Prompto

Prompto is the open-source web app that makes interacting with large language models feel simple and lightweight. If you've wanted a clean, no-fuss interface to chat with your LLM of choice, fine-tune its responses, and save the prompts that work best — without installing anything — Prompto is exactly that.

It runs entirely in your browser as a Progressive Web Application (PWA) and communicates directly with your chosen LLM provider through LangChain.js integrations. No backend, no setup, no lock-in. Just open it, connect your API, and start exploring what your LLM can do — completely in your control.