https://www.codikko.com/blog Codikko teaches software development through interactive, animated lessons instead of videos: watch the system move, and drive every step yourself. https://www.codikko.com/blog/401-vs-403-the-difference https://www.codikko.com/blog/401-vs-403-the-difference Thu, 03 Sep 2026 00:00:00 GMT 401 means the server doesn't know who you are; 403 means it does, and the answer is no. Watch one request hit both gates. https://www.codikko.com/blog/express-middleware-explained-step-by-step https://www.codikko.com/blog/express-middleware-explained-step-by-step Thu, 03 Sep 2026 00:00:00 GMT Middleware is a line of functions every request walks before your handler. Watch three stations stamp one request in order, then a missing token stop it early. https://www.codikko.com/blog/how-the-node-event-loop-works https://www.codikko.com/blog/how-the-node-event-loop-works Thu, 03 Sep 2026 00:00:00 GMT Node runs on one thread yet never blocks. Watch one async callback wait in the queue and get pushed onto the call stack to see how. https://www.codikko.com/blog/http-status-codes-the-eight-you-need https://www.codikko.com/blog/http-status-codes-the-eight-you-need Thu, 03 Sep 2026 00:00:00 GMT You don't need dozens of status codes. Watch one request get 200, 301, 401, 404 and 500, learn the first digit rule, and keep the eight that cover real traffic. https://www.codikko.com/blog/jwt-vs-session-authentication https://www.codikko.com/blog/jwt-vs-session-authentication Thu, 03 Sep 2026 00:00:00 GMT Sessions can be revoked; JWTs verify themselves. Watch one request take each path, then pick the trade-off that fits what you are building. https://www.codikko.com/blog/what-port-3000-already-in-use-means https://www.codikko.com/blog/what-port-3000-already-in-use-means Thu, 03 Sep 2026 00:00:00 GMT EADDRINUSE means a process is still listening on that port. Watch one machine give door 3000 to the first process, refuse the second, then fix it both ways.