Common Issues
general
API Calls Failing With Errors in My AI App
Your app makes calls to an API (its own backend, Supabase, or a third-party service) and those calls fail. You see errors in the console like 500, 403, 404, or CORS errors.
Error Messages You Might See
CORS policy: No 'Access-Control-Allow-Origin' header
500 Internal Server Error
403 Forbidden
401 Unauthorized
net::ERR_CONNECTION_REFUSED
Timeout: request took too long
Common Causes
- CORS not configured — browser blocks requests from your domain to the API
- API key or auth token expired, missing, or wrong
- API endpoint URL is wrong (still pointing to localhost or old URL)
- Rate limiting — too many requests in a short time
- Backend server error (500) due to unhandled exceptions
How to Fix It
- Open browser Network tab (F12 > Network) and find the failing request — check the status code and response body
- For CORS errors: configure your API server to allow requests from your frontend domain
- For 401/403: check that your API key or auth token is being sent correctly in the request headers
- For 500: check server logs for the actual error — the frontend error won't have details
- For timeouts: check if the API endpoint is accessible from your deployment environment
Real developers can help you.
Anthony Akpan
Developer with 8 years of experience building softwares fro startups
Pratik
SWE with 15+ years of experience building and maintaining web apps and extensive BE infrastructure
prajwalfullstack
Hi Im a full stack developer, a vibe coded MVP to Market ready product, I'm here to help
Nam Tran
10 years as fullstack developer
Mehdi Ben Haddou
- Founder of Chessigma (1M+ users) & many small projects
- ex Founding Engineer @Uplane (YC F25)
- ex Software Engineer @Amazon and @Booking.com
Omar Faruk
As a Product Engineer at Klasio, I contributed to end-to-end product development, focusing on scalability, performance, and user experience.
My work spanned building and refining core features, developing dynamic website templates, integrating secure and reliable payment gateways, and optimizing the overall system architecture.
I played a key role in creating a scalable and maintainable platform to support educators and learners globally.
I'm enthusiastic about embracing new challenges and making meaningful contributions.
Simon A.
I'm a backend developer building APIs, emulators, and interactive game systems. Professionally, I've developed Java/Spring reporting solutions, managed relational and NoSQL databases, and implemented CI/CD workflows.
Antriksh Narang
5 years+ Experienced Dev (Specially in Web Development), can help in python, javascript, react, next.js and full stack web dev technologies.
Basel Issmail
’m a Senior Full-Stack Developer and Tech Lead with experience designing and building scalable web platforms. I work across the full development lifecycle, from translating business requirements into technical architecture to delivering reliable production systems.
My work focuses on modern web technologies, including TypeScript, Angular, Node.js, and cloud-based architectures. I enjoy solving complex technical problems and helping teams turn product ideas and prototypes into working platforms that can grow and scale.
In addition to development, I often collaborate closely with product managers, business analysts, designers, and QA teams to ensure that solutions align with both technical and business goals.
I enjoy working with startups and product teams where I can contribute both as a hands-on engineer and as a technical partner in designing and delivering impactful software.
Dor Yaloz
SW engineer with 6+ years of experience,
I worked with React/Node/Python
did projects with React+Capacitor.js for ios
Supabase expert
Describe what's wrong in plain English. No technical knowledge needed.
Get HelpFrequently Asked Questions
What does a CORS error mean?
CORS (Cross-Origin Resource Sharing) is a browser security feature. It means your frontend (e.g., on Vercel) is trying to call an API on a different domain, and that API hasn't been configured to allow it.
I get a 500 error but don't know what's wrong. How do I find out?
A 500 error means the server crashed. The actual error is in the server logs, not in the browser. Check your hosting platform's logs.