CORS Header Configurator

The CORS Configuration Generator builds a matching set of Cross-Origin Resource Sharing snippets for five platforms at once: an Nginx add_header block with a proper origin whitelist map and preflight handler, an Apache .htaccess version using SetEnvIf and mod_headers, a dependency-free Express middleware, a plain PHP header() snippet, and a Next.js next.config.js headers() entry. Enter your allowed origins one per line, tick the HTTP methods, edit the allowed and exposed header lists, choose a preflight max-age, and toggle credentials — the tool validates every origin, echoes only whitelisted origins back, and refuses the invalid combination of credentials with a wildcard origin.

CORS errors are among the most common and most misunderstood problems in web development, and most fixes pasted from forums simply allow everything. This free tool by Hosting Cambodia gives developers and sysadmins in Phnom Penh, Siem Reap, and across Cambodia and beyond a safe, correct whitelist configuration for APIs consumed by separate frontends, complete with a short explanation of how the browser preflight actually works. Copy the snippet for your stack and reload — the same settings produce identical behaviour on every platform.