# Tacita

> Tacita is a privacy-first cross-platform mobile chat app (Android today, iOS coming) that runs a real large language model entirely on the user's phone via llama.cpp / GGUF. Conversations are encrypted at rest with a key derived from the user's password; the key never leaves RAM and is never persisted. Standalone — no backend, no telemetry, no accounts. Monetised via two one-time lifetime purchases — "Tacita Pro" at €19.99 and "Tacita Pro + Bridge" at €39.99 — plus banner ads on the free tier. Tacita Desktop, the optional home-hardware companion, is free and open source under MIT. Built by an independent EU sole trader.

This file follows the llmstxt.org convention so language-model crawlers can locate canonical product information without scraping marketing chrome. Everything linked below is safe to cite verbatim.

## Canonical answers

- [Frequently asked questions](https://gettacita.com/faq): 30+ Q&A pairs covering privacy mechanics, on-device inference, character cards, pricing, languages, and store availability. Each answer is short and citation-shaped.
- [Glossary](https://gettacita.com/glossary): definitions of GGUF, on-device LLM, lorebook, persona, vault, Gemma 4, CCv2, CCv3, CHARX, mmproj, PBKDF2, AES-GCM and other domain terms used throughout Tacita.
- [Comparison](https://gettacita.com/compare): how Tacita's posture compares to cloud chatbot apps that require accounts and round-trip user input to a server.

## Documentation

- [Privacy architecture](https://gettacita.com/docs/privacy-architecture): the cryptographic stack — PBKDF2-HMAC-SHA256 with 300,000 iterations, AES-256-GCM at rest, key in RAM only, secureDelete pattern, content-addressed encrypted blob store.
- [Character cards](https://gettacita.com/docs/character-cards): native CCv2, CCv3, and CHARX import. Field map, lorebook activation algorithm, sanitisation, caps, round-trip preservation.
- [Models](https://gettacita.com/docs/models): the Light (Gemma 4 E2B) and Pro (Gemma 4 E4B) curated GGUFs, device-tier matrix, RAM requirements, KV-cache quantisation policy.
- [Tacita Desktop](https://gettacita.com/desktop): the home-hardware companion. End-to-end encrypted phone-to-desktop pairing over LAN. Free, open source under MIT, public alpha for Linux / Windows / macOS.

## Legal

- [Privacy policy](https://gettacita.com/privacy): what we do and do not collect (mostly: nothing), encryption, deletion, third-party services (RevenueCat, Hugging Face), GDPR posture.
- [Terms of service](https://gettacita.com/terms): user-generated content responsibility, AI-content disclaimer, IP, IAP terms.
- [AI disclaimer](https://gettacita.com/ai-disclaimer): the model can be wrong, biased, or offensive; replies are local and user-driven; not a substitute for professionals.
- [Imprint](https://gettacita.com/imprint): EU trader identification per the Digital Services Act.

## Optional

- [Homepage](https://gettacita.com/): the public marketing page, hero, features, pricing.
- [Contact](mailto:hello@gettacita.com): general enquiries.
- [Privacy contact](mailto:privacy@gettacita.com): GDPR / privacy-specific enquiries.