Discover / cors-header-checker.underscoredone.com

CORS Header Checker

■ Challenge detected

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 origin is permitted, and shows every permission value exactly as the server sent it. Useful for finding why a browser is blocking a request, confirming a new deployment is configured correctly, or auditing whether a public API allows credentialed calls.

x402
Base
Solana
USDC

Listed price: $0.01
Challenge detected: 10 of the last 10 checks
Median response: 114 ms
Last checked: 17 Oct, 08:59 UTC
In our index since: 26 Sept 2026

Endpoint

curl -i https://cors-header-checker.underscoredone.com/check
# 402 Payment Required: pay with an x402 client (USDC on Base),
# then send the same request again with the payment attached.

1 listed endpoints · on x402 Bazaar

Checks and payment terms on this page refer to the endpoint above. Other listed endpoints have not been checked individually.

POSThttps://cors-header-checker.underscoredone.com/check$0.01Sends 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 origin is permitted, and shows every permission value exactly as the server sent it. Useful for finding why a browser is blocking a request, confirming a new deployment is configured correctly, or auditing whether a public API allows credentialed calls.

A dash means the listing gives no price or method. Copy buttons copy the full URL.

Showing 1 of 1 listed endpoints.

Agents can find it through the Superstables MCP server and JSON API: GET /api/v1/services/cors-header-checker.underscoredone.com

Recent checks

28 Sept 2026One bar per check, showing up to 20 recent checks. Coloured bars show relative response time, with a minimum visible height; full-height grey bars mean no challenge was detected. “Challenge detected” means HTTP 402 or another detected payment-challenge signal.17 Oct 2026

All 10 checks

When (UTC)	Result	HTTP	Response
17 Oct, 08:59 UTC	Challenge detected	402	207ms
16 Oct, 08:13 UTC	Challenge detected	402	206ms
14 Oct, 23:56 UTC	Challenge detected	402	75ms
13 Oct, 20:45 UTC	Challenge detected	402	100ms
11 Oct, 19:34 UTC	Challenge detected	402	98ms
10 Oct, 03:32 UTC	Challenge detected	402	79ms
8 Oct, 21:32 UTC	Challenge detected	402	123ms
7 Oct, 15:42 UTC	Challenge detected	402	133ms
6 Oct, 15:31 UTC	Challenge detected	402	122ms
28 Sept, 17:02 UTC	Challenge detected	402	106ms

Questions

Did our last probe detect a payment challenge?

At our last probe on 17 Oct, 08:59 UTC, it returned HTTP 402 or another detected payment-challenge signal. This check did not test payment, delivery or compatibility with the Superstables client.

What price is recorded for CORS Header Checker?

Its listed price is $0.01.

What payment terms does CORS Header Checker advertise?

The listing advertises x402, Base, Solana and USDC. It names cdp as its facilitator. Check the seller's current payment challenge and authentication requirements before paying.

Where is CORS Header Checker listed?

In x402 Bazaar. Superstables first indexed it on 26 Sept 2026.

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