OnlyOffice

OnlyOffice is an open-source office suite developed by Ascensio System SIA, headquartered in Riga, Latvia. Founded in 2009, it provides a comprehensive collaborative document editor that handles text documents, spreadsheets, and presentations with excellent compatibility with Microsoft Office formats (.docx, .xlsx, .pptx). OnlyOffice can be integrated into existing platforms like Nextcloud, ownCloud, and SharePoint, or deployed as a standalone document server. It supports real-time co-authoring, version history, track changes, and comment threads. Available as a self-hosted Community Edition (free and open source) or as a cloud/enterprise solution. OnlyOffice is widely used across European public institutions, schools, and businesses seeking a cost-effective, privacy-respecting Microsoft Office alternative.