Unexpected 401 Unauthorized scenarios when accessing a secured Node.js REST API with JWT
I'm upgrading from an older version and I'm working with an scenario where my Node.js REST API, secured with JSON Web Tokens (JWT), intermittently returns a 401 Unauthorized behavior when requests are made to a specific endpoint... I'm using Express 4.17.1 and jsonwebtoken 8.5.1. The endpoint is supposed to return user details but sometimes it fails. I've implemented middleware to verify the JWT like this: ```javascript const jwt = require('jsonwebtoken'); function authenticateToken(req, res, next) { const token = req.headers['authorization'] && req.headers['authorization'].split(' ')[1]; if (!token) return res.sendStatus(401); jwt.verify(token, process.env.ACCESS_TOKEN_SECRET, (err, user) => { if (err) return res.sendStatus(403); req.user = user; next(); }); } ``` I attach the token in the Authorization header as follows: ```javascript const response = await fetch('http://localhost:3000/api/users/me', { method: 'GET', headers: { 'Authorization': `Bearer ${token}` } }); ``` However, I've noticed that under heavy load, or if multiple requests are sent in quick succession, I start receiving the 401 behavior for some requests. I've tried logging the token being sent and verified it on the server-side, which appears correct. I'm also checking the expiration time of the token, but all tokens are still valid at the time of the request. Could this be an scenario with JWT validation timing out under load, or is there a possibility that the token gets invalidated prematurely? Any insights or suggestions on how to debug this more effectively would be greatly appreciated! Thanks in advance! This is part of a larger mobile app I'm building. Thanks for any help you can provide! Any advice would be much appreciated.