CORS Header Checker
Sends a real request to any URL you provide, attaches an Origin header, and reads back all six standard cross-origin permission headers the server returns. Tells you whether cross-origin requests are enabled at all, whether your specific or
Go to this service →Our latest check (2026-10-11)
- Answering
- Yes — valid x402 payment terms
- Time to answer
- 1184 ms
- Price
- $0.010 per call
- Paying buyers, last 30 days
- 4 (directory's own records)
- Paid calls, last 30 days
- 5
- Category
- Unclassified
- Address
- https://cors-header-checker.underscoredone.com/check
Accuracy
Accuracy scores are published once a seller has enough paid checks against an independent record (at least 7 scored answers over at least 7 days). Until then no score is shown, and a missing score is never a pass.
For agents
This page as JSON: /sellers/fe77862dfd3e.json. Paid lookup by address: GET /api/seller?resource=… ($0.001, x402).