Architecture-first vs problem-first: what five months of over-engineering looks like

Why build something? And what if nobody ends up using it? There are good answers to the first one. You build because you need a thing that doesn't exist yet. You build to see if you can, the technical challenge, the "is this even possible?" You build to impress someone, or just because you think it'll make people's day a little less annoying. All of those are real reasons, and at different points, I told myself most of them. Then, a few days ago, late in the day, at the end of a coding session, five months into the project, I asked myself those two questions back-to-back. And for the first time, I couldn't answer the second one. Zeri worked. Every feature did what it was supposed to do. Both processes handshake cleanly, a variable set in one context showing up in another a second later, the TUI rendering exactly as I'd pictured it. And I sat there and couldn't come up with one honest sentence explaining why anyone would actually download it. That gap, between something built well and something that has a reason to exist, turned out to be the most useful thing this whole project taught me. So I'm shipping it anyway, and I'll tell you why. What I built Zeri is a TUI multi-language REPL. You launch it, pick a language, Python , JavaScript (with Bun ), Ruby , or LuaJIT , and you get an interactive session in your terminal. You can switch languages mid-session, share variables across them, save and reload your work, manage snippets, and talk to a local LLM through a command running on Ollama . The feature list isn't the interesting part, though. The interesting part is what's underneath. Two processes, one app Zeri is split into two processes: a headless engine written in C++23 and a TUI frontend built in Go using Bubble Tea and Lip Gloss . The engine does all the evaluation, state, and runtime coordination. The frontend does rendering, input, and everything the user actually sees and touches. They talk to each other over a custom binary IPC protocol that I built from sc