D1 example

This tutorial builds a Worker that creates a table, inserts one row per request, and returns the row count from native SQLite.

Prerequisites

• Install Peren so peren is on your PATH
• An empty project directory

Create the files

Create worker.js:

export default {
  async fetch(_request, env) {
    await env.DB.exec("create table if not exists visits (id integer primary key)");
    await env.DB.prepare("insert into visits default values").run();
    const row = await env.DB.prepare("select count(*) as count from visits").first();
    return Response.json({ provider: env.DB.provider.kind, ...row });
  },
};

Create peren.toml:

[node]
node_id = "00000000-0000-0000-0000-000000000001"
advertise_addr = "127.0.0.1:7000"
listen = "127.0.0.1:7000"

[bucket]
kind = "memory"

[mtls]
ca_cert_path = "./certs/ca.pem"
leaf_cert_path = "./certs/leaf-cert.pem"
leaf_key_path = "./certs/leaf-key.pem"

[[services]]
name = "api"
worker_bundle_path = "worker.js"
compatibility_date = "2026-01-01"

[services.bindings.DB]
type = "d1_database"
database_name = "app"
unique_key = "app"

[[sockets]]
name = "public"
listen = "127.0.0.1:8080"
service = "api"

Omit backend to use native_sqlite.

Run

peren devcert ./certs
peren dev peren.toml

peren dev binds loopback listeners on port 0 and uses a memory bucket for the session. Call the public: URL it prints. 54321 below stands for that port.

curl http://127.0.0.1:54321/
curl http://127.0.0.1:54321/

Expected JSON on the first request:

{"provider":"native_sqlite","count":1}

Expected JSON on the second request:

{"provider":"native_sqlite","count":2}

Failure

If worker_bundle_path points at a missing file, Peren refuses to start and reports that the Worker module could not be read. Create worker.js, then run peren dev peren.toml again.

Next

Statement methods, Turso credentials, and refused backends: D1.