Open Source Software as a Service (SaaS) Apps

Browse 911 Open Source Software as a Service (SaaS) Apps on AlternativeTo with popular options like Software as a Service (SaaS) and Free.

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  1. Bitwarden icon
     1427 likes

    Open-source password manager with AES-256 encryption and device sync. Store and access encrypted logins across platforms like iOS and Android.

    Cost / License

    • Freemium
    • Open Source

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Self-Hosted
    • Apple Watch
    • Snapcraft
    • Microsoft Edge
    • Vivaldi
    • Google Chrome
    • Flathub
    • Microsoft SQL Server
    • Tor Browser
    • Safari
    • F-Droid
    • Software as a Service (SaaS)
    • Flatpak
    • Cloudron
    • Docker
    • Opera
    • Chocolatey
    • Mono
    • Brave
    • AppImage
    • Mozilla Firefox
    Bitwarden screenshot 1
    Bitwarden screenshot 1
    Bitwarden screenshot 2
    +11
    Bitwarden screenshot 3
    242 alternatives
    4.8
    Excellent182 reviews
  2. ONLYOFFICE icon
     687 likes

    Open-source suite for editing documents, spreadsheets, presentations, forms, and PDF files with co-editing modes, plugin support, AI assistant, and integration across 40+ platforms.

    Cost / License

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Android
    • iPhone
    • Android Tablet
    • HUAWEI AppGallery
    • iPad
    • Self-Hosted
    • AppImageHub
    • Snapcraft
    • Flathub
    • Samsung Galaxy Store
    • Software as a Service (SaaS)
    • Flatpak
    • Cloudron
    OnlyOffice 9.3 Document running in Windows 11
    OnlyOffice 9.3 Spreadsheet running in Windows 11
    ONLYOFFICE screenshot 2
    +13
    ONLYOFFICE screenshot 3
    83 alternatives
    4.2
    Very Good72 reviews
  3. Notesnook icon
     205 likes

    Fully open-source, end-to-end encrypted notes with device-based security, secure sync, offline access, powerful editor, vault, backups, and exports.

    Cost / License

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Google Chrome
    • Flathub
    • F-Droid
    • Software as a Service (SaaS)
    • Flatpak
    • Self-Hosted
    Notesnook screenshot 1
    Notesnook screenshot 1
    Notesnook screenshot 2
    +6
    Notesnook screenshot 3
    352 alternatives
    4.4
    Very Good31 reviews
  4. NextDNS icon
     168 likes

    NextDNS protects you from all kinds of security threats, blocks ads and trackers on websites and in apps and provides a safe and supervised Internet for kids — on all devices and on all networks.

    Cost / License

    • Freemium
    • Open Source (MIT)

    Application types

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Android
    • iPhone
    • Chrome OS
    • BSD
    • iPad
    • UC Browser
    • Vivaldi
    • Google Chrome
    • UniFi Network
    • Safari
    • Yandex Browser
    • Software as a Service (SaaS)
    • OpenWrt
    • Opera
    • Alpine Linux
    • pfSense
    • Mozilla Firefox
    • DD-WRT
    NextDNS screenshot 1
    NextDNS screenshot 1
    NextDNS screenshot 2
    +11
    NextDNS screenshot 3
    142 alternatives
    4.6
    Excellent18 reviews
  5. addy.io icon
     158 likes

    Open-source service offering unlimited anonymous email aliases, encrypted forwarding, spam protection, and anonymous replies to keep your identity private.

    Cost / License

    Platforms

    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Self-Hosted
    • Microsoft Edge
    • Google Chrome
    • Safari
    • F-Droid
    • Software as a Service (SaaS)
    • Mozilla Firefox
    Manage aliases from the dashboard
    The main interface for the Firefox extension
    Settings for the extension
    +1
    Generate Random Chars alias using the extension.
    120 alternatives
    4.7
    Excellent18 reviews
  6. ownCloud icon
     873 likes

    Self-hosted platform for secure file sync, sharing, calendar, and contact management with desktop, mobile, web access, and multi-device syncing.

