--- title: Deploy an Express.js application on Cloudflare Workers description: Learn how to deploy an Express.js application on Cloudflare Workers. image: https://developers.cloudflare.com/dev-products-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/workers/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) ### Tags [ TypeScript ](https://developers.cloudflare.com/search/?tags=TypeScript) # Deploy an Express.js application on Cloudflare Workers **Last reviewed:** 7 months ago In this tutorial, you will learn how to deploy an [Express.js ↗](https://expressjs.com/) application on Cloudflare Workers using the [Cloudflare Workers platform](https://developers.cloudflare.com/workers/) and [D1 database](https://developers.cloudflare.com/d1/). You will build a Members Registry API with basic Create, Read, Update, and Delete (CRUD) operations. You will use D1 as the database for storing and retrieving member data. ## Before you start All of the tutorials assume you have already completed the [Get started guide](https://developers.cloudflare.com/workers/get-started/guide/), which gets you set up with a Cloudflare Workers account, [C3 ↗](https://github.com/cloudflare/workers-sdk/tree/main/packages/create-cloudflare), and [Wrangler](https://developers.cloudflare.com/workers/wrangler/install-and-update/). ## Quick start If you want to skip the steps and get started quickly, select **Deploy to Cloudflare** below. [![Deploy to Cloudflare](https://deploy.workers.cloudflare.com/button)](https://deploy.workers.cloudflare.com/?url=https://github.com/cloudflare/docs-examples/tree/main/workers/express-on-workers) This creates a repository in your GitHub account and deploys the application to Cloudflare Workers. Use this option if you are familiar with Cloudflare Workers, and wish to skip the step-by-step guidance. You may wish to manually follow the steps if you are new to Cloudflare Workers. ## 1\. Create a new Cloudflare Workers project Use [C3 ↗](https://developers.cloudflare.com/learning-paths/workers/get-started/c3-and-wrangler/#c3), the command-line tool for Cloudflare's developer products, to create a new directory and initialize a new Worker project: npm yarn pnpm ``` npm create cloudflare@latest -- express-d1-app ``` ``` yarn create cloudflare express-d1-app ``` ``` pnpm create cloudflare@latest express-d1-app ``` For setup, select the following options: * For _What would you like to start with?_, choose `Hello World example`. * For _Which template would you like to use?_, choose `Worker only`. * For _Which language do you want to use?_, choose `TypeScript`. * For _Do you want to use git for version control?_, choose `Yes`. * For _Do you want to deploy your application?_, choose `No` (we will be making some changes before deploying). Change into your new project directory: ``` cd express-d1-app ``` ## 2\. Install Express and dependencies In this tutorial, you will use [Express.js ↗](https://expressjs.com/), a popular web framework for Node.js. To use Express in a Cloudflare Workers environment, install Express along with the necessary TypeScript types: npm yarn pnpm bun ``` npm i express @types/express ``` ``` yarn add express @types/express ``` ``` pnpm add express @types/express ``` ``` bun add express @types/express ``` Express.js on Cloudflare Workers requires the `nodejs_compat` [compatibility flag](https://developers.cloudflare.com/workers/configuration/compatibility-flags/). This flag enables Node.js APIs and allows Express to run on the Workers runtime. Add the following to your Wrangler configuration file: * [ wrangler.jsonc ](#tab-panel-9783) * [ wrangler.toml ](#tab-panel-9784) JSONC ``` { "compatibility_flags": [ "nodejs_compat" ] } ``` TOML ``` compatibility_flags = [ "nodejs_compat" ] ``` ## 3\. Create a D1 database You will now create a D1 database to store member information. Use the `wrangler d1 create` command to create a new database: ``` npx wrangler d1 create members-db ``` The command will create a new D1 database and ask you the following questions: * **Would you like Wrangler to add it on your behalf?**: Type `Y`. * **What binding name would you like to use?**: Type `DB` and press Enter. * **For local dev, do you want to connect to the remote resource instead of a local resource?**: Type `N`. ``` ⛅️ wrangler 4.44.0 ─────────────────── ✅ Successfully created DB 'members-db' in region WNAM Created your new D1 database. To access your new D1 Database in your Worker, add the following snippet to your configuration file: { "d1_databases": [ { "binding": "members_db", "database_name": "members-db", "database_id": "" } ] } ✔ Would you like Wrangler to add it on your behalf? … yes ✔ What binding name would you like to use? … DB ✔ For local dev, do you want to connect to the remote resource instead of a local resource? … no ``` The binding will be added to your Wrangler configuration file. * [ wrangler.jsonc ](#tab-panel-9785) * [ wrangler.toml ](#tab-panel-9786) JSONC ``` { "d1_databases": [ { "binding": "DB", "database_name": "members-db", "database_id": "" } ] } ``` TOML ``` [[d1_databases]] binding = "DB" database_name = "members-db" database_id = "" ``` ## 4\. Create database schema Create a directory called `schemas` in your project root, and inside it, create a file called `schema.sql`: schemas/schema.sql ``` DROP TABLE IF EXISTS members; CREATE TABLE IF NOT EXISTS members ( id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, email TEXT NOT NULL