Metal 4 API Reference

Overview

Metal 4 is a ground-up API redesign — not a minor version bump. It introduces the MTL4 prefix (ObjC protocols/classes) / MTL4:: namespace (metal-cpp). All Metal 4 objects are created from MTLDevice / MTL::Device. Key removals: blit encoder, parallel render encoder, set*Bytes, managed storage mode, per-encoder resource binding, addCompletedHandler.

Metal 4 requires macOS 26+, iOS 26+. Feature detection:

// ObjC
if ([device supportsFamily:MTLGPUFamilyMetal4]) { /* Metal 4 path */ }

// metal-cpp
if (device->supportsFamily(MTL::GPUFamilyMetal4)) { /* Metal 4 path */ }

Metal 4 can coexist with Metal 3 queues in the same app for incremental adoption.