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.

Real developers can help you.

Vlad Temian Vlad Temian 15+ years shipping production infrastructure for startups. Former CTO at qed.builders (acquired by The Sandbox). Cursor ambassador and agentic tooling builder. I've scaled systems, automated deployments, and built observability tools for AI coding workflows. I specialize in taking vibe-coded apps from broken prototype to production-ready: fixing Supabase auth/RLS, Stripe integrations, deployment pipelines, and cleaning up AI-generated spaghetti. I build tools in this space (agentprobe, claudebin, micode) and understand both sides: how AI generates code and why it breaks. https://blog.vtemian.com/ Luca Liberati Luca Liberati I work on monoliths and microservices, backends and frontends, manage K8s clusters and love to design apps architecture Jared Hasson Jared Hasson Full time lead founding dev at a cyber security saas startup, with 10 yoe and a bachelor's in CS. Building & debugging software products is what I've spent my time on for forever Meïr Ankri Meïr Ankri Full-stack developer specializing in React / Next.js / Node.js with 6+ years of experience. I've worked across various sectors including automotive (Reezocar/Société Générale), healthcare (Medical Link SaaS), and e-commerce (Glasman). I build web apps end-to-end, from architecture to production, with a focus on scalability, performance, and code quality. I also mentor junior developers and contribute to technical decisions and code reviews. zipking zipking I am a technologist and product builder dedicated to creating high-impact solutions at the intersection of AI and specialized markets. Currently, I am focused on PropScan (EstateGuard), an AI-driven SaaS platform tailored for the Japanese real estate industry, and exploring the potential of Archify. As an INFJ-T, I approach development with a "systems-thinking" mindset—balancing technical precision with a deep understanding of user needs. I particularly enjoy the challenge of architecting Vertical AI SaaS and optimizing Small Language Models (SLMs) to solve specific, real-world business problems. Whether I'm in a CTO-level leadership role or hands-on with the code, I thrive on building tools that turn complex data into actionable value. Prakash Prajapati Prakash Prajapati I’m a Senior Python Developer specializing in building secure, scalable, and highly available systems. I work primarily with Python, Django, FastAPI, Docker, PostgreSQL, and modern AI tooling such as PydanticAI, focusing on clean architecture, strong design principles, and reliable DevOps practices. I enjoy solving complex engineering problems and designing systems that are maintainable, resilient, and built to scale. Sage Fulcher Sage Fulcher Hey I'm Sage! Im a Boston area software engineer who grew up in South Florida. Ive worked at a ton of cool places like a telehealth kidney care startup that took part in a billion dollar merger (Cricket health/Interwell health), a boutique design agency where I got to work on a ton of exciting startups including a photography education app, a collegiate Esports league and more (Philosophie), a data analytics as a service startup in Cambridge (MA) as well as at Phillips and MIT Lincoln Lab where I designed and developed novel network security visualizations and analytics. I've been writing code and furiously devoted to using computers to make people’s lives easier for about 17 years. My degree is in making computers make pretty lights and sounds. Outside of work I love hip hop, the Celtics, professional wrestling, magic the gathering, photography, drumming, and guitars (both making and playing them) Matthew Butler Matthew Butler Systems Development Engineer @ Amazon Web Services Richard McSorley Richard McSorley Full-Stack Software Engineer with 8+ years building high-performance applications for enterprise clients. Shipped production systems at Walmart (4,000+ stores), Cigna (20M+ users), and Arkansas Blue Cross. 5 patents in retail/supply chain tech. Currently focused on AI integrations, automation tools, and TypeScript-first architectures. Costea Adrian Costea Adrian Embedded Engineer specilizing in perception systems. Latest project was a adas camera calibration system.

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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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