I built a ManyChat clone with real-time automation flows using Flutter + Elysia.js — here's what I learned
Hey everyone 👋
I'm Sumit, a solo dev/agency founder. I've been building a ManyChat-style chatbot automation platform and wanted to share what I've learned so far — the good, the bad, and the painful.
What I built: A multi-channel chatbot builder with visual flow editor, trigger-based automation, and AI integrations — similar to ManyChat but with a custom backend.
The stack:
- Frontend: Next.js + React
- Mobile: Flutter (iOS + Android)
- Backend: Started with Express.js → migrated to Elysia.js on Bun
- Real-time: WebSockets + SSE for live flow updates
- AI: OpenAI API for smart reply suggestions
Why we ditched Express mid-build: Scaling issues hit us earlier than expected. Express started showing its limits under concurrent flow executions. Elysia.js on Bun was 3x faster in our benchmarks and the DX is honestly really nice. If you're building anything real-time heavy in 2026, seriously consider it.
Biggest challenge: SSE streaming. "Fake streaming" (buffering the whole response then sending it) breaks under Cloudflare's 100s timeout for long AI tasks. Real chunked streaming was the fix — painful to get right, worth it.
What's working:
- Visual drag-drop flow builder
- Multi-step onboarding module
- AI-powered reply generation mid-conversation
Still building this at 2xstudio.in
Happy to answer any questions about the stack, SSE streaming, or the migration from Express → Elysia.
What are you all building this weekend? 🚀