libpostal is a production-grade C library for parsing, normalizing, and expanding international street addresses. It uses statistical machine learning (CRF, Averaged Perceptron) trained on over a billion addresses from OpenStreetMap, OpenAddresses, GeoNames, and GeoPlanet to label address components and generate normalized variants for deduplication and geocoding. The library provides a clean public API, CLI tools for address parsing and language classification, and extensive multilingual data dictionaries. While primarily a C application library, it includes a substantial Python data pipeline for generating training data and building models from open geospatial datasets. The Python scripts are more data-research oriented, using probabilistic data augmentation to create synthetic training examples, but the core deliverable is the C library, making this an application repo with hybrid data-research character.