What is CORS Policy?
Server-side rules that control which web origins can make cross-domain HTTP requests.
Definition
A CORS policy is the set of HTTP response headers a server sends to control cross-origin access. Key headers include Access-Control-Allow-Origin (which domains can access), Access-Control-Allow-Methods (which HTTP methods are permitted), Access-Control-Allow-Headers (which request headers are allowed), and Access-Control-Max-Age (how long preflight results are cached). CORS policies are enforced by browsers only — server-to-server requests like cron jobs are not affected.
Simple Analogy
Like a guest list at an exclusive event — the server decides in advance which domains (guests) are welcome, what they can do (methods), and what they can bring (headers).
Why It Matters
While CORS does not affect CronJobPro server-to-server requests, it is critical when building web dashboards that interact with your cron job APIs from the browser. Misconfigured CORS policies cause confusing errors — the API works perfectly from curl but fails from your web app. Understanding CORS saves hours of debugging.
How to Verify
Open browser developer tools, go to the Network tab, and look for failed requests with CORS errors in the Console. Check your API server response headers for Access-Control-Allow-Origin. Test preflight requests with curl to verify the OPTIONS response includes correct CORS headers. Use browser extensions to temporarily bypass CORS for debugging (never in production).
Common Mistakes
Using "Access-Control-Allow-Origin: *" with credentials (browsers reject this combination). Not handling OPTIONS preflight requests. Setting CORS headers only on some routes, causing inconsistent behavior. Confusing CORS errors with actual server errors — CORS blocks are client-side, the server processed the request fine.
Best Practices
Configure CORS to allow only your specific frontend domains. Never use wildcard (*) origins in production when credentials are involved. Handle OPTIONS requests explicitly. Cache preflight responses with appropriate Max-Age to reduce OPTIONS request overhead. Remember: CORS only applies to browsers — your CronJobPro jobs are unaffected.
Security Documentation
Read security docs
Try it free →Frequently Asked Questions
What is CORS Policy?
A CORS policy is the set of HTTP response headers a server sends to control cross-origin access. Key headers include Access-Control-Allow-Origin (which domains can access), Access-Control-Allow-Methods (which HTTP methods are permitted), Access-Control-Allow-Headers (which request headers are allowed), and Access-Control-Max-Age (how long preflight results are cached). CORS policies are enforced by browsers only — server-to-server requests like cron jobs are not affected.
Why does CORS Policy matter for cron jobs?
While CORS does not affect CronJobPro server-to-server requests, it is critical when building web dashboards that interact with your cron job APIs from the browser. Misconfigured CORS policies cause confusing errors — the API works perfectly from curl but fails from your web app. Understanding CORS saves hours of debugging.
What are best practices for CORS Policy?
Configure CORS to allow only your specific frontend domains. Never use wildcard (*) origins in production when credentials are involved. Handle OPTIONS requests explicitly. Cache preflight responses with appropriate Max-Age to reduce OPTIONS request overhead. Remember: CORS only applies to browsers — your CronJobPro jobs are unaffected.
Related Terms
CORS
Cross-Origin Resource Sharing, a browser security policy governing cross-domain HTTP requests.
Content Security Policy (CSP)
An HTTP header that prevents XSS and injection attacks by controlling allowed content sources.
Request Header
Key-value metadata sent with an HTTP request to provide context like authentication and content type.
HTTP Method
The verb (GET, POST, PUT, DELETE, etc.) that defines the type of action an HTTP request performs.
Endpoint
A specific URL where an API or service receives and processes HTTP requests.