Why we built Flack

Slack is bloated. We built something better — a team chat app under 10MB with instant messaging, offline support, and AI built in from day one.

productphilosophy

The problem is obvious

Slack’s desktop app is over 500MB. It uses a gigabyte of RAM to show text messages. It ships an entire Chromium browser just to render a chat window.

Every team communication tool has followed the same playbook: wrap a web app in Electron, call it “native,” and ship it. The result? Slow startup, battery drain, and the constant background hum of a browser you didn’t ask for.

We got tired of it.

What we built instead

Flack is team communication rebuilt from the ground up with a different set of priorities:

Under 10MB. Our desktop app uses Tauri, which leverages your OS’s native webview. No bundled Chromium. No 500MB downloads. Just your team’s messages.

0ms message latency. When you hit send, your message appears instantly. We use optimistic UI — your message renders locally while the server catches up in the background. No spinner. No “sending…” state.

Offline first. Messages queue in IndexedDB when you lose connection. When you’re back online, they sync automatically. Your work doesn’t stop because your WiFi hiccuped.

AI from day one. @flack is an AI teammate that lives in your channels — not a chatbot in a sidebar. It reads your team’s knowledge base, creates and manages todos, and executes multi-step tasks. AI isn’t a feature we bolted on. It’s how Flack was designed to work.

The technical choices

We didn’t just pick lighter tools — we picked tools that make the product fundamentally different:

  • Svelte 5 for the frontend. Fine-grained reactivity with minimal runtime overhead.
  • Convex for the backend. Real-time WebSocket push means no polling, no stale data.
  • Tauri for the desktop app. Native OS webview, not Electron.
  • IndexedDB for offline queuing. Messages survive page refreshes and network drops.

Every architectural decision serves the same goal: your messages should feel instant, your app should feel native, and your AI teammate should actually understand what’s going on.

What’s next

We’re opening up early access soon. If you’re tired of waiting for your chat app to load, join the waitlist.

Want to try Flack?