Errors

Rejected requests return JSON problem details (application/problem+json).

Shape

{
  "type": "https://api.cotes.ai/problems/unauthorized",
  "title": "Unauthorized",
  "status": 401,
  "detail": "Missing or invalid API key."
}

type is a stable https://api.cotes.ai/problems/{slug} URI — match on it rather than on detail.

Common status codes

Status	type slug	When
401	unauthorized	Missing or invalid API key
404	not-found	Unknown ticker, or no live contest for the series
422	—	Missing or empty series — see below
429	rate-limited	Throttled — see Rate limits
5xx	—	Transient server error — retry with backoff

Malformed requests

A missing or empty series, and any unknown path, are rejected before the API’s own error handling and come back as plain application/json in the framework’s shape — no type, no title:

{ "detail": [{ "type": "missing", "loc": ["query", "series"], "msg": "Field required" }] }

Branch on the status code and the Content-Type rather than assuming every failure carries a type.

Successful responses are application/json. See the API reference for per-operation responses.