CORS Tester

Check whether an API's CORS response headers permit a frontend to read a response, with preflight and HTTP status reported separately.

Visit cors-error.dev →

A web tool for testing CORS behavior. It can probe a public API URL through a remote service (Beeceptor), simulating an origin, request method, credentials mode, and request headers, or analyze pasted response and OPTIONS headers locally in the browser. Results show preflight permission, response readability, and actual/OPTIONS HTTP statuses. The remote probe cannot use browser cookies or reach localhost, and results are header-policy predictions rather than proof of browser behavior.

Category: Testing & QA
Pricing: free
Free tier: yes
API: no
MCP server: no
SDK: no
Open source: unknown

#cors #http-headers #preflight #web-development #debugging

Alternatives to CORS Tester →

Listed 2026-10-21 · last verified 2026-10-21 · extracted by @cf/zai-org/glm-5.3-flash · confidence 0.8

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API

curl https://toolgrep.com/api/products/cors-tester