KeyAI: What Is the AI Keyboard Everyone's Searching?

TL;DR: KeyAI is a third-party AI keyboard for iPhone that fixes spelling and grammar, rewrites tone, translates, and drafts replies in over 60 languages, inside any app you already use. It costs $39.99 a year or $59.99 for life, after a 3-day free trial with no card.

What is KeyAI and how does it work?

If you searched “keyai,” you probably saw it mentioned somewhere and wanted to know what it actually does before installing anything. Short version: KeyAI is an iOS keyboard app. Once you turn it on, it replaces the stock iPhone keyboard (or sits alongside it) and adds a row of AI tools above the keys.

Those tools include spelling and grammar fixes that read the whole sentence instead of one word at a time, tone rewriting (make a message sound more formal, friendlier, or shorter), paraphrasing, translation across 60+ languages, and an ask-AI mode that drafts a reply based on what you’re responding to. You tap the tool you want, KeyAI sends the text you’re working with to its AI model, and the suggestion appears in a few seconds.

The reason people end up asking “what is keyai” instead of already knowing is that it isn’t a system feature. It’s a separate download that has to be added as a keyboard, which is a step Apple buries a few menus deep. Once it’s added, it works the same way in Messages, WhatsApp, Mail, Notes, Instagram, dating apps, or anywhere else you can type, because the keyboard sits at the iOS layer, not inside one app.

That’s a different model than most people expect from a keyboard app. A regular third-party keyboard swaps out the keys and maybe adds better emoji or a different layout. KeyAI still does that job, but the AI row above the keys is the part people are actually searching for: a fix suggestion, a shorter version of a paragraph you just typed, or a translated version of a message someone sent you in another language, all without leaving the app you’re typing in.

Which iPhones does KeyAI support?

KeyAI doesn’t require a specific chip or an Apple Intelligence-capable device. Any iPhone that can run current iOS and install third-party keyboard extensions can run KeyAI, which includes models several years older than what Apple’s own AI writing tools require.

That distinction matters more than it sounds. Apple Intelligence’s Writing Tools only work on iPhone 15 Pro and later, so anyone on an iPhone 14, 13, or older gets left out of Apple’s on-device AI proofreading entirely. One iPhone 14 Pro owner put it bluntly on Reddit after asking Apple support about a related feature:

“I thought Apple Intelligence wasn’t even out yet?” (via r/ios discussion on iOS 18 AI features)

Because KeyAI runs its AI in the cloud rather than requiring on-device silicon, it doesn’t split users by hardware generation the same way. The tradeoff is that it needs an internet connection to reach its model, the same way any cloud-based AI tool does.

How do I install the KeyAI keyboard?

Setup follows the same pattern as any third-party iOS keyboard. It’s a few taps, but one step trips people up more than the rest.

1. Download KeyAI from the App Store.
2. Open Settings, General, Keyboard, Keyboards, Add New Keyboard and select KeyAI.
3. Tap KeyAI’s name in the keyboard list and turn on Allow Full Access. Skip this and the AI tools have no way to reach KeyAI’s servers, so nothing will work.
4. In any app, long-press the globe icon (🌐) on the keyboard and choose KeyAI from the list.

From there, type as usual. The AI tools sit above the keys, and you tap one when you want a fix, a rewrite, or a translation, instead of every keystroke going through an AI pass.

For screenshots of each screen, see how to add an AI keyboard to iPhone.

Is KeyAI free to use?

Not permanently, but you can try the whole thing before paying. KeyAI runs a 3-day free trial with no credit card needed, so every tool, including translation and tone rewriting, is available from the first install.

After the trial, KeyAI costs $39.99 a year or $59.99 as a single lifetime payment. There’s no separate free tier with reduced features; once the trial ends, a subscription is required to keep using it.

If cost is the main question before you commit, it’s worth comparing that against what’s already on your phone for free. Apple Intelligence Proofread is free on supported hardware for English, and iOS autocorrect is free everywhere but weak outside single-word fixes. The best free AI keyboard options for iPhone breaks down what each free tool actually covers versus what needs a paid keyboard like KeyAI.

How does KeyAI compare to other AI keyboards?

KeyAI’s main differentiator is breadth: it bundles ten-plus tools into one keyboard instead of specializing in just spelling or just tone. Here’s how it lines up against the other common options:

Grammarly’s keyboard is free and handles English grammar reasonably well, but a number of users have reported it misbehaving on iPhone, including one longtime subscriber who said Grammarly told them a document was “perfect” while it was full of errors. Gboard is solid for typing and prediction but doesn’t rewrite tone or translate inline. Apple’s own tools are free and improving, but they’re locked to newer hardware and mostly English.

For anyone who writes in more than one language, or who wants tone changes and translation without switching apps, KeyAI’s combination of breadth and hardware compatibility is the reason it keeps coming up in these searches. It’s worth being clear about the tradeoffs too: KeyAI needs a connection to reach its AI model, so it won’t fix a typo mid-flight with no signal, and Full Access is a real requirement, not an optional toggle. Neither is unusual for this category, but both are worth knowing before you install it expecting something that works exactly like the built-in keyboard.

See the full lineup, including apps that specialize in just one of these features, in the 10 best AI keyboards for iPhone in 2026.

Try KeyAI free for 3 days, no card →