Fix: Supabase Storage Upload Returns Error
Quick Answer
Check your storage bucket policies in Supabase Dashboard > Storage > Policies. The most common issue is missing an INSERT policy on the storage.objects table for authenticated users.
Quick Fix Summary
| Issue | File upload failing |
| Fastest fix | Create storage bucket policies |
| Use this page if | Error: new row violates row-level security policy for storage.objects |
Symptoms
- !Error: new row violates row-level security policy for storage.objects
- !Upload returns 403 Forbidden
- !File uploads work locally but fail in production
- !Large files fail but small files work
Step-by-Step Fix
Create storage bucket policies
Go to Supabase Dashboard > Storage > your bucket > Policies. Add policies for INSERT (upload), SELECT (download), DELETE. Example INSERT policy: (auth.uid() IS NOT NULL) for authenticated uploads.
Check file size limits
Free tier allows files up to 50MB. Check your bucket's file size limit in Storage > Configuration. For larger files, upgrade your plan or use multipart upload.
Verify MIME types
If you restricted allowed MIME types on the bucket, ensure the uploaded file type is in the list. Common mistake: allowing 'image/jpeg' but not 'image/jpg'.
Use the correct upload method
Use supabase.storage.from('bucket-name').upload('path/file.jpg', file, { contentType: file.type }). Always include contentType to prevent MIME type errors.
Frequently Asked Questions
Local development often bypasses RLS. In production, you need explicit storage policies. Check the Policies tab on your storage bucket.
Free plan: 50MB per file, 1GB total storage. Pro plan: 5GB per file, 100GB total storage.
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