FiftyThree SDK
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Open up new ways for users to interact with your app by integrating Pencil, the award-winning Bluetooth stylus from FiftyThree. The FiftyThree SDK lets you take advantage of industry leading features such as palm rejection, advanced touch classification, and effortless Bluetooth pairing.

Drawing and Beyond

Bring the best stylus experience to your game, document editor, creativity app, or museum installation.


Pencil makes the most realistic drawing app even easier to use by combining all three of its key features—Paint, Smudge, and Erase—into one intuitive tool.



The best note-taking app just got better. Pencil integration brings leading palm rejection technology for easy handwriting, as well as flip-to-erase.



Pencil adds a new dimension of playful interactivity to this popular musical app. Draw musical strings with Pencil; pluck them with your fingers; cut them with the eraser.

Coming soon!

Hardware built for software

FiftyThree's products are renowned for their craft, simplicity, and expressiveness. We put these same values into the design of our SDK. FiftyThree SDK was made to integrate painlessly into your app and unlock powerful creative possibilities.

Pencil and touch classifiers

Pencil opens up interaction possibilities beyond multitouch. Through the FiftyThree SDK, touches are classified as a pen, eraser, finger, or palm. Navigate with a finger, edit with the tip, delete with the eraser—more inputs mean more interaction possibilities.

Handling classification of touches:

// Implement FTTouchClassificationsChangedDelegate protocol in your UIViewController.// Once per frame, you will receive a collection of all the touches whose classification has changed that you'll need to process e.g.,- (void)classificationsDidChangeForTouches:(NSSet *)touches{for(FTTouchClassificationInfo *info in touches){// Your app might:
// 1. Render lines that have been classified as "pen".
// 2. Use touches that have been classified as "finger" for gestures.
// 3. Take a photo for touches that have been classified as "eraser".}}

Technical Requirements

Hardware: iPad 3+, iPad Mini, iPhone 4S+Software: iOS 7.0+, XCode 5.0+

"It’s been fantastic collaborating with a team so like-minded, and we really admire what FiftyThree has been able to achieve in the design of Pencil and Paper. After months of collaboration, we’re excited to offer Procreate artists a beautifully simple, yet powerful Pencil integration."

James Cuda, Savage Interactive CEO

True Partnership

We'll give you everything you need to build something great.

Request access to FiftyThree SDK by applying for our partner program.

FiftyThree SDK Partner Program

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