Team builds custom inference engine in 4 days for $500 in tokens, beats SGLang by 15% with 6 prompts

IgorCarron · x · 2026-11-15

The waterloointern team built a custom inference engine from scratch (literally starting at git init) in 4 days with $500 in token costs, claiming a 15% performance win over SGLang.

The entire build took just 6 prompts — three of which were "carry on," "proceed," and "push to github." The authors note that building a bespoke inference engine per open-source model has become a clear industry trend, driven by a wave of papers earlier this year like hazy research's megakernels and MetaInfer. The core argument against traditional engines like vLLM/SGLang: their abstractions (Triton vs CUDA, Python, etc.) inherently add performance overhead.

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