Potlatch is described as '2 is the OpenStreetMap editor you get when you click on the 'Edit' tab' and is a Map Service in the Travel & Location category. There are eight alternatives to Potlatch, not only websites but also apps for a variety of platforms, including Android, Windows, Linux and Mac. The best alternative is StreetComplete, which is both free and Open Source. Other great sites and apps similar to Potlatch are JOSM (Free, Open Source), iD (Free, Open Source), Vespucci (Free, Open Source) and Osmosis (Free).
Vespucci is the first OpenStreetMap editor for Android, Codename "Vespucci", continuously improved and developed since 2009. It supports the full OpenStreetMap data model including lots of less known quirks and can be used, if necessary, completely offline.
MapComplete is an OpenStreetMap viewer and editor. It shows map features on a certain topic, and allows to see, edit and add new features to the map. It can be seen as a webversion crossover of StreetComplete and MapContrib.
The Openstreetmap Contributor app allows anyone to contribute to OSM. It enables those-who-know to easily manage a group of newbies as the contribution process is intuitive and easy. Bring your MapParties to a whole new level!.