Lovable deployment

CORS Error in Production Blocking Supabase Requests

API requests to Supabase fail with CORS error in production. 'Access-Control-Allow-Origin' header missing or not matching domain. Works locally but fails on deployed site.

CORS policy requires server to explicitly allow requests from client domain. Browser blocks cross-origin requests without proper headers.

Error Messages You Might See

Access-Control-Allow-Origin header is missing CORS policy blocked request The value of the Access-Control-Allow-Origin is not a match
Access-Control-Allow-Origin header is missingCORS policy blocked requestThe value of the Access-Control-Allow-Origin is not a match

Common Causes

  1. Supabase project not configured to allow production domain
  2. Using wrong domain in CORS settings (www vs non-www)
  3. Production domain not in Supabase allowed origins list
  4. Missing API key or using wrong key tier
  5. localhost still in allowed origins blocking production domain

How to Fix It

In Supabase dashboard > Project Settings > API > CORS config, add your production domain:

https://yourdomain.com
https://www.yourdomain.com
http://localhost:5173

Use exact domains. Wildcards not allowed. Redeploy after updating.

Real developers can help you.

Matthew Butler Matthew Butler Systems Development Engineer @ Amazon Web Services Yovel Cohen Yovel Cohen I got a lot of experience in building Long-horizon AI Agents in production, Backend apps that scale to millions of users and frontend knowledge as well. PawelPloszaj PawelPloszaj I'm fronted developer with 10+ years of experience with big projects. I have small backend background too BurnHavoc BurnHavoc Been around fixing other peoples code for 20 years. Mehdi Ben Haddou Mehdi Ben Haddou - Founder of Chessigma (1M+ users) & many small projects - ex Founding Engineer @Uplane (YC F25) - ex Software Engineer @Amazon and @Booking.com Rudra Bhikadiya Rudra Bhikadiya I build and fix web apps across Next.js, Node.js, and DBs. Comfortable jumping into messy code, broken APIs, and mysterious bugs. If your project works in theory but not in reality, I help close that gap. Nam Tran Nam Tran 10 years as fullstack developer Matt Butler Matt Butler Software Engineer @ AWS ISHANTDEEP SINGH 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 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

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Frequently Asked Questions

Do I need CORS in development?

No, Supabase allows localhost origins by default. Only needed for production domains.

Should I use wildcard CORS?

No, specify exact domains for security. Supabase does not support wildcard origins.

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