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Lukasz
Lukasz

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I built a content tool where the AI runs 100% in the browser — no servers, no API keys

#ai #javascript #showdev #webdev

Most "AI content" tools send everything you write to a server. I didn't want that — so I built 24U to run the model entirely in the browser.

The idea

Paste one article, note, or voice memo → get 11 platform-native posts (LinkedIn, Instagram, TikTok, X, Reddit, YouTube, Threads, Pinterest, Telegram, WhatsApp, Facebook). Each written for that platform's style, not copy-paste.

The twist: nothing you write ever leaves your device.

How it runs locally

  • WebLLM + WebGPU load a quantized LLM into the browser. After a one-time ~2GB download it runs offline.
  • No backend inference, no API keys, no per-token cost — the "server" is the user's own GPU.
  • COOP/COEP headers enable SharedArrayBuffer (required for the WASM/WebGPU runtime).
  • ONNX/native deps are kept out of the server bundle so the Next.js function stays tiny.

Tradeoffs (honest)

  • Needs a WebGPU browser — Chrome/Edge today, Safari/Firefox are WIP.
  • That one-time 2GB download is the price of full privacy + offline use.
  • A small in-browser model isn't GPT-4 — but for "rewrite this for platform X" it's more than enough, and it never sees a server.

Why one-time pricing

No server compute to pay for → no subscription. You own it once.

Building 24U solo and in public — privacy-first AI that runs 100% in your browser (competitive analysis, SWOT & content from your data, nothing uploaded). I'm all-in and running lean. If it resonates, support means the world — backers get a free lifetime license 🙏 ko-fi.com/lukaszdev

Curious what the dev crowd thinks of in-browser inference as a privacy pattern — would you trust "runs locally" over "we promise we don't read your data"?

Try it: https://24-u.vercel.app/landing

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