I built a native C# Grep engine that's holding it's own with ripgrep (with zero allocations)

Let’s be honest: the golden rule of modern software engineering is "never rewrite grep." Tools like ripgrep are written in native Rust, compiled straight to the metal, and aggressively optimized. For 99% of use cases, wrapping a CLI tool or pulling in a massive external dependency is what people do.

But when you are building an ultra-low-latency AI context layer where sub-20ms execution is the hard ceiling, spinning up external CLI processes, handling inter-process communication, and parsing standard output strings back onto the managed heap destroys performance. The Garbage Collector pressure alone kills your agentic execution loop.

So, I decided to see how close I could get with pure, unadulterated .NET 10.

The result? Glacier.Grep.

On a typical developer workload scanning a 257 MB workspace (590 files), it doesn't just rival ripgrep—it actually beats it on case-sensitive paths.