This content originally appeared on DEV Community and was authored by William Onyejiaka
Express is a fast, minimalist web framework for Node.js, and combining it with TypeScript brings type safety and better tooling to your server-side development. In this blog, I'll walk you through setting up a basic Express server with TypeScript from scratch. By the end, you'll have a working server with proper configuration, ready for building robust APIs.
Prerequisites
Before we dive in, ensure you have the following installed:
Node.js (v16 or higher recommended)
npm
A code editor like VS Code or any one that you feel comfortable with
Basic knowledge of TypeScript and Express
Step 1: Initialize Your Project
mkdir express-ts-server
cd express-ts-server
npm init -y
This creates a folder named express-ts-server and a package.json file with default settings.
Step 2: Install Dependencies
Install the necessary dependencies for Express and TypeScript:
npm install express
npm install --save-dev typescript @types/node @types/express ts-node nodemon
Explanation of Dependencies
express: The Express framework for building the server.typescript: The TypeScript compiler.@types/nodeand@types/express: Type definitions for Node.js and Express to ensure TypeScript compatibility.ts-node: Allows running TypeScript files directly without pre-compiling.nodemon: Automatically restarts the server during development when files change.
Step 3: Set Up TypeScript Configuration
Create a tsconfig.json file to configure TypeScript. Run the following command to generate a basic configuration:
npx tsc --init
Modify the tsconfig.json file to include the following settings:
{
"compilerOptions": {
"module": "commonjs",
"rootDir": "./src",
"outDir": "./dist",
"moduleResolution": "node10",
"strict": true,
"esModuleInterop": true,
"skipLibCheck": true,
"forceConsistentCasingInFileNames": true
},
}
Key Settings
target: Specifies the ECMAScript version (ES2020 is modern and widely supported).module: Uses CommonJS for Node.js compatibility.outDir: Outputs compiled JavaScript to the dist folder.rootDir: Keeps source files in the src folder. It can be any folder of your choosing.strict: Enables strict type-checking for better code quality.
Step 4: Set Up Project Structure
Create a src directory to hold your TypeScript files:
mkdir src
touch src/server.ts
Your project structure should look like this:
express-ts-server/
├── node_modules/
├── src/
│ └── server.ts
├── package.json
├── tsconfig.json
If its not, go back to the previous steps.
Step 5: Create the Express Server
Open src/server.ts and add the following code to set up a basic Express server:
import express, { Application, Request, Response } from "express";
const app: Application = express();
const port = 3000; // The port your express server will be running on.
// Enable URL-encoded form data parsing
app.use(express.urlencoded({ extended: true }));
// Middleware to parse JSON bodies
app.use(express.json());
// Basic route
app.get('/', (req: Request, res: Response) => {
res.send('Hello, TypeScript + Express!');
});
// Start the server
app.listen(port, () => {
console.log(`Server is running on http://localhost:${port}`);
});
Explanation
We import
expressand theApplication,RequestandResponsetypes from Express.The server listens on port 3000.
A simple GET route at
/responds with a greeting.express.urlencoded({ extended: true })middleware that parses incoming requests with URL-encoded payloadsexpress.json()middleware that parses incoming JSON requests.
Step 6: Configure Scripts in package.json
Update the scripts section in package.json to simplify development and building:
"scripts": {
"start": "node dist/server.js",
"build": "tsc -p .",
"dev": "nodemon src/server.ts"
}
Script Details
start: Runs the compiled JavaScript code.build: Compiles TypeScript to JavaScript in the dist folder,set in yourtsconfig.json.dev: Uses nodemon to run the server and auto-restart on changes.
Step 7: Test the Server
Run the development server:
npm run dev
You should see:
Server is running on http://localhost:3000
Open your browser or use a tool like Postman to visit http://localhost:3000. You should see:
Hello, TypeScript + Express!
Step 8: Build for Production
To compile your TypeScript code to JavaScript for production:
npm run build
This generates a dist folder with compiled JavaScript. Run the production server:
npm start
Conclusion
You now have a fully functional Express server with TypeScript! This setup provides a solid foundation for building scalable APIs with type safety. From here, you can add more routes, connect to a database, or deploy to a platform like Railway or Render.
The full code is here.
This content originally appeared on DEV Community and was authored by William Onyejiaka
William Onyejiaka | Sciencx (2025-10-03T00:58:54+00:00) Setting Up an Express TypeScript Server: A Step-by-Step Guide. Retrieved from https://www.scien.cx/2025/10/03/setting-up-an-express-typescript-server-a-step-by-step-guide/
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