Coding

Pragmatic notes on developer tools, languages, and workflows. Shortcuts, tricks, and lessons from actually shipping code.

Feature flags DIY: 100-line SDK vs. LaunchDarkly cost

Build lightweight feature flags with JSON config and environment variables. Enable gradual rollouts and kill switches without an expensive SaaS.

Build professional terminal UIs with Textual: a Python framework with CSS styling, reactive widgets, and async events for dashboards and dev tools.

Profile and optimize Python memory with memray, tracemalloc, and objgraph. Covers leak detection, generators, __slots__, and cutting peak use.

Host a private PyPI registry with pypiserver and a local npm registry with Verdaccio to cache Python and Node packages. Setup takes under 30 minutes.

Test your Python code against real PostgreSQL, Redis, and Kafka containers with Testcontainers and pytest. Drop the mocks for real services.

Hypothesis generates hundreds of random inputs to find bugs example-based tests miss, then shrinks to the smallest failing case. Works with pytest.