Unable to call Edge Function

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This is a copy of a troubleshooting article on Supabase's docs site. It may be missing some details from the original. View the original article.

If you're having trouble invoking an Edge Function or experiencing CORS issues, follow these steps to diagnose and resolve the problem.

Diagnose the issue

1. Review CORS configuration: Check out the CORS guide and ensure you've properly configured CORS headers
2. Check function logs: Look for errors in Functions > Logs in the dashboard
3. Verify authentication: Confirm JWT tokens and permissions are correct

Proper CORS handling

Make sure your function handles OPTIONS preflight requests.

Recommended (v2.95.0+)

// Recommended approach
import { corsHeaders } from '@supabase/supabase-js/cors' // v2.95.0+

Deno.serve(async (req) => {
  if (req.method === 'OPTIONS') {
    return new Response('ok', { headers: corsHeaders })
  }

  // Your function logic here
  return new Response(JSON.stringify({ status: 'Success' }), {
    headers: { ...corsHeaders, 'Content-Type': 'application/json' },
  })
})

For versions before 2.95.0

If you're using @supabase/supabase-js before v2.95.0, you'll need to hardcode the CORS headers. Add a cors.ts file within a _shared folder:

// _shared/cors.ts
export const corsHeaders = {
  'Access-Control-Allow-Origin': '*',
  'Access-Control-Allow-Headers': 'authorization, x-client-info, apikey, content-type',
}

Then import it in your function:

import { corsHeaders } from '../_shared/cors.ts'

Deno.serve(async (req) => {
  // Handle CORS preflight requests
  if (req.method === 'OPTIONS') {
    return new Response('ok', { headers: corsHeaders })
  }

  // Your function logic here
  return new Response(JSON.stringify({ status: 'Success' }), {
    headers: { ...corsHeaders, 'Content-Type': 'application/json' },
  })
})

Debugging tools

Supabase provides two debugging tools for Edge Functions:

• Invocations: Shows the Request and Response for each execution
• Logs: Shows platform events, including deployments and errors

Access these tools by navigating to Functions > [Your Function] in the dashboard.

Common issues

CORS errors

• Missing Access-Control-Allow-Origin header in response
• Not handling OPTIONS preflight requests
• Mismatched allowed methods or headers

Authentication errors

• Invalid or expired JWT token
• Missing Authorization header
• Incorrect permissions for the authenticated user

Network errors

• Function not deployed
• Incorrect function URL
• Network connectivity issues

Additional resources

• CORS guide
• Edge Functions authentication
• Debugging Edge Functions