This is a submission for the DEV April Fools Challenge

NyanZip: The Delightfully Useless Cat-Language Compression App

What I Built

I built NyanZip, a browser-based joke app that takes normal text and turns it into exaggerated cat language.

It has two modes:

• A playful "compress" mode that expands text into a noisy stream of meow and MEOW!!
• An "ultra" mode that uses real compression under the hood, but still wraps everything in cat-themed nonsense

It also includes optional Gemini-powered cat commentary, because every compression tool deserves a tiny, judgmental reviewer in a bow tie.

The result is intentionally impractical, a little chaotic, and exactly the kind of project that feels right for April Fools.

Demo

Live demo: https://moe-charm.github.io/dev_challenges/20260402april/

Repository: https://github.com/moe-charm/dev_challenges

Code

The code is all in the repository above. The main pieces are:

• App shell and UI: 20260402april/index.html
• Main interaction logic: 20260402april/app.js
• Cat-text encoder and decoder: 20260402april/js/engine.js
• Ultra compression pipeline: 20260402april/js/rans.js
• Optional AI cat review feature: 20260402april/js/chat.js
• Localization strings: 20260402april/js/i18n.js

How I Built It

I built NyanZip with plain HTML, CSS, and JavaScript.

A few things made it fun to put together:

• TextEncoder and TextDecoder for converting text to bytes and back
• CompressionStream and DecompressionStream for the ultra mode
• A simple bilingual UI for Japanese and English
• Optional Gemini integration for the cat review comments

I also published it with GitHub Pages so the joke works directly in the browser, with no setup required.

Prize Category

I’d submit this for Community Favorite.

It is intentionally silly, easy to try, and built to make people smile first and ask questions later. The optional Google AI feature adds a fun extra layer, but the core joke stands on its own.