body names each failing field	Fix the named fields and resend
400	—	A lesson edit did not send updated_at	Read the lesson, send its updated_at with your change
401	—	No key, or the key is unknown, revoked or expired (Authentication credentials were not provided.)	Check the Authorization header; ask for a new key
401	subscription_inactive	The organisation has no active paid plan	A person must subscribe to a plan
401	org_unverified	The organisation has not completed verification	A person must finish sign-up
403	—	The key's permission for this area is too low	Ask for view or edit on that area (permissions)
403	course_limit	Creating a course would exceed the plan's course limit; detail says by how much	Archive a finished course, or a person moves to a larger plan
404	—	Nothing with that id in this key's organisation	Check the id; keys only ever see their own organisation
409	stale_lesson	The lesson changed since you read it; lesson holds the current version	Re-apply your change to lesson and resend with its updated_at
429	—	Rate limit reached	Wait Retry-After seconds

Limits

• 300 requests per hour per key. Each key has its own allowance.
• Plan limits apply exactly as in the web app — for example, the number of courses on your plan. Creating one past the limit is refused with 403 course_limit.
• Keys can expire. If a person set an expiry date, the key stops working at that date with 401.