ONLYOFFICE is a document collaboration service from Latvia. They offer integrations for several services like SharePoint and Jira as well as self-hosted Cloud services like ownCloud and Nextcloud.
ONLYOFFICE is open source and developed by Ascensio System SIO, headquartered in Riga, Latvia. OnlyOffice is delivered as a SaaS solution or as an installation for private network deployment. They also offer a white label solution.