Are you looking for a note-taking app, but do you want it to be open-source? You have probably tried all kinds of the best note-taking apps but wish to make changes and find a more secure place for all your notes and ideas. Not just in the editing the theme way but completely changing the code. That's when open-source software comes into play.
You can download note-taking apps that offer their code to the public so you can make changes, share with others, and create apps that work exactly how you want. Plus, if you are a programmer or developer, the idea of changing and modifying apps sounds like a dream, and it's real.
Here's the thing: most popular note apps lock you into their ecosystem. Proprietary software means you're stuck with whatever features they decide to build, and if they shut down tomorrow, your data could vanish. Open-source flips this entirely. You own your data, you can inspect every line of code to verify security, and if something bugs you (literally or figuratively), you can fix it yourself or wait for the community to do it.
In 2026, open-source note-taking apps have matured significantly. They're no longer the clunky, developer-only tools they used to be. Many now rival (and in some cases surpass) commercial apps in terms of features, design, and user experience. The trade-off? You might need to spend a few minutes setting things up, but honestly, the freedom is worth it.
What is Open Source Note-Taking Software?
Open-source note-taking software allows you to take, organize, and customize how your notes are stored. Open-source tools appeal to programmers, students learning to code, and those who want to build or contribute to applications. It also allows apps to evolve thanks to those contributing, helping them grow in popularity and usage.
Think of it this way: when you use a closed-source app like Apple Notes or Evernote, you're trusting that company with your data. You can't verify their encryption claims, you can't see how they store your information, and you definitely can't modify the app to suit your workflow better.
With open-source apps, the code is public on platforms like GitHub. Anyone can review it, audit the security, and contribute improvements. This transparency builds trust, and it also means bugs get fixed faster because you have thousands of eyes on the code instead of just one company's development team.
Beyond security and customization, open-source note apps often support data portability better than commercial alternatives. Your notes are usually stored in standard formats like Markdown or plain text, making it easy to migrate between apps or back them up independently. No vendor lock-in, no proprietary formats that only work with one app.
1. Joplin
Popular with Developers
Joplin is an open-source notes app that supports to-do lists; it has a minimal interface and is easy to navigate. You can create and organize notes into notebooks using multiple text editors such as Rich Text and Markdown. It's also an "offline-first" app and is open source.
Your data will always be saved and accessible via your device, even without a connection. You can then access your notes on the go and save them to your device. Your notes are then secure using end-end encryption and synced into the Joplin Cloud or another Cloud such as Dropbox and Onedrive. You won't have to worry about anyone reading your notes or stealing them.
It allows you to customize the app using open source through custom themes and plugins; this is great for developers or students to learn how coding works. You can create your own plugins and code scripts using the extension API.
Joplin is a fan favorite for many of the open-source community thanks to being on the market for some time and the ability to connect to other services. This is one of the more common options, as it has staple abilities for note-taking.
What really stands out is the plugin ecosystem. There are hundreds of community-built plugins that add everything from advanced search to kanban boards to graph views of your notes. Want to embed YouTube videos directly in your notes? There's a plugin. Need to sync with WebDAV instead of cloud services? That works too.
The offline-first approach is clutch for anyone who travels frequently or works in areas with spotty internet. Your notes sync when you reconnect, but you never lose access to your data. Compare that to web-only apps that leave you stranded without WiFi.
One thing to note: Joplin's interface isn't the prettiest compared to newer apps like Anytype or Obsidian. It's functional and clean, but if aesthetics matter to you, it might feel a bit dated. That said, themes can help, and the functionality more than makes up for it.
2. Anytype
Is Anytype good for me?
Anytype is a note-taking app where you can create pretty much anything. Thanks to its open-source nature and flexible use, you can create a knowledge base, a journal, a habit tracker, and more. It is also a super secure application using only local on-device encryption. Only you can access your notes unless you decide to share Peer to Peer.
