Announcing OTPKit: The First Open Source Trip Planner for iOS
I’m thrilled to announce the release of OTPKit, a modern OpenTripPlanner library for iOS written entirely in Swift. This is a significant milestone for the OneBusAway project and, frankly, for the entire open source transit software ecosystem.
Why OTPKit Matters
For over a decade, the number one feature request for OneBusAway on iOS has been trip planning. Riders didn’t just want to know when their bus was arriving—they wanted to know how to get from point A to point B using public transit. It sounds simple enough, but building a production-quality trip planner for iOS is a massive undertaking.
Until now, if you wanted to integrate OpenTripPlanner into an iOS app, your options were limited. You could build something from scratch, license a proprietary solution, or make do without. There simply wasn’t a modern, open source OTP framework for iOS.
OTPKit changes that.
The Only Modern, Open Source OTP Framework for iOS
OTPKit is the first and only Apache 2.0-licensed OpenTripPlanner client library for iOS. It’s designed from the ground up to be:
- Easy to integrate: Available as a Swift Package, OTPKit drops into any iOS project with just a few lines of code.
- Production-ready: This isn’t a proof of concept. OTPKit powers trip planning in the OneBusAway iOS app, serving hundreds of thousands of riders.
- Beautifully designed: We’ve built UI components that match the quality riders expect from modern iOS apps, including Apple Maps-style intermediate stop annotations and intuitive navigation flows.
- Fully open source: Licensed under Apache 2.0, OTPKit is free to use, modify, and distribute. Any transit agency or developer can integrate it into their own applications.
A New Standard for the Industry
The lack of open source trip planning options on iOS has been a real barrier for transit agencies and developers. Proprietary solutions are expensive, and building from scratch requires significant engineering resources that most organizations simply don’t have.
OTPKit lowers that barrier dramatically. Now, any transit agency can offer their riders a first-class trip planning experience on iOS without paying licensing fees or building custom infrastructure. Any developer can build innovative transit applications that include full journey planning capabilities.
This is the kind of foundational infrastructure that makes the entire open transit ecosystem stronger.
A Google Summer of Code Success Story
OTPKit began as a Google Summer of Code project in 2024. Hilmy Veradin, a talented developer from Jakarta, Indonesia, laid the groundwork by creating the initial library architecture, implementing core networking and data models, and successfully integrating an MVP into the OneBusAway iOS app. His work proved that this ambitious project was not only possible but could be executed with excellence.
In 2025, Manu R picked up the torch and continued building on Hilmy’s foundation. Manu—a final-year Computer Science student from India and a WWDC 2025 Swift Student Challenge winner—brought fresh ideas and impressive technical skills to the project. His contributions helped transform OTPKit from a promising prototype into a polished, production-ready library.
A huge thank you to both Hilmy and Manu for their outstanding contributions. Google Summer of Code continues to be an incredible program for fostering open source talent, and we’re proud to have been part of it.
Thank You to Our Contributors
Open source projects thrive because of their communities. I want to extend my sincere thanks to everyone who has contributed to OTPKit:
| Contributor | First Contribution |
|---|---|
| Hilmy Veradin | May 2024 |
| Manu R | September 2025 |
| Mayukh Baidya | November 2025 |
Your work is making a real difference for transit riders around the world.
Get Involved
OTPKit is open source, and we welcome contributions from developers of all skill levels:
- Check out the source code: https://github.com/OneBusAway/OTPKit
- Report issues or suggest improvements through our issue tracker
- Join the conversation on our onebusaway-developers mailing list
Whether you’re a transit agency looking to add trip planning to your app, a developer interested in contributing, or just someone who cares about open source transit software, we’d love to hear from you.
Aaron Brethorst Executive Director, Open Transit Software Foundation