Free
$0
- 30 trial messages, then 50 / month
- 1 AI provider
- Bring your own API key
- On-device chats & Keychain
- Streaming Markdown, LaTeX & code
- Themes & basic parameters
- Built-in prompt templates
Start a Conversation
Choose a template, or send a message to start from scratch.
Tap a preset to load model, prompt, tools & memory
The right plan depends on how long I'll stay in the home. I'll pull today's rates from Freddie Mac, then run the amortization on a $500k loan to compare monthly payment and total interest for a 30-year fixed, 15-year fixed, and 5/1 ARM.
{ "query": "current US mortgage rates August 2026", "max_results": 5 }| Plan | Rate | Payment | Interest |
|---|---|---|---|
| 30-yr fixed | 6.69% | $3,223 | $660k |
| 15-yr fixed | 6.01% | $4,222 | $260k |
| 5/1 ARM | 6.51% | $3,163 | $639k |
Monthly payment on a $500k loan:
Amortization in Python:
Chat Presets · Live streaming · LaTeX · Tables · Code
Chat Preset
Stop re-entering the same settings for every task. Chat Presets are reusable prompt templates — model, system prompt, parameters, tools, and memory in one tap.
MCP Tools
MCP servers give the model real capabilities mid-answer.
Demo: add an MCP server (name, URL, transport, bearer token) over Streamable HTTP, validate it, fetch its tools, then watch the assistant search with web_search_exa and fetch the top result with web_fetch_exa while batch_search stays disabled.
Server Details
Authentication
Tools
Memory
Facts worth keeping carry into your next chat, and never leave your device.
3 memories · stays on this device
Parameters
Every knob your provider exposes, no config files.
Appearance
Theme, accent, and text size — app-wide.
Background Tasks
On iOS 26 a reply or a tool run continues after you switch away, with live progress on the Lock Screen and in the Dynamic Island.
Demo: a Lock Screen activity shows a background answer at 62 percent with a Cancel button, above the completion notification that opens the finished conversation.
BayesChat
Running tools…
“Summarize this 40-page filing and flag the risks”
Completion alerts are opt-in, under Settings · Notifications
Pricing
$0
Lifetime
$14.99
Compare
An honest look at the alternatives — each is good at what it does. Here's where the differences are.
| Feature | BayesChat | Chatbox AI | OpenCat | Geeps |
|---|---|---|---|---|
| Reusable Chat Preset | BayesChatYes — save model, prompt, parameters, tools & memory; switch in one tap | Chatbox AINo | OpenCatNo | GeepsPartial — prompt library only |
| Prompt variables | BayesChatYes — date, time & model variables with cache-friendly hints | Chatbox AINo | OpenCatNo | GeepsNo |
| Auto Summarize Title | BayesChatYes — every chat named automatically, with live animation | Chatbox AINo | OpenCatNo | GeepsNo |
| Theme presets | BayesChatYes — Sepia, Solarized, Nord, Rosé Pine, Gruvbox & more | Chatbox AINo | OpenCatNo | GeepsYes — custom accent, background & text |
| Styled export & share | BayesChatYes — PDF, HTML & Markdown with math, code highlighting & theme; batch ZIP | Chatbox AINo | OpenCatPartial — raw text only | GeepsPartial — Markdown only |
| Backup & restore | BayesChatYes — one file backs up everything | Chatbox AINo | OpenCatPartial — iCloud sync only | GeepsPartial — iCloud sync only |
| Usage stats | BayesChatYes — tokens in/out, tok/s & duration per reply | Chatbox AIPartial — some stats | OpenCatNo | GeepsNo |
| Live rendering | BayesChatYes — streaming with LaTeX, tables & syntax-highlighted code | Chatbox AIYes — streaming Markdown | OpenCatPartial — math & tables incomplete | GeepsPartial — no math |
| MCP tools | BayesChatYes — any MCP server per chat with visible tool calls (Pro) | Chatbox AIPartial — hosted Pro/Pro+ plans only | OpenCatYes | GeepsNo — built-in web only |
