MTPLX

The vendor states a 2.24× decode speedup on Qwen3-27B running on an M5 Max MacBook Pro, achieved by using the model's own built-in MTP heads as the drafter — no second model loaded, no external checkpoint to maintain. Acceptance is handled via Leviathan–Chen rejection sampling with a residual (p − q)+ correction, verified bit-exact against single-token autoregressive output. It serves an OpenAI- and Anthropic-compatible API, so downstream tooling like Claude Code, Cline, or the openai-python SDK connects without shims. The wall appears immediately if you leave Apple Silicon: the runtime is explicitly Apple Silicon only, and the custom Metal kernels have no CUDA path.