CORS Rule Builder
Network & Ops · Free Online Tool
Generate CORS response headers (Access-Control-*).
Access-Control-Allow-Origin: https://example.com Access-Control-Allow-Methods: GET, POST Access-Control-Allow-Headers: Content-Type, Authorization Access-Control-Max-Age: 86400
All CORS Headers
Generates Allow-Origin, Methods, Headers, Expose, Credentials, and Max-Age.
Pre-flight Ready
Output works for both simple requests and OPTIONS pre-flight responses.
Export
Copy or download headers for use in Nginx, Express, or Apache configs.
How to Use CORS Rule Builder
- 1Enter the URL, IP address, or network parameter to look up.
- 2Click the lookup or test button.
- 3Review the detailed results in the output panel.
- 4Use the information for your network operations.
Features
- ✓100% free — no signup, no subscription, no ads
- ✓Runs entirely in your browser — data never leaves your device
- ✓Fast and lightweight — instant results
- ✓Cross-platform — works on desktop, tablet, and mobile
Frequently Asked Questions
Are network lookups real-time?
Yes, IP lookups, DNS queries, and HTTP tests perform live network requests to provide current data.
Is my IP address logged?
The IP Lookup tool queries public geolocation APIs. We do not store your IP address or lookup history.
Why do geolocation results differ between providers?
Each provider maintains its own IP-to-location database with different update cycles and coverage. Treat any single result as an approximation, not an exact address.
Do the results reflect me if I use a proxy or VPN?
No. Results show the egress IP of the proxy or VPN you are connected through. Disconnect it if you need your real public IP.
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