Best BYOK AI chat apps: 5 of 9 keep your API key on your device

Which BYOK AI chat app is best in October 2026?

Two of the nine apps send your requests through somebody else's servers. A BYOK (bring your own key) app is only the window. You paste an API key from OpenAI, Anthropic, Google or OpenRouter, and that lab bills you per token. So the apps differ on four things: the price of the app, whose keys it takes, where it keeps your key, and whether it works on a phone. We read each one's own pricing page, docs or source code on 12 October 2026.

Where the key lives is the difference that matters if anything leaks. TypingMind's privacy policy is blunt about it: "Your API keys are stored locally on your device and are never transmitted to our servers." Raycast is the opposite case. Its manual says requests made with Anthropic, Google and OpenAI keys go through Raycast's servers "in order to unify the model APIs". Only an OpenRouter key goes direct.

Here's the pick by job, from those pages:

• Best for most people: Chatbox. The apps are free, they're native on iOS, Android, Windows, Mac and Linux, and they take keys from OpenAI, Anthropic, Gemini, DeepSeek, xAI, Mistral and OpenRouter.
• Best paid app: TypingMind. You pay $39 once, and your key stays in the browser.
• Best on a Mac: BoltAI, from $79 once, which keeps keys in the macOS Keychain.
• Best for a team you host: LibreChat. It's free under the MIT license, and each person's key sits encrypted in your own database.
• Best next to local models: Open WebUI, which runs Ollama beside your cloud keys.
• Best on Android with one key: Aiyo, free on F-Droid, with OpenRouter as its only provider.

How do BYOK chat apps compare on price, providers, key storage and mobile?

Five of the nine apps have a free way in, and the paid ones split between one payment and a subscription. Prices are in US dollars, read from each vendor's own page on 12 October 2026. None of them includes the API bill itself.

Two prices in that table won't hold still. TypingMind's checkout page shows Premium at $99 with $198 struck through and a "50% OFF" label, so check it before you buy. Each TypingMind license works on 5 devices. BoltAI's $79 Essential covers 1 device and one year of updates, and its pricing page says Pro adds 2 desktops and 1 mobile device.

The free apps aren't all free in the same way. Chatbox's pricing file says "Users can also use their own API keys with the free Chatbox apps." LibreChat and Open WebUI are free, but you run them on a server you pay for. Open WebUI also changed its license in April 2025: a deployment with more than 50 users in 30 days may not remove the Open WebUI branding without an enterprise license, according to its license page.

Where does a BYOK app store your API key?

A BYOK app stores your key in one of three places: your own device, a server you run, or the vendor's server. That choice decides who could read the key if something leaks.

On the device, TypingMind writes the key to the browser's Local Storage and IndexedDB, and chat requests go straight from your browser to the AI provider. You can also encrypt that stored data with a password of your own. One exception: a provider that blocks browser calls needs TypingMind's optional proxy, which you switch on yourself. BoltAI writes your OpenAI key to the macOS Keychain and encrypts other keys with a key that also sits in the Keychain. Its own post adds: "There is no intermediate server." Chatbox's privacy page says all your chat messages and settings data stay on your device, and the key is one of those settings. Msty Studio Desktop stores its data on your computer, and Studio Web uses the browser's storage instead. Aiyo's F-Droid page only says the app collects nothing, so we read its source: it saves the OpenRouter key to an encrypted store on the phone.

On a server, LibreChat is the clearest case. We read its source on 12 October 2026. The key methods encrypt each user's key before it's saved to MongoDB, and a key can carry an expiry date. The schema puts a TTL index on that date, so the database deletes an expired key on its own. That's handy for a class or a team that shares one server. Patch it, though. CVE-2026-31942, published in June 2026, let any signed in user overwrite another user's API keys. LibreChat fixed it in version 0.8.3, released in March 2026, so run that or later.

Open WebUI does both. An admin normally enters keys under Settings, Admin, Connections, and they're saved on the server. Its experimental Direct Connections mode keeps a user's own key in the browser's local storage and calls the provider directly, but an admin has to turn it on first. OpenRouter keeps provider keys encrypted on its side, since routing your calls is the whole point of it.

Which BYOK chat apps work on iPhone and Android?

Chatbox is the only one of the nine with native apps on both iOS and Android. Its GitHub page links the App Store and Google Play builds, and it says "Your data remains on your device." Raycast has an iOS app, and its BYOK feature covers it, per its manual.

TypingMind has no app store app. Its install guide puts it as a web app on the home screen, from Safari on iOS or Chrome on Android. BoltAI's iPhone and iPad app is still a beta. Aiyo is Android only, version 7 or newer, and it needs an OpenRouter key. Msty Studio has no phone app at all. LibreChat and Open WebUI open in any phone browser once your server is running.

Is bringing your own API key cheaper than ChatGPT Plus?

Yes, for most people who chat a few dozen times a day. ChatGPT Plus is $20 a month. The same $20 of API credit buys about 2,857 standard answers from GPT-6.1 Sol at OpenRouter's list price, read on 12 October 2026. A standard answer here is 1,000 tokens in and 500 out, the mix Whizi's cost index uses.

Long chats cost more than that table suggests. Every follow up sends the whole conversation again as input, so the 20th message in a thread can cost several times the first. Your Plus plan won't pay for any of it. OpenAI's Plus help page says "API usage is separate and billed independently." OpenAI's Sign in with ChatGPT does let a Plus plan cover requests in a short partner list (Notion, Warp and Vercel among them in October 2026), but none of these nine is on it. So a BYOK app needs a funded API account. The ChatGPT API vs subscription breakdown works out where the two meet.

Do you need an OpenRouter key or one key from each lab?

One OpenRouter key is the simplest setup, because it reaches models from every major lab through one bill. TypingMind, Chatbox, Msty, Raycast and Aiyo all list OpenRouter as a provider. OpenRouter charges a 5.5% fee when you buy credits on its Standard plan, per its pricing page, and its free tier opens 25+ free models at 50 requests a day.

Keys from each lab skip that fee. You can also do both. OpenRouter's own BYOK feature lets you store an OpenAI or Bedrock key there, with no fee on the first $25,000 of list price use a month and 5% after. The OpenRouter alternatives page covers who else sells one key for many models.

When is a BYOK chat app the wrong choice?

A BYOK app is the wrong choice when you don't want to run API billing at all. Whizi, which publishes this page, takes no API keys. Its plans bundle 280+ models from $15.99 a month, and Pro gives 2,500 credits for $29.99. It loses on price for heavy Claude users: that's 250 Claude Sonnet messages on Pro, while $20 on your own key covers about 2,857 standard Sonnet answers. The TypingMind alternative page sets the two models side by side, and pricing lists what each plan carries.