AI product Open source

Swiftlet

Swiftlet is an open-source Swift and Metal runtime for running Qwen3-Next and Qwen3.5/3.6 mixture-of-experts models locally on Apple devices, including iPhones. It keeps the models' small dense core in memory and streams routed expert weights from storage on demand, allowing 35B and 80B models to run with comparatively low RAM. The project is available as a Swift package, command-line interface, OpenAI-compatible server, and iOS app; its repository describes the runtime as working end to end and notes that only about 3B parameters are active per token in the supported models.

View repository Mentioned in 2 videos ↓

What Swiftlet is used for

2 uses taken from transcripts — each links to the moment in the video.

  • An open-source Swift and Metal runtime for running 35B and 80B Qwen mixture-of-experts models on Apple devices, including iPhones. It is available as a Swift package, CLI, OpenAI-compatible server, and iOS app.

  • Runs large Qwen mixture-of-experts models on Apple devices by keeping the dense core in memory and streaming routed experts from SSD.

Videos mentioning Swiftlet

2 in the library.