iD is the default in-browser map editor on openstreetmap.org, used by the majority of OpenStreetMap contributors. But did you know that many organizations are running customized versions of iD? The iD code is permissively licensed and can be used as a starting point for building a domain-specific map editor or conflation tool. In this session, Bryan Housel, iD project maintainer, discusses the technical architecture of the iD codebase and demonstrates how to create a fork of the iD project and customize it for your needs. Topics include custom presets, cartographic styling, imagery sources, editing tools, and connecting to third-party services.