Sharing with peers means you can edit and share files without needing authority or a central server. Open code with it means you can analyze, compile, and run software components on your device without having to depend on anything else. You can also open protocols to build apps inside Anytype without permission.
Anytype is probably the most accessible open-source notes app because it uses no-code editing, which means you can edit your notes and workflow how you like. You don't need to understand code to create apps and customize your workspace.
The power of Anytype comes from the abilities that make it similar to Notion, allowing you to bring ideas together, connect them, and even bring them to life in a graph (which Notion hasn't done yet).
What sets Anytype apart is its philosophy around data sovereignty. Your data lives on your device, encrypted by default, and you control who sees it through peer-to-peer sharing. This is a big deal if you're concerned about cloud providers snooping on your notes or getting hacked. No central server means no single point of failure.
The interface is gorgeous, honestly one of the best-looking open-source apps out there. It feels polished and modern, with smooth animations and thoughtful design. If you've bounced off other open-source tools because they looked like they were built in 2005, Anytype will surprise you.
The graph view is stupidly good for connecting ideas. If you're building a second brain or working on complex projects with interconnected notes, being able to visualize those connections helps tremendously. Notion users have been begging for this feature for years, Anytype just ships with it.
One caveat: Anytype is still in beta as of late 2026. It's stable enough for daily use (I've been using it for months), but expect the occasional bug or missing feature. The development team is active and responsive, though, so issues get addressed quickly.
3. Simplenote
Should I Use Simplenote?
Simplenote is an open-source note-taking app with Markdown support for writing, previewing, and publishing notes. It's also free to use, although you can pay to support the app and its development. Notes are constantly updated in real-time on all devices without the need to sync or save. This saves users a ton of time, and you don't have to worry about accessing notes.
Your notes are backed up every time you edit so that you can re-visit past versions. Now that Simplenote is open source, users can contribute to changes, edit the app, and create their own edited code from the source code inside each device. This means you can customize Simplenote however you want and share with others.
Simplenote runs on Simperium, a syncing platform built specifically for this kind of real-time collaboration. We won't go into detail, but this is basically what stores and syncs notes across apps, and it handles all the work for you. Most apps have their version of this with their names.
Simplenote is owned by Automattic, the creator of WordPress, and offers an extensive free experience for managing your notes without limits and shared abilities for people who want a balance between intense-looking note apps and an approachable feel.
The simplicity is the selling point here. There are no databases, no fancy graph views, no AI features. Just notes, tags, and search. If you've ever felt overwhelmed by apps that try to do everything (looking at you, Notion), Simplenote is refreshingly minimal.
Version history is a lifesaver. I've accidentally deleted entire paragraphs before and being able to restore from a previous version saved me hours of rewriting. Every edit creates a snapshot, so you can roll back to any point in time.
The cross-platform support is solid: Windows, Mac, Linux, iOS, Android, and web. Syncing happens instantly in the background, which is rare for open-source apps. Most require manual syncing or third-party services, but Simplenote just works.
Downside? The lack of features might be too limiting for power users. No folder hierarchies (just tags), no rich media embedding, no tables or databases. It's purely text-focused. If you need more than that, look at Joplin or Anytype instead.
4. Standard Notes
Standard Notes might be the most secure note-taking app with open source. You can make sure your notes are encrypted, and only you can read them. Everyone can use the public open-source code to edit and make changes. You can store everything inside Standard Notes, from notes to files, meaning you don't need to use other apps and risk data being breached.
This makes the experience much more productive, as you are all in one space. Notes can also be written with markdown, rich and simple text. You can create spreadsheets and to-do lists and manage your tasks. The whole app is very minimal and easy to use.
In terms of why this is the most secure notes app, you can choose to have nightly email backups that send a copy of your data; you can also set up two-factor authentication and even see long-term revisions of older notes. Proton now owns Standard Notes, the creators of Proton Mail.