UNIQUE, joined_date TEXT NOT NULL ); -- Insert sample data INSERT INTO members (name, email, joined_date) VALUES ('Alice Johnson', 'alice@example.com', '2024-01-15'), ('Bob Smith', 'bob@example.com', '2024-02-20'), ('Carol Williams', 'carol@example.com', '2024-03-10'); ``` This schema creates a `members` table with an auto-incrementing ID, name, email, and join date fields. It also inserts three sample members. Execute the schema file against your D1 database: ``` npx wrangler d1 execute members-db --file=./schemas/schema.sql ``` The above command creates the table in your local development database. You will deploy the schema to production later. ## 5\. Initialize Express application Update your `src/index.ts` file to set up Express with TypeScript. Replace the file content with the following: src/index.ts ``` import { env } from "cloudflare:workers"; import { httpServerHandler } from "cloudflare:node"; import express from "express"; const app = express(); // Middleware to parse JSON bodies app.use(express.json()); // Health check endpoint app.get("/", (req, res) => { res.json({ message: "Express.js running on Cloudflare Workers!" }); }); app.listen(3000); export default httpServerHandler({ port: 3000 }); ``` This code initializes Express and creates a basic health check endpoint. The key import `import { env } from "cloudflare:workers"` allows you to access [bindings](https://developers.cloudflare.com/workers/runtime-apis/bindings/) like your D1 database from anywhere in your code. The [httpServerHandler](https://developers.cloudflare.com/workers/runtime-apis/nodejs/http/#httpserverhandler) integrates Express with the Workers runtime, enabling your application to handle HTTP requests on Cloudflare's network. Next, execute the typegen command to generate type definitions for your Worker environment: ``` npm run cf-typegen ``` ## 6\. Implement read operations Add endpoints to retrieve members from the database. Update your `src/index.ts` file by adding the following routes after the health check endpoint: src/index.ts ``` // GET all members app.get('/api/members', async (req, res) => { try { const { results } = await env.DB.prepare('SELECT * FROM members ORDER BY joined_date DESC').all(); res.json({ success: true, members: results }); } catch (error) { res.status(500).json({ success: false, error: 'Failed to fetch members' }); } }); // GET a single member by ID app.get('/api/members/:id', async (req, res) => { try { const { id } = req.params; const { results } = await env.DB.prepare('SELECT * FROM members WHERE id = ?').bind(id).all(); if (results.length === 0) { return res.status(404).json({ success: false, error: 'Member not found' }); } res.json({ success: true, member: results[0] }); } catch (error) { res.status(500).json({ success: false, error: 'Failed to fetch member' }); } }); ``` These routes use the D1 binding (`env.DB`) to prepare SQL statements and execute them. Since you imported `env` from `cloudflare:workers` at the top of the file, it is accessible throughout your application. The `prepare`, `bind`, and `all` methods on the D1 binding allow you to safely query the database. Refer to [D1 Workers Binding API](https://developers.cloudflare.com/d1/worker-api/) for all available methods. ## 7\. Implement create operation Add an endpoint to create new members. Add the following route to your `src/index.ts` file: src/index.ts ``` // POST - Create a new member app.post("/api/members", async (req, res) => { try { const { name, email } = req.body; // Validate input if (!name || !email) { return res.status(400).json({ success: false, error: "Name and email are required", }); } // Basic email validation (simplified for tutorial purposes) // For production, consider using a validation library or more comprehensive checks if (!email.includes("@") || !email.includes(".")) { return res.status(400).json({ success: false, error: "Invalid email format", }); } const joined_date = new Date().toISOString().split("T")[0]; const result = await env.DB.prepare( "INSERT INTO members (name, email, joined_date) VALUES (?, ?, ?)" ) .bind(name, email, joined_date) .run(); if (result.success) { res.status(201).json({ success: true, message: "Member created successfully", id: result.meta.last_row_id, }); } else { res .status(500) .json({ success: false, error: "Failed to create member" }); } } catch (error: any) { // Handle unique constraint violation if (error.message?.includes("UNIQUE constraint failed")) { return res.status(409).json({ success: false, error: "Email already exists", }); } res.status(500).json({ success: false, error: "Failed to create member" }); } }); ``` This endpoint validates the input, checks the email format, and inserts a new member into the database. It also handles duplicate email addresses by checking for unique constraint violations. ## 8\. Implement update operation Add an endpoint to update existing members. Add the following route to your `src/index.ts` file: src/index.ts ``` app.put("/api/members/:id", async (req, res) => { try { const { id } = req.params; const { name, email } = req.body; // Validate input if (!name && !email) { return res.status(400).json({ success: false, error: "At least one field (name or email) is required", }); } // Basic email validation if provided (simplified for tutorial purposes) // For production, consider using a validation library or more comprehensive checks if (email && (!email.includes("@") || !email.includes("."))) { return res.status(400).json({ success: false, error: "Invalid email format", }); } // Build dynamic update query const updates: string[] = []; const values: any[] = []; if (name) { updates.push("name = ?"); values.push(name); } if (email) { updates.push("email = ?"); values.push(email); } values.push(id); const result = await env.DB.prepare( `UPDATE members SET ${updates.join(", ")} WHERE id = ?