Node.js JWT Auth with TypeScript

Implement JWT authentication in a Node.js Express server with TypeScript, including token signing, verification middleware, refresh token rotation, and.

Typescript Node Auth Jwt Updated: 2026-01-15

Code

snippet

import jwt from 'jsonwebtoken';
import { Request, Response, NextFunction } from 'express';

declare module 'express' {
  interface Request { userId?: string;}
}

export function authMiddleware(req: Request, res: Response, next: NextFunction) {
  const token = req.headers.authorization?.split(' ')[1];
  if (!token) return res.status(401).json({ error: 'No token' });
  try {
    const payload = jwt.verify(token, process.env.JWT_SECRET!) as { sub: string };
    req.userId = payload.sub;
    next();
  } catch {
    res.status(401).json({ error: 'Invalid token' });
  }
}