Chat with every AI model at once.
Duplex is a free, browser-only frontend that connects every AI endpoint you own — local or cloud — and streams all their responses side by side. No login. No server. No data leaving your device.
What is Duplex?
Duplex is a universal AI frontend that lives entirely in your browser. Connect your local Ollama server, your OpenAI key, your Anthropic key — as many sources as you want.
Every response streams back in its own panel, side by side. Compare tone, accuracy, speed, and reasoning across models in real time. No backend, no account, no data leaving your device.
Browser-native
Runs entirely in your browser. No server, no backend.
Zero setup
Add your keys or point to your local server. Go.
Privacy first
Your keys and prompts never leave your device.
Open source
MIT licensed. Audit the code yourself.
Everything you need. Nothing you don't.
Simultaneous streaming
One prompt, all endpoints, all at once. Every response streams token by token in its own panel — no waiting for one to finish before the next starts.
8 providers built in
OpenAI, Anthropic, Groq, Gemini, xAI Grok, Perplexity, OpenRouter, and any local OpenAI-compatible server. Add keys, toggle on, go.
Local model support
Point Duplex at your Ollama, LM Studio, or llama.cpp server. Configure host and port. Run completely offline if you want.
Full conversation history
Every conversation is persisted in localStorage. Titles auto-generate from your first message. Switch between chats instantly.
Zero server footprint
Duplex is a static site. No analytics, no telemetry, no backend. Your prompts and keys exist only between your browser and your chosen AI providers.
Open source, MIT
Fork it, self-host it, modify it. The entire codebase is public. Audit the key storage logic yourself — it takes 30 seconds.
Up and running in four steps.
Add your endpoints
OpenAI, Anthropic, Groq, Gemini, xAI, Perplexity, OpenRouter, or local Ollama.
Toggle them on
Activate the endpoints you want to compare.
Send a prompt
Type your message and hit enter.
Compare in real time
Watch every model respond simultaneously, side by side.
Works with every major provider.
sk-...sk-ant-...gsk_...AIza...xai-...pplx-...sk-or-...Your data stays exactly where you put it.
Duplex is a static site. No backend. No database. No analytics. No telemetry. Your API keys are stored only in your browser, obfuscated. Your prompts never leave your device.
Zero backend
Duplex is a static site. No server to compromise.
Obfuscated keys
Your API keys are encrypted in localStorage.
No tracking
Zero analytics, zero telemetry, zero tracking.
Open source
Audit the code yourself. MIT licensed.
Quick pre-launch checklist.
A modern browser (Chrome, Firefox, Safari, Edge) — no install required
At least one API key OR a running local model server (Ollama, LM Studio)
If using Ollama: CORS enabled (one command — see the docs)
Know which model you want to use — or use the defaults
Internet connection for cloud providers; offline works for local-only