ONLYOFFICE is an open-source, online office suite that includes editors for documents, spreadsheets, presentations, and forms. It supports all common formats and MS Office files.

Apache OpenOffice is a leading open-source office suite that offers free applications for word processing, spreadsheet, presentations, graphics, databases and more. All data is stored in an open standard format, though Open Office can also read and write files from other common...

CryptPad is a private-by-design alternative to popular office tools and cloud services. All the content stored on CryptPad is encrypted before being sent, which means nobody can access your data unless you give them the keys.

Collabora Online is a powerful LibreOffice-based online office suite with collaborative editing, which supports all major document, spreadsheet and presentation file formats and works in all modern browsers.