OneNote is free, but it keeps your notebooks inside the Microsoft ecosystem: storage lives in OneDrive, the file format is proprietary, and getting years of notes back out is notoriously painful. The open source alternatives below store notes in open formats and sync them through services you choose - or a server you run - with no Microsoft account required.
The closest replacements keep the familiar notebooks-and-sections model with apps on every desktop and mobile platform, and several add end-to-end encrypted sync. Everything stays exportable, so the next migration is a copy, not a rescue mission.
Memos is an open-source, self-hosted note-taking tool for quick capture. It provides a timeline-first interface for notes, daily logs, links, and snippets, so you can open it, write, and move on without navigating folders. Notes are stored in Markdown and kept on your infrastructure, with zero telemetry.
Joplin is a free, open source note taking and to-do application for Windows, macOS, Linux, Android, and iOS. It handles large note collections organized into notebooks, with searchable Markdown notes that can be copied, tagged, and edited in the apps or in your own text editor. It is offline first, so notes stay on your phone or computer and remain available without internet.
Xournal++ is handwriting note-taking software for annotating PDFs and writing on digital paper backgrounds. It is built for people who work with a stylus, letting you write, draw, and mark up documents by hand and store the results in the .xopp file format.
Notesnook is a free and open-source note-taking app positioned as an end-to-end encrypted alternative to Evernote. It focuses on user privacy and ease of use, with zero knowledge principles so notes are encrypted on your device before leaving it.
TiddlyWiki is a non-linear personal web notebook for people who want a wiki they can keep forever, independently of any corporation. It is a complete interactive wiki in JavaScript that solves note taking and linked writing in a self-contained format.
GitJournal is a mobile-first note taking app built around privacy and data portability. It stores notes as standardized Markdown with an optional YAML header, then keeps them in a Git repo of your choice - GitHub, GitLab, or a custom provider. That means you can self-host your notes or host them with any Git provider you trust.
Heimer is a desktop application for creating mind maps, diagrams, and note-taking layouts. It is written in Qt and targets Linux and Windows, with an easy-to-use interface for arranging nodes and labels.
RedNotebook is a desktop journal for writing and organizing daily entries. It keeps everything offline on your own device, with tools to format, tag, and search your entries and to add pictures and links.
Mindolph is open source personal knowledge management software for desktop use. It keeps files in separate local workspaces, so knowledge stays in your own storage instead of a cloud service. Files are organized as a tree, and multiple tabs let you switch between open documents.
