Recipe: Cloudflare Workers

Setup

// src/db/schemas.ts
import { defineSchema, s } from "mondel";

export const userSchema = defineSchema("users", {
  timestamps: true,
  fields: {
    email: s.string().required().email(),
    name: s.string(),
  },
});

export const schemas = [userSchema] as const;

// src/db/client.ts
import { createClient, type SchemasToClient } from "mondel";
import { schemas } from "./schemas";

export type DbClient = SchemasToClient<typeof schemas>;

// Module scope: cheap factory, no TCP yet
export const connect = createClient({
  serverless: true,
  schemas,
  validation: "strict",
});

// src/index.ts
import { connect } from "./db/client";

export interface Env {
  MONGODB_URI: string;
}

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const db = await connect(env.MONGODB_URI, { maxPoolSize: 5 });
    try {
      if (request.method === "GET") {
        const users = await db.users.findMany({}, { limit: 50 });
        return Response.json(users);
      }
      return new Response("Method not allowed", { status: 405 });
    } finally {
      await db.close();
    }
  },
};

Practices

1. Keep the factory at module scope; connect inside fetch.
2. Pass URI from secrets/bindings, never hardcode.
3. Prefer Atlas with SRV strings.
4. Push indexes from CI, not from the Worker.
5. Tune maxPoolSize for your concurrency and Atlas tier.

Related

• Client & Connections
• Compatibility