It Does Not Have to Ship: In Praise of Single-Purpose Apps Built for Yourself with AI

Since natural-language programming with AI agents became possible, what I have enjoyed most is building single-purpose apps for myself. There is no plan to release them, so the code does not have to be beautiful. It just has to make my own work easier. That lightness is the best part of programming in the age of AI, so here are some examples.

Example 1: a Mac app for editing captions (my first Swift)

Editing captions on video is a step where manual work remains even after optimizing with AI. To shorten it, I built a dedicated Mac app. The language was Swift — my first time with it. Not knowing anything is fine as long as you keep giving Codex instructions in your own language.

The trick is to settle the specification with the AI before starting to build. Issuing instructions a little at a time took about two weeks, but the result fits my work better than the existing video editing software does.

Example 2: a video format converter (thirty minutes)

Converting recordings from game streaming software (.mkv) into the general-purpose mp4 format was quietly annoying enough that I had started avoiding recording at all. So I built a small tool that converts a file when you drag and drop it onto the icon. About thirty minutes including deciding what it should do.

Having got the hang of it, I built a tool to extract just the audio from an mp4 in about five minutes, so that files going to a transcription AI (Whisper) would be lighter.

Example 3: a simple editor for game footage (thirty minutes again)

I also built a video tool with only three features: adding a blur, exporting a selected range, and adding background music. A deliberately limited app for work that does not justify launching professional editing software. Around thirty minutes as well.

Building for yourself means you can be relaxed about it

If you are the only user, messy code and rough edges do no real harm (distributing it is another matter). Only two things matter.

• Narrow it to the single function you find inconvenient — being greedy raises the difficulty sharply
• Settle the specification with the AI before building, to avoid wandering partway through

This style of development — describing roughly what you want and having it built — is known as vibe coding, and it is open to non-engineers. Think of one small daily annoyance and build something for it. The feeling of thirty minutes making every day slightly better is habit-forming.

This article is adapted for AI Jiten from testing notes originally published on the author’s blog, Delaymania.