Supabase Edge Functions errorSupabase: “Edge Function returned a non-2xx status code”

How to find the real error

1. 01

   The real error is in error.context

   “FunctionsHttpError: Your function executed but returned an error (4xx/5xx status)” Supabase, Edge Functions: Error handling

   Check which kind of error you got, and for a FunctionsHttpError, read the body the function sent back. This is Supabase’s example:

   import { FunctionsFetchError, FunctionsHttpError, FunctionsRelayError } from '@supabase/supabase-js'
   
   const { data, error } = await supabase.functions.invoke('hello', {
     headers: { 'my-custom-header': 'my-custom-header-value' },
     body: { foo: 'bar' },
   })
   
   if (error instanceof FunctionsHttpError) {
     const errorMessage = await error.context.json()
     console.log('Function returned an error', errorMessage)
   } else if (error instanceof FunctionsRelayError) {
     console.log('Relay error:', error.message)
   } else if (error instanceof FunctionsFetchError) {
     console.log('Fetch error:', error.message)
   }

2. 02

   The function’s logs say what failed

   “You can see the production error logs in the Logs tab of your Supabase Dashboard.” Supabase, Edge Functions: Error handling

   Open the function in the dashboard and read its logs around the time of the failed call. Errors the function logs with console.error appear there; if it logs nothing, add logging around the step that fails.

3. 03

   Every problem comes back as a 500

   “Return 400 for bad user input, 404 when something doesn't exist, 500 for server errors, etc.” Supabase, Edge Functions: Error handling

   If the function returns 500 for everything, the app can’t tell a bad form value from a crash. Return the right status with a JSON body that carries a message, so the app can show people something useful.

4. 04

   A relay or fetch error is a different problem

   “FunctionsFetchError: Function couldn't be reached at all” Supabase, Edge Functions: Error handling

   If the error is a FunctionsRelayError or FunctionsFetchError instead, the function didn’t answer with its own error. We check the function name, that it is deployed, and the network before touching the function’s code.

Checked against the vendor’s docs on November 1, 2026: Supabase docs: Edge Functions error handling.

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