I’ve been a software engineer for 5+ years (senior now), coding for like 8 years… and somehow I’d never built a login page before. So in this video I challenge myself to build the “best” login screen for my German language app, Lex. For me, “best” means a balance of cost (ideally free), dev time (I gave myself about an hour), and the biggest chunk: user experience. I used ChatGPT to sanity-check the UI/UX and the fastest implementation path, then decided to go with Firebase Authentication because it’s the easiest way to ship something secure quickly. I sketch a simple UI: welcome text, email + password, a submit button, and Google OAuth at the bottom—because I personally love having both options. I also want one combined flow: if the user exists, log them in; if not, sign them up—no separate login and signup pages. The “plot twist” is my Lex project setup (separate frontend/backend) wasn’t playing nicely with the tools, so I converted it into a Next.js project first. After that, I used shadcn/ui components for a clean look, wired up Firebase, tested email/password, then added Google OAuth. Biggest takeaway: the auth setup was surprisingly fast; the Next.js conversion and a couple documentation detours took the most time. Next up for Lex: protected routes and actual user accounts/progress.