Open Source Note Taking Apps
Notes are the longest-lived data most people have - years of ideas, research, and plans - which makes the storage format matter more than the editor. The open source apps below keep notes in formats you can read without the app that made them, mostly Markdown and plain files, and the ones that sync can do it through a server you run yourself instead of someone else's cloud.
AppFlowy
Open source AI workspace for projects, wikis, and teams with self-hosting and data control
AFFiNE
Local-first open-source workspace that merges docs, whiteboards, tables, and AI as a Notion and Miro alternative
Memos
Self-hosted Markdown note-taking timeline for quick notes, daily logs, links, and snippets
Joplin
Offline-first Markdown note and to-do app with encrypted sync across desktop and mobile
SiYuan
Privacy-first personal knowledge management with Markdown WYSIWYG, block references, and Docker hosting
Logseq
Privacy-first knowledge base for graph notes, Markdown, Org-mode, PDF annotation, and tasks
Outline
Team knowledge base and wiki with realtime collaboration, Markdown compatibility, and self-hosting documentation
Trilium Notes
Hierarchical note-taking app for large personal knowledge bases, with local use and self-hosted sync
Open Notebook
Open source, privacy-focused alternative to NotebookLM with local deployment and multi-model AI support
Our picks
Which one fits depends on whether you keep private notes, a linked knowledge base, or a shared team wiki.
Encrypted personal notes across devices: Joplin Joplin keeps Markdown notes in notebooks that stay on your device and work fully offline, then syncs them with end-to-end encryption through Nextcloud, Dropbox, OneDrive, or its own service. It imports Evernote exports while preserving images and attachments, and the Firefox and Chrome web clipper saves pages straight into your notes.
Linked graph knowledge base: Logseq Logseq organizes notes as a connected graph on top of plain Markdown and Org-mode files, so ideas link and resurface instead of sitting in folders. It adds PDF annotation and task management, and plugins and themes let you reshape the workflow around how you think.
Large hierarchical knowledge base: Trilium Notes Trilium arranges notes in an arbitrarily deep tree and lets a single note appear in several places through cloning, which suits a knowledge base that grows past a hundred thousand notes. It runs locally or against a self-hosted sync server under Docker, with a WYSIWYG editor, code notes, full-text search, and note versioning.
Team wiki with real-time editing: Outline Outline gives a team one searchable home for documentation, with a fast Markdown editor, slash commands, and simultaneous editing plus comments. Read and write permissions, user groups, and public links control access, and the same codebase runs on the hosted service or a server you manage with Docker.
How to choose an open source note app
Look at the storage format first, because it decides whether your notes survive the app. Plain text and Markdown files in a normal folder are the safest bet: they open in any editor, sync through any file tool, and will still be readable in a decade. Apps that store notes in a proprietary database or a single binary blob are more fragile, so if you pick one, make sure it has a clean, complete export.
Next, decide how syncing should work. Some apps treat notes as files and let you sync them through any drive or version-control tool you already trust. Others run an optional server you host, which adds real-time sync, sharing, and end-to-end encryption without handing your notes to a vendor. If you mostly work on one machine, a local-only app with periodic backups is the simplest setup of all.
Then match the editing model to how you actually think. Outliners reward people who work in nested bullets; document editors suit longer prose; and link-first apps that connect notes into a graph reward dense, interconnected knowledge bases. Check the practical details too - attachment handling, full-text search, mobile apps, and whether it can import the notebooks you already have so the switch is a copy rather than a rescue.
Related categories
Frequently asked questions
Will my notes be locked into the app?+
That is the main reason to choose from this list. The apps here favor open formats - usually Markdown or plain text in ordinary files - so your notes are portable by default and readable without the original app. Even the ones that use a database provide a full export. The rule of thumb: before you trust an app with years of notes, confirm you can get everything back out in a standard format.
Can I sync notes across devices without a cloud account?+
Yes. File-based note apps store everything as plain files, so you can sync them with any tool you like - a self-hosted file server, a version-control repository, or a commodity cloud drive - without an account tied to the note app itself. Several apps also offer their own optional server you can host, which adds device sync and end-to-end encryption while keeping the data on hardware you control.
Can I import notes from Evernote, Notion, or OneNote?+
Usually, yes. Because these apps work in open formats, the common path is to export from your current tool (most export to Markdown, HTML, or ENEX) and import the result. Formatting and attachments survive the move better when both sides speak Markdown, so expect to do a little cleanup on heavily formatted pages. The payoff is that the next migration will be far easier, since your notes now live in a portable format.
Do open source note apps work offline?+
Most are offline-first by design: your notes live on your device and are fully editable with no connection, and sync simply reconciles changes when you are back online. This is a direct contrast to cloud-only note services, where losing connectivity can mean losing access to your own writing. If uninterrupted offline access matters to you, favor the file-based apps on this list.