Cold-Start

In Part 2 I measured the cold start of a minimal Rust Lambda at 18 to 22 ms. This post breaks down what that init window is actually paying for, and which parts you can move. The short version: out of the four phases that make up a cold start, only two are under your control. The rest is AWS infrastructure that you inherit whether you like it or not. The Four Phases ...

In Part 1 I covered why Rust on AWS Lambda is worth exploring and laid out the project setup. This post measures the one number that matters most for serverless latency: cold start time. To get a clean floor measurement, I used the simplest possible endpoint with no database, no external calls, and no middleware. The Benchmark Setup The handler is a single health endpoint built with Axum and Cargo Lambda: ...