    Cost / License

    • Freemium
    • Open Source

    Platforms

    • Mac
    • Windows
    • Linux
    • Android
    • iPhone
    • Blackberry
    • Android Tablet
    • iPad
    • Self-Hosted
    • Software as a Service (SaaS)
    • Raspberry Pi
    • Cloudron
    ownCloud screenshot 1
    ownCloud screenshot 1
    ownCloud screenshot 2
    +21
    ownCloud screenshot 3
    230 alternatives
    3.4
    Fair8 reviews
  7. CryptPad icon
     186 likes

    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.

    Cost / License

    Platforms

    • Software as a Service (SaaS)
    • Self-Hosted
    • Cloudron
    Instance homepage
    Markdown slides app
    Code/Markdown app
    +7
    Whiteboard app
    99 alternatives
    4.6
    Excellent21 reviews
  8. Wire icon
     329 likes

    User-friendly messaging platform with end-to-end encrypted chats, voice and video calls, self-deleting messages, file sharing features, and customizable interface.

    Cost / License

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Self-Hosted
    • Snapcraft
    • Flathub
    • F-Droid
    • Software as a Service (SaaS)
    Wire screenshot 1
    Wire screenshot 1
    Wire screenshot 2
    +2
    Wire screenshot 3
    290 alternatives
    4.1
    Very Good21 reviews
  9. Koofr icon
     151 likes

    Koofr is a safe, secure and simple way to store, backup and share your documents, photos, videos and more. It offers up to 10 GB of free safe storage for your files with affordable upgrades and options to connect multiple cloud accounts.

    Cost / License

    • Freemium
    • Open Source (MIT)

    Platforms

    • Mac
    • Linux
    • Online
    • Android
    • iPhone
    • Android Tablet
    • Windows Phone
    • iPad
    • Linux Mobile
    • Google Chrome
    • Rust
    • F-Droid
    • Software as a Service (SaaS)
    • Docker
    • Chromium
    • Mozilla Firefox
    iOS app
    Koofr web app
    Koofr mobile app
    +4
    Koofr mobile app
    202 alternatives
    4.6
    Excellent13 reviews
  10. Docmost icon
     51 likes

    Open-source wiki and documentation platform featuring real-time collaborative editing, spaces, groups, robust permissions, commenting, page history, and fast full-text search.

    Cost / License

    Platforms

    • Software as a Service (SaaS)
    • Self-Hosted
    • Docker
    • Cloudron
    Docmost screenshot 1
    Docmost screenshot 1
    Docmost screenshot 2
    +7
    Docmost screenshot 3
    117 alternatives
  11. Cryptee icon
     112 likes

    Privacy-focused, encrypted and cross-platform data storage for documents, notes, photos, and files with advanced editing, live sync, and open-source features.

    Cost / License

    • Freemium
    • Open Source

    Platforms

    • Online
    • Software as a Service (SaaS)
    Cryptee screenshot 1
    Cryptee screenshot 1
    Cryptee screenshot 2
    +15
    Cryptee screenshot 3
    91 alternatives
    4.4
    Very Good18 reviews
  12. Euria icon
     21 likes

    Privacy-first AI assistant with chat, writing, transcription, summarization, email, and document tools, hosted in Switzerland and compliant with strict data privacy laws.

    Cost / License

    Application types

    Platforms

    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Software as a Service (SaaS)
    Euria screenshot 1
    Euria screenshot 1
    Euria screenshot 2
    +4
    Euria screenshot 3
    82 alternatives
  13. Taiga.io icon
     305 likes

    Agile project management platform supporting Kanban, Scrum, issue tracking, time tracking, customizable workflows, integrations with popular tools, and multilingual support.

    Cost / License

    Platforms

    • Online
    • BSD
    • Self-Hosted
    • Django
    • Angular
    • Software as a Service (SaaS)
    • Cloudron
    Taiga.io screenshot 1
    Taiga.io screenshot 1
    Taiga.io screenshot 2
    +2
    Taiga.io screenshot 3
    35 alternatives
  14. Teable icon
     50 likes

    Teable is a super fast, real-time, professional, developer friendly, no-code database built on Postgres. It uses a simple, spreadsheet-like interface to create complex enterprise-level database applications.

