Best way to provision external (MongoDB) user records on Supabase Auth user creation?

[Shreedhar73]

We use MongoDB as our primary database and maintain a _user collection that stores all application-specific user data.

We plan to use Supabase strictly for authentication (Google, Apple, Email) and not use Supabase Postgres for application data. MongoDB will remain the only source of truth for user records.

On successful user creation in Supabase Auth, we want to automatically create a corresponding _user document in MongoDB.

Constraints / Requirements

• Supabase is used only for authentication
• MongoDB is the only database for user data
• We support multiple clients (Web + Mobile)
• We want to avoid client-driven user provisioning
• User creation should be server-side, deterministic, and idempotent
• We do not want to couple MongoDB with Supabase Postgres

Current Limitation Observed

After exploring the platform, it appears that:

• Supabase does not currently provide native HTTP webhooks for auth lifecycle events (e.g. user.created)
• Supabase Auth Hooks cannot trigger Edge Functions
• Auth Hooks are limited to internal auth behavior and cannot call external services

Because of this, Supabase cannot proactively notify an external backend (e.g. AWS Lambda) when a user is created.

Question

Given the above constraints and limitations:

• What is the recommended or idiomatic way to provision user records in an external database (MongoDB) when using Supabase for auth only?
• Are there any plans to support auth lifecycle webhooks or Edge Function triggers for auth events in the future?

[Shreedhar73]

Okay, Current Solution :

• On user creation, a data is added to auth.users automatically
• Created a Database Web-hook, on inserts to auth.users , and created user on mongodb.