What is geocoding-playground?

Geocoding Playground is a tool that runs entirely in your browser and lets you look up addresses, no server required. You can type in a street address or postcode and get back the matching location on a map (forward geocoding), or click anywhere on the map to find the nearest known address (reverse geocoding). What makes it unusual is the scale and approach. It queries a dataset of over 469 million addresses sourced from Overture Maps, a large open geographic data project. Rather than sending your queries to a backend server, the tool runs a real database engine (DuckDB) directly inside your browser using a technology called WebAssembly, and fetches only the relevant slices of the address data files over the internet as needed. Address parsing is country-aware, with dedicated logic for ten countries including the US, Japan, Germany, France, and others. The Japanese parser handles native script and can match addresses written with or without spaces. Street type abbreviations are expanded across 27 languages, so searching "avenue" will also match results stored as "ave." Results appear as markers on an interactive map. Multi-unit buildings show individual unit rows grouped by location so dense city blocks stay readable. The project is split into two parts: a standalone TypeScript library that handles all the geocoding logic and can be embedded in any web app, and a Svelte-based demo interface that showcases it. A live demo is available at walkthru.earth.