Graith CTS
A mobile transfer engine that finishes the job.
A patent-pending, cross-platform mobile transfer system delivered as an SDK. One written spec is implemented twice, in Swift and Kotlin, and both must pass the same shared test suite.
- Role
- Spec, architecture and both SDKs
- Status
- Patent pending. The SDK is not licensed publicly.
- Built with
- Swift
- Kotlin
- URLSession and Cronet
- BGContinuedProcessingTask
- WorkManager
Why it exists
Phones suspend background work as soon as you switch apps. Large uploads fail and restart. Graith keeps a transfer alive when the app sleeps, the network changes or the login expires.
What it does
- Three fallback tiers: HTTP/3 in the foreground, extended background time on iOS 26 and Android, and an OS-survivable fallback with a resume journal.
- Parallel multipart uploads of up to 10,000 parts, ranged downloads and adaptive concurrency.
- Recovers from an expired session mid-transfer without starting over.
How it’s built
- Built on BGContinuedProcessingTask, the background-processing API Apple introduced in iOS 26.
- Android builds with and without Google Play services, embedding Cronet on devices that lack it.
- Committed benchmark baselines gate every merge, so a slower build does not ship.