Back in October, SwiftKey announced that its popular predictive Android keyboard would soon feature something called SwiftKey Flow — the company's answer to Swype and Google's own gesture-based typing solutions, which both let you enter words by sliding your finger from letter to letter in a continuous motion. Today SwiftKey Flow has been made available to all as part of SwiftKey 4: it's a free upgrade for existing users, and the app is currently on sale at $1.99 for everyone else. The Flow functionality has also been added to the tablet version of SwiftKey.

It's shocking how fast everything reacts to your input

We've been using SwiftKey 4 for a few days, and overall we're very impressed. The new Flow feature works seamlessly with SwiftKey's tried-and-true prediction engine, and it's actually a little shocking how fast everything reacts to your input — the keyboard not only selects words accurately even from the most haphazard of swipes, but predicts the most likely upcoming word as well. And, if SwiftKey guesses the word you're swiping before you're finished, you can simply lift your finger off the screen to select it. You can also swipe down to the space bar to break up words, making it possible to type a whole sentence without taking your finger off the glass.

Most importantly, the addition of Flow doesn't seem to have impacted the responsiveness of regular typing at all, and there are some times you'll want to do that — Flow isn't quite as reliable with very long words, for example. SwiftKey 4 may not be for everyone; it requires you to master an unusual rhythm of taps, swipes, and traditional typing to get the most out of it, but once it clicks? We'd say it's the fastest text entry system available on a phone.