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TALKING TO JSI IN SWIFT: WHAT CHANGED IN SDK 56

expo.dev15 min read

Summary from the TLDR Dev newsletter

Expo SDK 56 has an architectural rewrite for native modules on Apple platforms by allowing Swift to communicate directly with JSI. This change removes the previous Objective-C++ middleware, resulting in performance gains between 1.6 and 2.3 times faster than older versions. By using Swift 5.9's C++ interoperability and non-copyable types, the new system has strict memory safety while simplifying the internal development stack.