# AI companion apps > The stack behind AI companion and character apps: RP+ chat that stays in persona, vision, Voice Turbo replies, Scribe One for call mode, Image One for selfies, a written policy instead of a filter. Flat credits, OpenAI-shaped. A companion app is four modalities pretending to be one person. eroq ships them behind one key: RP+ or RP mini for the conversation (scene or messaging register), vision so the user can send a picture, Voice Turbo to speak every reply, Scribe One for call mode, Image One for the selfie — governed by a written acceptable-use policy that you can pass through to your users. ## The request pattern - Chat: POST /v1/chat/completions with the persona in `context`, messaging mode for DM-style products, SSE streaming. - Voice: POST /v1/audio/speech with the character's voice (`char:`) on Voice Turbo — 2 credits per 100 characters. - Call mode: Scribe One transcribes the user (5 credits), RP+ answers, Turbo speaks. - Pictures: Image One with the Character's references — the same face, 10 credits. ## Why a policy wall beats a filter The model stays in character on mature turns within policy; the hard limits (no minors, no real people, nothing illegal) return an explicit content_blocked error you can handle — never a lecture mid-scene, never a charge. Deterministic enough to build moderation on. ## FAQ ### What does a companion conversation cost? A reply on RP mini is 1 credit, on RP+ 3; a spoken reply of 200 characters adds 4 credits on Voice Turbo. A hundred spoken turns on mini-plus-Turbo is about 500 credits. ### Is it OpenAI-compatible? Yes — chat completions follow the OpenAI shape; existing code ports by changing the base URL and model id. ### Can my users send pictures? Yes — image parts in a user turn, 2 credits each; the character reacts to what it sees. ## Related - https://eroq.ai/models/eroq-rp-plus — RP+ - https://eroq.ai/models/eroq-voice-turbo — Voice Turbo - https://eroq.ai/blog/how-to-build-an-ai-girlfriend-app — Build guide - https://eroq.ai/nsfw-ai-api — NSFW AI API --- This page as HTML: https://eroq.ai/use-cases/ai-companion-apps · Studio: https://eroq.ai/studio · Docs: https://eroq.ai/docs · Machine index: https://eroq.ai/llms.txt