Rewriting My CLI Tool in Rust

Why I decided to rewrite a working Python CLI tool in Rust, and what I learned along the way.

Why Rewrite?

The Python version worked, but took 800ms to start. For a tool called hundreds of times a day, those 800ms add up to frustration.

My requirements were simple: fast, single-file distribution, cross-platform. Rust was practically the only choice.

Development Process

The core logic wasn't complex — read config, parse arguments, make HTTP requests, format output. But Rust's ownership model made some things that were one line in Python require actual thought.

// Python: data = json.loads(resp.text)
// Rust:
let data: serde_json::Value = serde_json::from_str(&resp.text()?)?;

At first it felt verbose. After writing more, I realized the bugs the compiler catches save far more debugging time than the extra keystrokes cost.

Results

Startup time dropped from 800ms to 12ms. Single binary file at 4.2MB, zero dependencies.

Writing code isn't about proving which language is better — it's about picking the right tool for the job.