TonyBai

Mar 17, 2026 · Fundamentals

Why Go’s regexp Is Slower Than Python – The Safety Trade‑offs Behind the Design

The article dissects why Go’s standard regexp package lags behind Python and other languages, tracing the slowdown to a pure‑Go implementation that avoids CGO, the choice of a Thompson‑NFA engine for safety, heavy UTF‑8 rune decoding, memory‑intensive NFA simulation, and shows how community projects like coregex reclaim performance while preserving Go’s safety guarantees.