AppFlowy stands out as the best open source alternative to Microsoft OneNote. If it doesn’t meet your needs, don’t worry, — we’ve put together a ranked list of other open source Microsoft OneNote alternatives to help you find the right fit. Other interesting open source alternative to Microsoft OneNote is Affine.
Microsoft OneNote alternatives are mainly Note Taking but may also be Project Management or Task Management. Browse these if you want a narrower list of alternatives or looking for a specific functionality of Microsoft OneNote.
An open-source alternative to Notion, offering a productivity platform designed for managing projects, tasks, and knowledge bases.

AppFlowy is a customizable, privacy-focused project management and collaboration platform. It empowers teams and individuals to manage tasks, wikis, and projects while retaining full control of their data. Ideal for users seeking flexibility, privacy, and powerful AI-enhanced productivity tools.
Key benefits of AppFlowy include:
An open-source, all-in-one productivity platform that combines documents, whiteboards, and databases into a unified workspace.

AFFiNE is an open-source, privacy-first KnowledgeOS that seamlessly combines documents, whiteboards, and databases into a unified workspace. Designed for individuals and teams, it offers a flexible platform to write, draw, and plan, enhancing productivity and creativity.
Key benefits of AFFiNE include:
Unified Workspace: Integrates docs, whiteboards, and databases, allowing seamless transitions between writing, visualizing, and organizing tasks.
Block-Based Architecture: Enables dynamic content creation with reusable, linkable blocks, facilitating efficient knowledge management.
Privacy-Focused & Open-Source: Offers self-hosting options and local-first data storage, ensuring complete control over your information.
Cross-Platform Compatibility: Built with web technologies, AFFiNE runs smoothly on Windows, macOS, and Linux, providing a consistent experience across devices.
Flexible Views & Real-Time Collaboration: Supports multiple views like Kanban and whiteboard modes, with real-time syncing for collaborative work.
A powerful photo editing and illustration tool that enables users to transform images, remove unwanted elements with a click, and create photorealistic results using generative fill tools.
A web analytics service offered by Google that tracks and reports website traffic, providing insights into user behavior.
An all-in-one workspace for notes, tasks, databases, project management, knowledge sharing, and team collaboration, blending flexibility with organization to streamline your workflow.
Google’s mobile and web app development platform that helps developers build apps and games that users will love.
A customer service platform that combines live chat, messaging, and AI-powered support tools. It helps businesses manage customer interactions, automate responses, and improve support efficiency across channels.
A centralized collaboration platform that connects the right people, resources, and tools to streamline teamwork and achieve goals effectively within organizations or teams.