ONLYOFFICE is an open-source office suite and collaboration platform (documents, spreadsheets, presentations, projects, mail, CRM) developed by Ascensio System SIA. Its code is public on GitHub under AGPL-3.0 with commercial licences for enterprise and developer editions. In 2026 it became the centre of a licensing dispute after a European consortium led by Nextcloud and IONOS launched the Euro-Office fork.