| Fine-tuned parameters | BayesChatYes — temperature, penalties, stop sequences; saveable into presets | Chatbox AIPartial — small subset | OpenCatPartial — small subset | GeepsYes — per provider & chat |
| Native SwiftUI | BayesChatYes — built for iPhone & iPad | Chatbox AIPartial — cross-platform UI | OpenCatYes | GeepsYes |
| Desktop or web version | BayesChatPartial — Mac version coming soon | Chatbox AIYes — Windows, macOS, Linux & web | OpenCatYes — Mac + iPad | GeepsYes — Mac + iPad |
| Memory | BayesChatYes — facts saved from chats, kept on device; edit or delete any memory | Chatbox AIYes — since 1.23 (Aug 2026); toggle, review & delete in Settings | OpenCatNo | GeepsNo |
| On-device storage | BayesChatYes — Keychain keys, SwiftData chats, no account | Chatbox AIYes — local by default | OpenCatYes — iCloud optional | GeepsYes — iCloud optional |
| One-time purchase | BayesChatYes — Pro $14.99 once, lifetime, no subscription | Chatbox AINo — hosted plans from $3.99/mo | OpenCatNo — subscription for premium features | GeepsYes — $14.99 once + API use |
| Works without your own API key | BayesChatNo — bring your own API key | Chatbox AIYes — hosted plans bundle model access | OpenCatYes — cloud subscription available | GeepsNo — BYOK only |
Yes Partial No
Positioning as of October 2026, from public app-store listings and vendor pages. Full write-up of BayesChat vs Chatbox AI, OpenCat, and Geeps: Read the BYOK client comparison →
FAQ
It's an AI chat app where you bring your own key (BYOK) to connect any provider — OpenAI, Anthropic, Gemini, DeepSeek, or local models — and enable MCP servers so the assistant can act as an agent with tools like web search and fetch. Chat Presets let you switch model, prompt, tools, and memory in one tap.
No. API keys stay in Apple Keychain. Conversations and memories stay on your device. BayesChat has no account system and no cloud that receives your chats.
Turn Memory on in Settings and BayesChat saves the facts worth keeping as you chat; you can add one yourself too. Every memory is listed in Settings, where you can edit or delete it, and you can turn Memory off at any time. Memories live on your device with SwiftData and go only to the provider you configured, as part of the request you send.
Bring your own key. You connect providers with your own API key and pay them directly. We do not resell tokens or sit in the middle of your requests.
Available now on iPhone and iPad; Mac is coming soon. Use OpenAI, Anthropic, Gemini, OpenRouter, DeepSeek, Mistral, LM Studio, Ollama, or any OpenAI-compatible endpoint with a custom URL.
No. BayesChat is free to download. Pro is a one-time $14.99 in-app purchase with lifetime access — no subscription.
Free includes BYOK, on-device storage, streaming Markdown/LaTeX, themes, and basic parameters, with message and provider limits. Pro ($14.99, one time) unlocks unlimited messages and providers, Chat Presets, MCP tools, Memory, custom prompts, advanced parameters, and bulk export.
No. There is no account system — just add your provider and API key and start chatting. Your chats stay on your device, so nothing is tied to your identity.
Yes. You can export conversation history for backups or sharing. History is stored locally on your device via SwiftData.
Not yet. BayesChat currently supports iPhone and iPad; Mac is coming soon. We focus on Apple platforms first and may expand to other platforms later.
Yes. Just add a provider, paste your API key, pick a model, and send a message. For a local model such as Ollama, set its custom base URL and tap Verify.
Model Context Protocol. You can add MCP servers so the model can use external tools such as web search, fetch, or your own JSON-RPC tools — enabled per chat.
Contact Us
Email us about bugs, feature requests, or anything else. We read every message.