The security focus is no joke. Standard Notes uses XChaCha20-Poly1305 encryption, which is military-grade stuff. Your notes are encrypted on your device before they ever reach their servers, so even if Standard Notes got hacked, attackers would only see encrypted gibberish.
Being owned by Proton is reassuring. They have a proven track record with secure email and VPN services, and they've committed to keeping Standard Notes free and open-source. This acquisition actually made the app better, with more resources for development.
The editors are interesting: you can switch between plain text, Markdown, rich text, code, or even a spreadsheet editor. Each note can use a different editor, which is flexible. Some of the advanced editors (like the code editor with syntax highlighting) require a paid subscription, though.
Nightly email backups are a nice touch. Every night, you get an encrypted backup sent to your email. If your account gets compromised or you lose access, you still have your data. Most apps don't offer this level of backup redundancy.
That said, the free tier is pretty limited. You get one editor type and basic features. For the full experience with themes, multiple editors, and advanced features, you need the paid plan at around $9.99/month. Not crazy expensive, but Simplenote and Joplin offer more for free.
Standard Notes is a secure E2E note-taking application with a simple markdown nature.
5. Notesnook
Is Notesnook Right For Me?
Notesnook is another super secure and private note-taking app with open-source software. Notesnook is end-end encrypted and allows you to create encrypted monographs of your notes, meaning no one else can read them. It allows you to create any notes you want using basic formatting, markdown support, code blocks, and more, then organize them into notebooks.
Everything will also seamlessly sync across your devices. All client apps are now open-sourced on GitHub. This means you can use the importer, web clipper, and sync server to create your code and modify how you use the app. This also means the code will always be available, even if the app closes. A handy little feature with Notesnook is its reminder feature.
You can now keep track of your tasks and reminders inside Notesnook, making this a multipurpose app that is super productive. Notesnook is growing as a popular tool for managing notes using open source. Many people like the combination of security with reasonable pricing; the yearly pricing makes the Pro experience with more security functions even more approachable.
What I really appreciate about Notesnook is how it doesn't compromise on design while prioritizing security. The interface is clean and modern, with thoughtful touches like color-coded notebooks and a distraction-free writing mode. Too many secure apps look like they were designed by cryptographers (because they were), but Notesnook actually feels pleasant to use daily.
The web clipper is surprisingly good. You can save entire articles from the web, strip out ads and formatting, and store them as searchable notes. Perfect for research or saving articles to read later without relying on Pocket or Instapaper.
Encrypted vault feature is clever: you can lock specific notes behind an additional password. So even if someone gets access to your unlocked app, your most sensitive notes stay protected. Good for storing passwords, personal documents, or anything you really want to keep private.
The free tier is functional but limited: 50MB storage and 5 attachments. For serious use, you need Pro at $4.99/month (or $49.99/year, which is a better deal). That's cheaper than Standard Notes and gives you unlimited storage, unlimited attachments, and encrypted backups.
Migration tools are excellent. They have importers for Evernote, Simplenote, Google Keep, and even plain Markdown files. Makes switching less painful than most apps.
6. AFFiNE
Is Affine right for me?
AFFiNE Pro is an all-in-one notes app that allows you to write, draw, and plan tasks and projects. You can use the whiteboard to brainstorm, add databases, tables, and more. It is a hyperfused platform as it allows you to consolidate your entire workflow in one place, meaning you no longer need to switch between apps.
You can do everything in one place. You can collaborate with teams, plan projects, track progress, and link databases. Inside whiteboards, you can add videos, draw, add lists, and use AFFiNE Copilot AI to ask questions to support content. It also uses open-source code accessible to the public so you can contribute and enhance the app for yourself and others.
You can open issues inside the community and engage with others using the app. AFFiNE is in its early days, but the powers are very interesting. Combining document management and whiteboard allows you to be creative and turn anything into a visual whiteboard, much like if Evernote and Miro had a baby. One that could be very interesting.
