Chatmosphere

Chatmosphere is a free, browser-based AI platform that lets users build and chat with custom “characters” instead of a single generic assistant. After signing in with Google, creators can spawn any persona—real or imagined—by simply describing it in plain language. The engine then writes a back-story, chooses an appropriate face from an open-source avatar library, and spins up a dedicated GPT instance that stays in character across sessions.

Key features emphasized on the landing page include:
1. Zero-code character creation – no scripting or JSON forms; a short prompt is enough.
2. Persistent memory – every character keeps its own conversation history, so context survives refresh or logout.
3. Group rooms – multiple characters can be placed in the same thread and will talk to one another autonomously while the user watches or jumps in.
4. Knowledge injection – upload PDF, TXT or MD files up to 10 MB; the bot references that private knowledge when answering, making it useful for internal wikis, rulebooks or study notes.
5. Voice reply toggle – one click switches replies to open-source TTS, letting the conversation be heard instead of read.
6. Export & share – any character can be exported as a JSON prompt-pack and shared via URL; recipients can clone it to their own dashboard with one click.
7. Commercial licence – the site explicitly states that output from user-created bots can be used commercially, including for client work or monetised content.
8. No install – the whole workflow runs in browser tabs on desktop or mobile; there is no downloadable app or plug-in.
9. Open-source ethos – the project links its GitHub repo, invites pull requests, and says all avatars and voices are drawn from permissive licences.

The front page positions Chatmosphere as “the fastest way to spin up a specialist AI that actually remembers you,” contrasting it with generic chatbots that reset every session. Use cases illustrated on the site include: a D&D dungeon master who recalls last week’s quest, a customer-support bot trained on a private returns policy, and a “writers’ room” of three personas that brainstorm plot ideas together.