Generate correct CORS headers — Access-Control-Allow-Origin, methods, headers, credentials. Fix preflight failures with exact syntax — local generation, free, no signup.
Content reviewed October 2026 · About Toolzum
Generate Nginx server blocks — reverse proxy, SSL, gzip, caching headers — without syntax hunting. Ship a correct vhost first try — local generation, free, no signup.
Run a real CORS preflight from your browser — a cross-origin request that shows whether an endpoint allows it, with the exact server headers to confirm.
Generate CSS transforms — rotate, scale, skew, translate — with live preview. Build hover effects without guessing syntax — local generation, free, no signup.
Generate valid robots.txt with user-agents, allows, disallows, and sitemap lines. Never accidentally deindex with Disallow: / — local generation, free, no signup.
Generate random MAC addresses for labs and testing — pure random hex, no OUI or unicast-bit management. Fill virtual networks credibly — local generation, free, no signup.
The server lacks Access-Control-Allow-Origin for your origin, or preflight (OPTIONS) fails on methods/headers. Generate the exact header set and compare against live response headers.
Wildcard (*) is simple but forbids credentials; specific origins pair with Allow-Credentials for cookies. Authenticated APIs need the specific form.
Access-Control-Max-Age caches preflights (86400s typical) to cut OPTIONS chatter. Set it once the policy stabilizes.
No — generation runs locally in your browser. Nothing leaves your device.