Replit api

CORS Credentials and Cookies Not Sent

Authenticated API requests fail because cookies aren't sent. CORS blocks credentials even after preflight succeeds.

Credentials mode and CORS headers must align for cookies to transmit.

Error Messages You Might See

Credentials mode is 'include' but Access-Control-Allow-Credentials header is missing Access-Control-Allow-Origin cannot use wildcard
Credentials mode is 'include' but Access-Control-Allow-Credentials header is missingAccess-Control-Allow-Origin cannot use wildcard

Common Causes

  1. Client not sending credentials: 'include' in fetch
  2. Server not sending Access-Control-Allow-Credentials: true
  3. Access-Control-Allow-Origin set to * (incompatible with credentials)
  4. Cookie SameSite=Strict blocking cross-site cookies

How to Fix It

Client: fetch(url, { credentials: 'include' }). Server: response header Access-Control-Allow-Credentials: true. Set Access-Control-Allow-Origin to specific domain, NOT *. Ensure cookies have SameSite=None; Secure for cross-site. Configure Spring CORS with allowedOriginPatterns and allowCredentials=true.

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Frequently Asked Questions

How do I send cookies with fetch?

fetch(url, { credentials: 'include' }) - must also set server headers correctly

Can I use Access-Control-Allow-Origin: *?

Not with credentials. Use specific domain or null for local testing

Related Replit Issues

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