The ability to switch seamlessly between document mode and whiteboard mode is game-changing. Start writing a note, realize you need to visualize something, and boom - same content, different view. No copying and pasting between apps, no losing context. This is exactly what creative work needs.
AI Copilot integration is ambitious. You can highlight text and ask questions, generate summaries, or get writing suggestions. It's powered by your choice of AI models, which is cool because you're not locked into one provider. That said, it's still early and can be hit or miss depending on what you ask.
The database functionality is surprisingly robust for an open-source app. You can create linked databases, add properties, filter and sort - basically Notion-style database blocks. Combined with the whiteboard, you can visualize your database as a kanban board or mind map.
Being in early development means rough edges. Syncing can be slow sometimes, and there are occasional bugs. I've had the app crash twice in the last month, which is annoying but not a dealbreaker given how much potential it has.
The community on GitHub is super active. Feature requests get discussed openly, bugs get fixed quickly, and you can actually influence the roadmap. That level of transparency and community involvement is rare, even in open-source projects.
How to Choose the Right Open-Source Note App
Decision Guide
Picking the right open-source note-taking app depends on what matters most to you. Let's break this down by priority.
If security is your top concern, go with Standard Notes or Notesnook. Both use end-to-end encryption and have been audited by security researchers. Standard Notes has Proton backing it, while Notesnook offers better value with its annual pricing. Can't really go wrong with either.
For developers and power users who want maximum customization, Joplin is the clear winner. The plugin ecosystem is massive, it supports multiple sync methods, and the code is mature and well-maintained. You can bend it to do basically anything you need.
If you want something that just works without fuss, Simplenote is your answer. No complex setup, no decisions about sync methods or encryption schemes. Install it, start typing, done. The cross-platform sync is rock solid, and being owned by Automattic means it's not going anywhere.
Visual thinkers and people building knowledge bases should look at Anytype or AFFiNE. Anytype has the better polish and stability right now, while AFFiNE offers unique whiteboard capabilities if that's your thing. Both are early in development but show incredible potential.
Budget matters too. Simplenote and Joplin are completely free with no restrictions. Notesnook has a generous free tier and affordable paid plans. Standard Notes and Anytype lock important features behind subscriptions, which is fine if you need what they offer, but frustrating if you just want basic note-taking.
Don't overthink this. Most of these apps support standard export formats like Markdown, so switching later isn't painful. Pick one that feels right, use it for a month, and adjust if needed. The beauty of open-source is you're never truly locked in.
Why Choose Open-Source Note Apps?
The Case for Open Source
Look, we get it. There are dozens of polished, commercial note-taking apps out there. Why bother with open-source?
Longevity is a big one. Commercial apps shut down all the time. Remember Google Keep alternatives that disappeared? Or Evernote's decline? With open-source, even if the original developers abandon a project, the community can fork it and keep it alive. Your data and the tools to access it will always exist.
Privacy can't be verified in closed-source apps. They can claim anything about encryption and security, but you're taking their word for it. Open-source code can be audited by anyone. Security researchers regularly review these apps, and vulnerabilities get found and fixed publicly.
Community development often moves faster than corporate development. Joplin has added more features in the last year than Evernote has in five. When thousands of developers can contribute, innovation happens quickly. Plus, you get features users actually want, not what some product manager thinks will increase engagement metrics.
No rug pulls. You know how commercial apps suddenly change pricing, remove features, or pivot their business model? Can't happen with open-source. The code is yours. If you don't like the direction a project is going, fork it or switch to an alternative that uses the same file format.
The trade-off is usually polish and user experience. Commercial apps often have slicker interfaces and better onboarding. But honestly? That gap is closing fast. Anytype and Notesnook look as good as any commercial app, and they respect your privacy while doing it.
Other note-taking apps to consider
These might not have open-source abilities but are considerations if you're exploring options beyond the open-source ecosystem. Apps like Obsidian (source-available but not fully open-source), Notion (closed-source but popular), and Logseq (open-source graph-based notes) all have their place depending on your needs.
