OpenStreetMap is a free, open source map of the world that anyone can contribute to. It is used by millions of people around the globe and powers some of the largest websites and apps in the world. Hiring an OpenStreetMap developer gives you access to someone with intimate knowledge of how the map works and how to make changes to it. They can also help you take advantage of all the data that is available through OpenStreetMap, including real-time updates, historical data, and more.