Deno Runtime

The Deno backend runs functions in the Supabase edge-runtime — a Deno-based container that supports TypeScript, npm packages, fetch(), WebAssembly, and more.

tip

deno is effectively a special case of the HTTP runtime with a single, global upstream (EDGE_RUNTIME_URL). For a new polyglot function — or when you want each function in its own container — prefer runtime='http'.

Setup

Add the edge-runtime service to your docker-compose.yml:

edge-runtime:
  image: supabase/edge-runtime:v1.62.2
  environment:
    PGSTACK_DB_URL: postgres://postgres:postgres@db:5432/app
  volumes:
    - ./supabase/functions:/functions:ro
  depends_on:
    db:
      condition: service_healthy

Tell the proxy where to find it:

proxy-go:
  environment:
    EDGE_RUNTIME_URL: http://edge-runtime:9000

Writing functions

Functions live in supabase/functions/{name}/index.ts:

Deno.serve(async (req: Request) => {
  // Access auth headers injected by the proxy
  const role = req.headers.get('x-pgstack-role');
  const claims = JSON.parse(req.headers.get('x-pgstack-claims') || '{}');

  // Call external APIs
  const res = await fetch('https://api.example.com/data');
  const externalData = await res.json();

  // Access the database
  const dbUrl = Deno.env.get('PGSTACK_DB_URL');

  return new Response(
    JSON.stringify({ role, externalData }),
    { headers: { "Content-Type": "application/json" } },
  );
});

Deploy

export SERVICE_ROLE_KEY=<your-service-role-key>   # or pass --service-role-key <key>
pgstack functions deploy my-function --runtime deno

This registers the function in pgstack.edge_functions and refreshes the proxy's catalog. The edge-runtime picks up function files from the mounted volume.

Deploy registers the function via the proxy's POST /api/sql endpoint, so the proxy must be running with ENABLE_SQL_ENDPOINT=true (the dev docker-compose.yml sets it; it is false by default and should stay disabled in production).

Features

• Full TypeScript support
• fetch() for external API calls
• npm packages via import maps
• WebAssembly support
• Environment variables via Deno.env
• Database access via PGSTACK_DB_URL