I built my husband a vim trainer with a Gemma coach that runs in the browser

Description and use

A browser-based Vim trainer, hjkl, uses short real‑vim drills and a Gemma AI coach running on WebGPU. The target user, the author’s husband, continued practicing and showed increased motivation.

Problem

My husband struggled to learn Vim because of too many commands to memorize and slow, awkward experience compared to his usual tools.

Outcome

The husband engaged with the app, completed drills, and continued practicing without external prompting, indicating increased motivation and learning retention.

Workflow

• 1. Design lessons with a small set of commands and a cheat sheet. 2. Create drills that use a real CodeMirror 6 vim plugin. 3. Implement a review list for over‑par solutions. 4. Add a full Vim reference searchable by key or VS Code shortcut. 5. Integrate Gemma 4 E2B as an optional AI coach via Transformers.js on WebGPU. 6. Generate new drills with Gemma and validate them through real‑vim execution. 7. Deploy as a static site on Cloudflare Workers.

Evidence

My husband has wanted to learn vim for a long time. He's tried a bunch of times, and it always ends the same way: he gives up.

Source

Each drill gives you a small buffer, a goal, and a keystroke "par" to beat. You solve it in a real vim editor, not a simulation.

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The AI coach is optional and off by default. When you turn it on, it downloads Gemma 4 E2B once and runs it in a Web Worker on WebGPU with Transformers.js.

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On my machine, Gemma 4 E2B writes about 6 to 7 tokens a second, so a one-sentence explanation takes a few seconds.

Source

When I handed it over to him, he actually sat there and worked through it for a while, which felt like a pretty good sign considering every previous attempt at learning vim had ended with him giving up.

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