CORS Checker – Herramienta en línea gratuita – ToolBox
CORS checker en línea gratuito: enter URL, method, headers and body to predict preflight and get common fixes for CORS errors.
CORS checker by ToolBox en línea gratuito: enter an API URL, HTTP method, request headers and body to predict whether the browser will trigger an OPTIONS preflight request, and get actionable fix suggestions for common CORS failures (missing Access-Control-Allow-Origin, methods/headers mismatch, credentials with wildcard origin, and more). Runs fully in-browser; no data is uploaded.