Developer Tool
CORS Preflight Doctor
Diagnose CORS preflight issues and get minimal server fixes for your API requests
Request Configuration
Configure your request and click "Analyze CORS"
Get instant diagnosis and server fixes
How CORS Works
Simple Requests
- Methods: GET, HEAD, POST
- Simple content types only
- No custom headers
- No preflight required
Preflight Requests
- Custom methods (PUT, DELETE, etc.)
- JSON content type
- Authorization headers
- OPTIONS request sent first
Changelog
v1.0.0Latest
Initial Release
- • CORS preflight detection and analysis
- • Server-side fix generation (Express, Nginx, Spring)
- • Credential and header validation
- • Real-time error diagnosis
- • Copy-paste server configurations
- • Privacy-first browser-only processing
Advertisement
Quick Tips
- All processing happens in your browser
- Your data never leaves your device
- No registration or login required
Advertisement