Best open-source alternatives to Notion

AppFlowy is an open-source workspace application positioned as an alternative to Notion. It is designed for people who want a native, cross-platform productivity tool with stronger control over their data, and it also targets enterprises and builders who want to customize or extend the platform. The project combines Flutter and Rust to provide desktop and mobile clients, with self-hosting support for teams that want to run their own instance. The README highlights collaboration-oriented workplace management, AI capabilities, templates, databases, and documentation-style content, while emphasizing privacy, extensibility, and a community-driven approach to building productivity tools.

AFFiNE is an open-source workspace platform designed for writing, drawing, planning, and organizing knowledge in one place. It combines document editing and whiteboard-style canvas interactions, aiming to serve users who want a Notion- and Miro-like experience in a single product. The project emphasizes a local-first approach, so users keep data on their own devices while still getting real-time sync and collaboration across web and cross-platform clients. It also includes AI-assisted creation workflows, such as turning outlines into slides or summaries into mind maps, and supports self-hosting for teams or individuals who want more control over deployment and data.

Memos is an open-source, self-hosted note-taking application designed for fast, low-friction capture. It is aimed at users who want a simple place to write notes without managing folders, while still keeping data portable through Markdown storage and self-hosting on their own infrastructure. The project emphasizes simplicity and extensibility. It can be deployed with a single Go binary or via Docker, Docker Compose, Kubernetes, or source builds, and it supports SQLite, MySQL, and PostgreSQL. Memos also exposes REST and gRPC APIs for integration, includes zero telemetry, and is positioned as fully open software under the MIT license.

SiYuan is a personal knowledge management application aimed at users who want a privacy-first, block-oriented workspace for notes and knowledge organization. It combines a visual editor with Markdown WYSIWYG support, bidirectional linking, structured content blocks, and a range of knowledge-work features such as databases, flashcards, and document outlining. The project is presented as an ecosystem with desktop, mobile, and browser-extension components, plus a community marketplace and API for integration. It supports Docker deployment and app-market installation, and the README notes that most features are free while some capabilities are reserved for paid members. The software is designed for individual knowledge workers rather than a generic team collaboration platform, but it does expose API access and supports multiple app platforms.

Privacy-first graph-based knowledge management with bidirectional linking and outliner editing

Outline is a team knowledge base application built with React and Node.js. The README presents it as the source code behind the hosted Outline service and positions it for organizations that want to run their own copy or contribute to the project. The project includes documentation for production hosting and local development, along with guidance for debugging, testing, and database migrations. It is oriented toward developers and operators who want to self-host or extend the software, rather than end users looking only for the hosted service. The README also indicates that the software is maintained by a small team and is distributed under the BSL 1.1 license.

Trilium Notes is a cross-platform note-taking application designed for people who want to organize large personal knowledge bases. It emphasizes hierarchical structuring, allowing notes to be arranged in deep trees and reused in multiple places, which makes it suitable for complex personal or research workflows. The project provides both a desktop application and a server-based deployment that can be accessed through a browser or mobile web interface. It includes rich editing, code note support, versioning, sharing, encryption, scripting, and synchronization, giving users a mix of everyday note management and advanced automation. The documentation, mobile access, and self-hosted sync server make it relevant for self-hosters and power users who want control over their notes and data.

Wiki.js is an open source wiki application designed for creating and managing documentation sites. It is positioned as a modern, lightweight, and powerful solution built on Node.js, making it suitable for teams or individuals who want a self-hosted knowledge base or wiki platform. The README highlights official documentation, installation and requirements pages, and a live demo, indicating that the project is intended to be deployed and configured by users rather than used as a hosted SaaS product. It also points to community support channels, translations, and sponsorship information, suggesting an active ecosystem around the core wiki software.

Docmost is an open-source collaborative wiki and documentation platform aimed at teams that need a shared place to write, organize, and maintain knowledge. It combines wiki-style pages with documentation features and emphasizes real-time collaboration for multiple contributors working together. The project highlights spaces, permissions, groups, page history, search, file attachments, embeds, and diagram support, making it suitable for internal documentation, team knowledge bases, and structured collaboration. The README also points users to hosted cloud pricing and to self-hosting/development documentation, suggesting both managed and self-hosted usage paths.

BookStack is an opinionated documentation platform designed for creating, organizing, and storing information in a straightforward way. It is aimed at people who want a simple, intuitive experience for writing and maintaining documentation without needing extensive technical skill. The project emphasizes a stable and easy upgrade path, with optional power features available for users who need more advanced workflows. It is explicitly not intended as a general-purpose extensible platform; instead, it focuses on being a polished self-hosted documentation system backed by official docs, a demo instance, and guidance for customization and development.