Why I made a keyboard for my iPhone Duo
By Patrick Gatewood,
In short: Duoboard is a keyboard for the iPhone Duo. Open, it keeps the keys under one thumb with emoji, numbers, suggestions, snippets and your clipboard on the other screen, splits them in portrait, or puts a keyboard under each thumb. It also has swipe typing, autocorrect and a space bar trackpad. Free to download; Pro is free for 7 days, then $1.99 once. No subscription, and the keyboard never uses the network.
I love my iPhone Duo. Closed, it's a phone. Open, it's two apps side by side, and most days I have Messages on one half and whatever I'm actually doing on the other.
The one thing that bugged me from the first day was typing. When you open the Duo, the keyboard stretches across both screens, and my hands aren't big enough to type across it. It never made sense to me, either: I was working in one half of the screen, so why was I typing on a keyboard the width of both? Apple does have a split keyboard, but only in landscape, and it's tucked behind the More button. I tried it. It didn't work for my hands either.
So at the end of October I started building my own. I'm a solo developer, and I make small apps under the name Robot Hand.
One screen for the keys
The first idea was simple: if I'm working in half the screen, the keyboard should be half the screen too. Duoboard's Half keeps the keys on the screen you're typing on, and the app on the other half stays in view instead of disappearing behind a giant keyboard.
Then I wanted it under one thumb. Flick again and the keys tuck in toward the edge you're holding, close enough to type one-handed with whichever hand has the phone. When I switch hands, a tap on Move keyboard here sends the keys to the other side.
The other screen, the sidekick
That worked. But it left half the keyboard area empty, and an empty half screen on a phone like this felt like a waste. So I filled it with everything I'd ever wanted from a keyboard:
- Emoji you can search, right next to the letters, so you don't lose your place.
- A real number pad, and search for any symbol you can name.
- Nine word suggestions instead of three.
- Snippets for things I type all the time, like my address.
- My clipboard, a tap away.
- Duoboard's settings, a tap away too.
I call that other screen the sidekick. It's my favorite part.
Everything is a gesture
I didn't want to dig through menus to change layouts, so every move has a gesture. On the open Duo:
- Flick the space bar toward an edge, or sweep two fingers that way: the keys move into Half on that screen, with the sidekick beside them.
- Flick that way again for one hand: the keys tuck in under your thumb.
- Flick toward your thumb once more and the word suggestions slide over to it, so you don't have to reach.
- Flick back the other way to return to the full width of that screen.
- Spread two fingers apart on the keys to split them, one half under each thumb. Pinch to bring them back together.
- Swipe a word in one stroke, or tap it out.
- Hold the space bar and slide to move the cursor. The higher your thumb, the faster it goes.
- Hold the emoji key to pick which side the keys go on, and hold 123 to type snake_case, kebab-case, camelCase or a path.
And if your thumbs want the keys bigger or smaller, the Size menu lets you drag them to any size.
Making the keys feel right
The rest of the work was making the keys feel right: swipe typing that keeps up, autocorrect that learns your words and pulls run-together words apart, and suggestions that know today's words, like ChatGPT and Venmo. I tested on my own Duo every day, and a friend with a Duo tested builds from afar.
A split for two thumbs
When I read what other Duo owners were saying online, a lot of them wanted something I hadn't built: a split keyboard, one half under each thumb. That wasn't my problem, but it's a fair one, so Duoboard 1.1 adds it. Spread two fingers on the keyboard to split it, and pinch to bring it back together. Unlike Apple's, it works in portrait, and you can drag the halves as wide as your thumbs like.
There's also Dual, a whole keyboard under each thumb, and Full, the classic layout across both screens.
A few things I care about
- Nothing you type leaves your phone. The keyboard never uses the network, and there's no account.
- It's not a subscription. The full-width keyboard, autocorrect, emoji and snippets are free. The open-Duo layouts and swipe typing are Pro: free for a week, then $1.99 once.
- On a regular iPhone, or on the Duo's outer screen, it's a normal keyboard.
If you have a Duo, I'd love for you to try it. If you love it, great. If you don't, tell me what you'd want changed. I read everything that comes in at hello@robothand.dev, and a lot of what's in 1.1 started as someone's complaint.
