Fix OAuth Errors in Supabase Auth

Updated April 2026

Supabase Auth handles OAuth provider configuration in the dashboard. Errors usually come from missing redirect URLs in your Supabase project settings or incorrect provider app credentials.

Step 1 — Enable the provider in Supabase dashboard

# Supabase Dashboard → Authentication → Providers
# Enable your provider (Google, GitHub, Discord, etc.)
# Enter Client ID and Client Secret from the provider's developer console

Step 2 — Add Site URL and Redirect URLs

# Dashboard → Authentication → URL Configuration

Site URL: https://yourapp.com

Redirect URLs (add ALL your environments): https://yourapp.com/auth/callback https://yourapp.com/** http://localhost:3000/auth/callback http://localhost:3000/**

Step 3 — Add Supabase callback URL to your provider

Supabase has its own callback URL that you must register with the OAuth provider:

# Your Supabase callback URL format:
https://YOUR-PROJECT-REF.supabase.co/auth/v1/callback

# Register this URL in:
# Google: Authorized redirect URIs
# GitHub: Authorization callback URL
# Discord: Redirects

Common error — AuthSessionMissingError

// Fix: ensure you handle the auth callback in your app
// Next.js App Router
// app/auth/callback/route.ts
import { createRouteHandlerClient } from "@supabase/auth-helpers-nextjs";
import { cookies } from "next/headers";
import { NextResponse } from "next/server";

export async function GET(request: Request) { const { searchParams } = new URL(request.url); const code = searchParams.get("code"); if (code) { const supabase = createRouteHandlerClient({ cookies }); await supabase.auth.exchangeCodeForSession(code); } return NextResponse.redirect(new URL("/dashboard", request.url));
}

Common error — redirect URL not allowed

# Error: "Redirect URL not allowed"
# Fix: Add the URL to Redirect URLs in Supabase dashboard
# Dashboard → Authentication → URL Configuration → Redirect URLs

# Add wildcard for development:
http://localhost:3000/**

# Add specific path for production:
https://yourapp.com/auth/callback

Supabase OAuth in your frontend

import { createClient } from "@supabase/supabase-js";

const supabase = createClient(SUPABASE_URL, SUPABASE_ANON_KEY);

// Trigger OAuth flow
const { error } = await supabase.auth.signInWithOAuth({ provider: "google", options: { redirectTo: "https://yourapp.com/auth/callback", },
});