CORS for Sanity

medium4 checks

CORS decides which origins may read your API responses. A wildcard turns an authenticated API into a public one.

What Sanity must have

  • Access-Control-Allow-Origin limited to known origins
  • No wildcard combined with credentials
  • No reflection of arbitrary Origin headers
  • Preflight responses only allow the methods actually used

How to fix it

  1. 1Replace wildcards with an explicit allowlist
  2. 2Validate Origin before echoing it and reject unknown origins early

Sanity context

Headless CMS with real-time content APIs.

Datasets can be public or private: verify the dataset ACL before publishing a token.