` ) .bind(...values) .run(); if (result.meta.changes === 0) { return res .status(404) .json({ success: false, error: "Member not found" }); } res.json({ success: true, message: "Member updated successfully" }); } catch (error: any) { if (error.message?.includes("UNIQUE constraint failed")) { return res.status(409).json({ success: false, error: "Email already exists", }); } res.status(500).json({ success: false, error: "Failed to update member" }); } }); ``` This endpoint allows updating either the name, email, or both fields of an existing member. It builds a dynamic SQL query based on the provided fields. ## 9\. Implement delete operation Add an endpoint to delete members. Add the following route to your `src/index.ts` file: src/index.ts ``` // DELETE - Delete a member app.delete("/api/members/:id", async (req, res) => { try { const { id } = req.params; const result = await env.DB.prepare("DELETE FROM members WHERE id = ?") .bind(id) .run(); if (result.meta.changes === 0) { return res .status(404) .json({ success: false, error: "Member not found" }); } res.json({ success: true, message: "Member deleted successfully" }); } catch (error) { res.status(500).json({ success: false, error: "Failed to delete member" }); } }); ``` This endpoint deletes a member by their ID and returns an error if the member does not exist. ## 10\. Test locally Start the development server to test your API locally: ``` npm run dev ``` The development server will start, and you can access your API at `http://localhost:8787`. Open a new terminal window and test the endpoints using `curl`: Get all members ``` curl http://localhost:8787/api/members ``` ``` { "success": true, "members": [ { "id": 1, "name": "Alice Johnson", "email": "alice@example.com", "joined_date": "2024-01-15" }, { "id": 2, "name": "Bob Smith", "email": "bob@example.com", "joined_date": "2024-02-20" }, { "id": 3, "name": "Carol Williams", "email": "carol@example.com", "joined_date": "2024-03-10" } ] } ``` Test creating a new member: Create a member ``` curl -X POST http://localhost:8787/api/members \ -H "Content-Type: application/json" \ -d '{"name": "David Brown", "email": "david@example.com"}' ``` ``` { "success": true, "message": "Member created successfully", "id": 4 } ``` Test getting a single member: Get a member by ID ``` curl http://localhost:8787/api/members/1 ``` Test updating a member: Update a member ``` curl -X PUT http://localhost:8787/api/members/1 \ -H "Content-Type: application/json" \ -d '{"name": "Alice Cooper"}' ``` Test deleting a member: Delete a member ``` curl -X DELETE http://localhost:8787/api/members/4 ``` ## 11\. Deploy to Cloudflare Workers Before deploying to production, execute the schema file against your remote (production) database: ``` npx wrangler d1 execute members-db --remote --file=./schemas/schema.sql ``` Now deploy your application to the Cloudflare network: ``` npm run deploy ``` ``` ⛅️ wrangler 4.44.0 ─────────────────── Total Upload: 1743.64 KiB / gzip: 498.65 KiB Worker Startup Time: 48 ms Your Worker has access to the following bindings: Binding Resource env.DB (members-db) D1 Database Uploaded express-d1-app (2.99 sec) Deployed express-d1-app triggers (5.26 sec) https://.workers.dev Current Version ID: ``` After successful deployment, Wrangler will output your Worker's URL. ## 12\. Test production deployment Test your deployed API using the provided URL. Replace `` with your actual Worker URL: Test production API ``` curl https:///api/members ``` You should see the same member data you created in the production database. Create a new member in production: Create a member in production ``` curl -X POST https:///api/members \ -H "Content-Type: application/json" \ -d '{"name": "Eva Martinez", "email": "eva@example.com"}' ``` Your Express.js application with D1 database is now running on Cloudflare Workers. ## Conclusion In this tutorial, you built a Members Registry API using Express.js and D1 database, then deployed it to Cloudflare Workers. You implemented full CRUD operations (Create, Read, Update, Delete) and learned how to: * Set up an Express.js application for Cloudflare Workers * Create and configure a D1 database with bindings * Implement database operations using D1's prepared statements * Test your API locally and in production ## Next steps * Learn more about [D1 database features](https://developers.cloudflare.com/d1/) * Explore [Workers routing and middleware](https://developers.cloudflare.com/workers/runtime-apis/) * Add authentication to your API using [Workers authentication](https://developers.cloudflare.com/workers/runtime-apis/handlers/) * Implement pagination for large datasets using [D1 query optimization](https://developers.cloudflare.com/d1/worker-api/) ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/workers/","name":"Workers"}},{"@type":"ListItem","position":3,"item":{"@id":"/workers/tutorials/","name":"Tutorials"}},{"@type":"ListItem","position":4,"item":{"@id":"/workers/tutorials/deploy-an-express-app/","name":"Deploy an Express.js application on Cloudflare Workers"}}]} ```