Edge Functions - Supabase

Edge Functions are server-side TypeScript functions, distributed globally at the edge—close to your users. They can be used for listening to webhooks or integrating your Supabase project with third-parties like Stripe. Edge Functions are developed using Deno, which offers a few benefits to you as a developer:

It is open source.
It is portable. Supabase Edge Functions run locally, and on any other Deno-compatible platform (including self-hosted infrastructure).
It is TypeScript first and supports WASM.
Edge Functions are globally distributed for low-latency.

How it works

Request enters an edge gateway (relay) — the gateway routes traffic, handles auth headers/JWT validation, and applies routing/traffic rules.
Auth & policies are applied — the gateway (or your function) can validate Supabase JWTs, apply rate-limits, and centralize security checks before executing code.
Edge runtime executes your function — the function runs on a regionally-distributed Edge Runtime node closest to the user for minimal latency.
Integrations & data access — functions commonly call Supabase APIs (Auth, Postgres, Storage) or third-party APIs. For Postgres, prefer connection strategies suited for edge/serverless environments (see the connect-to-postgres guide).
Observability and logs — invocations emit logs and metrics you can explore in the dashboard or downstream monitoring (Sentry, etc.).
Response returns via the gateway — the gateway forwards the response back to the client and records request metadata.

Quick technical notes

Runtime: Supabase Edge Runtime (Deno compatible runtime with TypeScript first). Functions are .ts files that export a handler.
Local dev parity: Use Supabase CLI for a local runtime similar to production for faster iteration (supabase functions serve command).
Global deployment: Deploy your Edge Functions via Supabase Dashboard, CLI or MCP.
Cold starts & concurrency: cold starts are possible — design for short-lived, idempotent operations. Heavy long-running jobs should be moved to background workers.
Database connections: treat Postgres like a remote, pooled service — use connection pools or serverless-friendly drivers.
Secrets: store credentials in Supabase project secrets and access them via environment variables.

When to use Edge Functions

Authenticated or public HTTP endpoints that need low latency.
Webhook receivers (Stripe, GitHub, etc.).
On-demand image or Open Graph generation.
Small AI inference tasks or orchestrating calls to external LLM APIs (like OpenAI)
Sending transactional emails.
Building messaging bots for Slack, Discord, etc.

Examples

Check out Supabase Edge Function Examples in GitHub or try these examples: