
I am a Software Engineer working on open source and enterprise mobile SDKs for iOS and MacOS developers written in Swift. From 🇩🇪 and happily living in 🇺🇸
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I am a Software Engineer working on open source and enterprise mobile SDKs for iOS and MacOS developers written in Swift. From 🇩🇪 and happily living in 🇺🇸
WWDC26 kicked off on June 8, 2026. The information in this article reflects the information published by Apple on that date. There are 14 new frameworks. Name Description AccessoryAccess Manage

WWDC25 kicked off on June 9, 2025. The information in this article reflects the information published by Apple on that date. New Frameworks NameDescription AlarmKitSchedule prominent alarms and countdowns to help people manage their time. AVR...

WWDC25 is almost here, and I couldn’t be more excited! Whether you're attending the official events, community meetups, or just soaking in the energy around Cupertino, there’s no better time to connect, share ideas, and celebrate everything we love a...

In this blog post, I’ll share an observation and advice regarding the caching behavior of network responses by Apple’s APIs. If you are unfamiliar with caching of network responses then I recommend Apple’s article Accessing cached data that introduce...
WWDC24 kicked off on June 10, 2024. The information in this article reflects the information published by Apple on that date. New Frameworks NameDescription AccessorySetupKitUse AccessorySetupKit to discover accessories with Bluetooth or Wi-Fi...

Image you want to write a developer tool for Swift. You probably want to parse, inspect, generate and transform Swift source code.
What are your best options?
Apple provides SourceKit as a framework for supporting IDE features like indexing, syntax-coloring, code-completion, etc. That's how Xcode gets its intelligence. Here is a really good article if you wanna know more about SourceKit.
The gold standard is (was?) SourceKitten , a open source and community-maintained library which significantly reduces the complexity to communicate with SourceKit directly.
It is very popular (~ 1.9k stars on Github) and is used by well-known tools for Swift developers like
But wait! Sourcery recently switched from SourceKit/SourceKitten to SwiftSyntax and announced significant performance improvements.
SwiftSyntax is a set of Swift bindings for the libSyntax library. It allows for Swift tools to parse, inspect, generate, and transform Swift source code.
According to Apple:
Its API is designed for performance critical applications. It uses value types almost exclusively and aims to avoid existential conversions where possible.
There is a really nice Swift Abstract Syntax Tree (AST) visualizer

It looks for me that SwiftSyntax can provide information, which were previously very expensive to obtain in SourceKit/SourceKitten, much faster. For example, SourceKit/SourceKitten has to ask the Swift compiler to determine the runtime name of an inferred type (var hasBasket = false // type is Bool) or to determine the used types within a typealias.
I am planning to evaluate and probably switch from SourceKitten to SwiftSyntax for my open source project SwiftPlantUML.
Then I'll provide feedback about my experience with SwiftSyntax.
This is merely a teaser :)