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CORS Debugger

Why won’t my CORS work? Compare your failing request with a controlled second origin to narrow down where the problem is.

Find out why your CORS request is failing

Tell us where the request starts and what API it is trying to reach. AnotherExample will build two browser tests: your real API request and a controlled comparison against our second origin.

1

What are you testing?

Tell us where the browser request starts and what API or resource it is trying to reach.

We’ll identify the browser origin automatically.
The API/resource your page is trying to reach. Test A uses this URL exactly as entered.
2

Describe the request

Match the request that is giving you trouble. These settings are used for both diagnostic tests.

POST/PUT uses Content-Type: application/json, which normally triggers a browser preflight.

3Controlled comparison — optional settings

AnotherExample uses a controlled second origin as a working baseline. These optional settings affect that comparison only; they do not change your Target API.

AnotherExample does not crawl, proxy, or modify either URL. The generated tests run in your browser from your own page, where CORS is actually enforced.

NEXT STEP

What did your browser say?

Paste the error or result from your browser Console. AnotherExample will explain what it recognizes and what to check next.

This first version recognizes common browser and CORS messages without guessing when the cause is unclear.

Preview environment: control requests use cors-preview.anotherexample.com. Production will use cors.anotherexample.com.

EXPLORE

Explore common CORS failures

Want to see what a browser CORS failure actually looks like? These presets intentionally change AnotherExample’s controlled endpoint to reproduce common successes and failures.

This is separate from diagnosing your own target.

Scenario: None selected

Expected browser result

Choose a scenario or use your current settings.

Scenario endpoint