Download
Buy the ready-to-run app on Steam for $9.99, or build the open-source code yourself for free. Either way it runs entirely on your computer.
Two ways to get it — both run 100% on your computer
Conversation Simulator is free and open source. The engine is Apache-2.0 and the four official scenario packs are CC BY 4.0, so you can always clone the repository , build it, and run it at no cost — see the developer install guide .
The $9.99 Steam edition is that same software, packaged: code-signed and notarized, auto-updating, Steam Deck–verified, with Steam Cloud settings sync and achievements. You are not paying to unlock the product — it is open in the source. You are paying for a build you don’t have to assemble yourself, and to fund continued development. The local-first guarantee is identical either way: nothing is transmitted to any server during play.
Premium scenario packs
Beyond the four free official packs, first-party premium scenario-pack expansions — advanced professional skills, extended language courses, and themed conversation bundles — are available as paid downloadable content on Steam. They are optional add-ons on top of the free core; nothing that ships free is ever moved behind the paywall.
What to expect on first launch
No model ships in the box — you choose what runs on your machine. On first launch the app walks you through downloading a starter model (Qwen3 4B Instruct, ~2.5 GB, Apache-2.0), with the license and size shown before anything is fetched. One model download is the only time the app needs the internet. After that, everything works offline.
Recommended hardware: any 64-bit machine with 8 GB RAM runs the starter model; 6 GB+ of VRAM unlocks the larger, sharper models. Full details in the install guide and local models guide .
For developers
The whole platform is open source (Apache-2.0) on GitHub — see the developer install guide to run it from source and the contributing guide to get involved. Contributions to the open core are always welcome; the premium expansion packs are developed separately and sold to sustain the project.
Having trouble?
The troubleshooting guide covers the common failure modes, and GitHub issues are open to everyone. Beta builds include a one-click, fully-redacted diagnostic report — nothing is ever uploaded automatically.