CORS Misconfiguration in Lovable App
Your Lovable app either blocks legitimate requests with CORS errors or is configured with overly permissive CORS settings (Access-Control-Allow-Origin: *) that allow any website to make requests to your API.
CORS errors appear as failed API calls in the browser console, preventing your app from communicating with its backend or third-party services. On the other hand, wildcard CORS settings mean any malicious website could make requests to your API on behalf of your users.
This commonly happens when your frontend and backend are on different domains, or when Lovable generates API routes without proper CORS configuration.
Error Messages You Might See
Common Causes
- Wildcard origin allowed — The API is configured with Access-Control-Allow-Origin: * which is insecure for authenticated endpoints
- Missing CORS headers — The backend doesn't include the necessary CORS headers, blocking frontend requests
- Credentials with wildcard — Trying to send cookies/auth headers with a wildcard CORS policy, which browsers block
- Preflight request failing — OPTIONS requests are not handled, causing complex requests (POST with JSON) to fail
- Different domains in production — Frontend and API are on different domains but CORS is only configured for localhost
How to Fix It
- Set specific allowed origins — Replace wildcard (*) with your actual frontend domain(s)
- Handle OPTIONS preflight — Make sure your server responds to OPTIONS requests with proper CORS headers
- Allow credentials properly — If using cookies/auth, set Access-Control-Allow-Credentials: true with a specific origin (not wildcard)
- Configure allowed methods and headers — Explicitly list the HTTP methods and headers your frontend needs
- Test with browser DevTools — Check the Network tab for failed preflight requests and missing headers
Real developers can help you.
Vlad Temian
15+ years shipping production infrastructure for startups. Former CTO at qed.builders (acquired by The Sandbox).
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Pratik
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Richard McSorley
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As a Product Engineer at Klasio, I contributed to end-to-end product development, focusing on scalability, performance, and user experience.
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ISHANTDEEP SINGH
Senior Software Engineer with 7+ years of experience in React, JavaScript, TypeScript, Next.js, and Node.js. I’ve also worked as a tech lead for startups, owning end-to-end technical execution including architecture, development, scaling, and delivery. I bring a strong mix of hands-on coding, product thinking, and technical leadership, and I’m comfortable building products from scratch as well as improving and scaling existing systems.
Dor Yaloz
SW engineer with 6+ years of experience,
I worked with React/Node/Python
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Get HelpFrequently Asked Questions
What is CORS and why does it exist?
CORS (Cross-Origin Resource Sharing) is a browser security feature that prevents websites from making requests to a different domain than the one that served the page. It protects users from malicious sites making unauthorized API calls.
Is it safe to use Access-Control-Allow-Origin: * ?
Only for public APIs that don't use authentication. For any API that handles user data or requires login, you must specify exact allowed origins.