We needed rate limiting across all our services: FastAPI, Django, you name it. The usual approach is to grab a library, wire it up per-framework, and accept the slight differences in behavior between them. We went a different way: one Lua script that runs atomically in Redis, with everything else being thin wrappers around it.

This is how the rate limiting system in application-kit works, including per-project overrides, element-based counting, and a monitor mode for gradual rollouts.

Our Python services ran on ubuntu:24.04 with pip-installed dependencies. It worked, but the images carried hundreds of packages we never used, Trivy scans were noisy with OS-level CVEs, and builds were slower than they needed to be. Over a couple of months we migrated to Chainguard’s Wolfi base image and uv for dependency management. This is how it went for the maps service, the one that renders static map tiles with a C++/Python hybrid stack.

Generating Mapbox GL GL style JSON from Python code instead of editing 3,000-line JSON files by hand. Hierarchical style resolution, a Django-style filter DSL, injection-based layer ordering, and a Go sprite generator called from Python via ctypes.

The problem with style JSON

A Mapbox GL GL style is a single JSON file that describes everything about how a map looks. Background color, road widths at every zoom level, label fonts, icon placement, landcover tints, building extrusion heights. All of it.