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CORS Tester
Test and analyze CORS configurations. A browser-based developer tool that runs entirely client-side — no data is sent to our servers.
Use CORS Tester now
Requires Dev-Belt Pro ($12/month or $99/year). Unlocks all 246 tools.
What it does
The CORS Tester is designed for developers who need to test and analyze cors configurations quickly and accurately, without setting up local tools or depending on third-party services.
Whether you're working in networking / http or integrating it into a broader development pipeline, this tool saves time and reduces the risk of manual errors. All processing runs in your browser — your data never leaves your machine.
- ► Security audits and penetration testing preparation
- ► Learning about web application security vulnerabilities
Key features
- ✓Origin, method, and header configuration analysis
- ✓Simple vs preflight request detection
- ✓Access-Control-* header generation
- ✓Common CORS misconfiguration warnings
- ✓Wildcard vs specific origin comparison
How to use it
- Open CORS Tester by clicking on it in the Dev-Belt dashboard.
- Sign in and upgrade to Pro to unlock this tool ($12/month or $99/year).
- Enter your input in the provided fields — all processing happens instantly in your browser.
- Copy the output using the Copy button, or paste it directly into your project.
When to use this in your project
Security audit preparation
Run your inputs through security scanners to find obvious vulnerabilities before a formal pentest.
Developer security training
Understand what XSS, SQL injection, and other attacks look like by testing with real examples in a safe environment.
Code review
Paste suspicious input patterns to check if they trigger known attack signatures before merging a PR.
Developer notes
!Never set Access-Control-Allow-Origin: * on endpoints that require authentication.
!Preflight OPTIONS requests must return 204 or 200 — many CORS bugs come from missing OPTIONS handling.
!CORS is enforced by the browser only — it does not protect your API from server-side requests or curl.
Privacy & Security
All Dev-Belt tools run 100% in your browser using client-side JavaScript. Your input data is never sent to our servers, never logged, and never stored. This includes code snippets, credentials, tokens, API keys, and any other sensitive information you enter. We only track authentication events for account management — never tool usage, search queries, or input data.
Related keywords
corshttpapisecurity
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246 Developer Tools — One Dashboard
CORS Tester is one of 246 browser-based tools on Dev-Belt. Free tools work instantly — no account required. Pro unlocks the full suite at $12/month.