    Cost / License

    • Free Personal
    • Open Source

    Platforms

    • Online
    • Self-Hosted
    • Software as a Service (SaaS)
    • Docker
    Teable screenshot 1
    Teable screenshot 1
    Teable screenshot 2
    +4
    Teable screenshot 3
    83 alternatives
  15. Seafile icon
     196 likes

    Seafile is an open-source file management and collaboration platform that goes beyond sync and share, offering extensible metadata, multi-level tagging, flexible file views, and AI-powered organization for smarter teamwork.

    Cost / License

    • Freemium
    • Open Source

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Self-Hosted
    • Software as a Service (SaaS)
    Seafile screenshot 1
    Seafile screenshot 1
    Seafile screenshot 2
    +4
    Seafile screenshot 3
    131 alternatives
    3.6
    Good7 reviews
  16. Enterprise-ready on-premise suite with advanced word processing, spreadsheet, and presentation tools, maximizing interoperability and file compatibility.

    Cost / License

    • Freemium
    • Open Source

    Platforms

    • Mac
    • Windows
    • Linux
    • Android
    • iPhone
    • Chrome OS
    • Android Tablet
    • iPad
    • Flathub
    • Software as a Service (SaaS)
    • Flatpak
    • Cloudron
    Collabora Office Classic screenshot 1
    Collabora Office Classic screenshot 1
    Collabora Office Classic screenshot 2
    49 alternatives
  17. Rybbit icon
     27 likes

    Open-source analytics software delivering real-time, privacy-focused web metrics with no cookies, intuitive dashboards, customizable filters, and GDPR/CCPA compliance.

    Cost / License

    Application type

    Platforms

    • Online
    • Self-Hosted
    • Software as a Service (SaaS)
    • Docker
    Rybbit screenshot 1
    Rybbit screenshot 1
    Rybbit screenshot 2
    +4
    Rybbit screenshot 3
    69 alternatives
  18. DeepNotes icon
     52 likes

    DeepNotes is an open source, end-to-end encrypted visual note-taking app with deep page navigation and live collaboration. Create mind maps, diagrams, kanban boards, among others. Infinite nesting of infinite canvases.

    Cost / License

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • iPhone
    • Android Tablet
    • iPad
    • Software as a Service (SaaS)
    Family tree
    Diagram
    Kanban
    +5
    History
    115 alternatives
  19. Baserow icon
     73 likes

    Baserow is the secure, open-source platform for building databases, applications, automations, and AI agents — all without code. Trusted by over 150,000 users, Baserow delivers enterprise-grade security with GDPR, HIPAA, and SOC 2 Type II compliance, plus cloud and self-hosted...

    Cost / License

    • Freemium
    • Open Source

    Platforms

    • Online
    • Self-Hosted
    • Kubernetes
    • Software as a Service (SaaS)
    • Cloudron
    • Docker
    • Docker Hub
    Baserow screenshot 1
    Baserow screenshot 1
    Baserow screenshot 2
    +6
    Baserow screenshot 3
    53 alternatives
    3.8
    Good10 reviews
  20. Grist icon
     54 likes

    Transform data with an open-source interface using relational databases and Python engines. Collaborate in real-time with custom permissions for security.

    Cost / License

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Software as a Service (SaaS)
    • Self-Hosted
    • Cloudron
    Grist screenshot 1
    Grist screenshot 1
    Grist screenshot 2
    +4
    Grist screenshot 3
    48 alternatives
    5.0
    Excellent11 reviews
  21. Tiny Tiny RSS icon
     355 likes

    Open source web-based reader with AJAX, offering privacy control through self-hosting. Features include aggregation, keyboard shortcuts, and podcast support.

    Cost / License

    Application types

    Platforms

    • Linux
    • Self-Hosted
    • Software as a Service (SaaS)
    • Cloudron
    Tiny Tiny RSS screenshot 1
    Tiny Tiny RSS screenshot 1
    253 alternatives
    2.4
    Poor8 reviews