My daily driver. This app has a lot to like and is development is rolling along at an encouraging clip. Logseq is an outliner at heart, but with a fluid enough user experience (based on markdown and/or org files) to make it a comfortable option for editing documents. Has a decent selection of plugins that looks like it will continue to expand. Still, there are plenty of rough patches to smooth out in terms of customization and user experience (see this post: https://discuss.logseq.com/t/thoughts-on-logseq-vs-obsidian/8614). This is probably the favorite to meet my goals in the future.

Is it open source? Yes Is it offline-capable? Yes Can blocks/notes exist in multiple locations? Almost. Through the block embed feature, Logseq allows you to transclude blocks in multiple locations. Transclusions can be edited in place, which is a big advantage over other programs that allow embeds/transclusion. But the block only has one "true" parent block, so functionality is limited.

Organization: 4 UX: 3.5 Privacy: 5

A powerful markdown editor with a large user base and a lot of great plugins. It isn't open source but can be configured so as to ensure data integrity. Mobile app is surprisingly good, a rarity among entries on this list. Honestly if this app had a better system for block embeds and editable transclusion, it would probably be my go-to.

Is it open source? No Is it offline-capable? Yes Can blocks/notes exist in multiple locations? No. Pages and blocks can be embedded/transcluded, but transclusions can't be edited in place. There are some clunky semi-workarounds for this but I didn't find them to be practical.

Organization: 3.5 UX: 4.5 Privacy: 5

My heart is with this one. It is still in alpha but the developers' vision is strongly in line with what I'd like to see from an ideal PKM tool. Very flexible layout and block/object based organizational structure. I am an alpha tester and I can attest that this app is still missing a lot of functionality, but you can see that it has huge potential. The verdict is still out, but if Anytype can deliver what it promises it will blow away the competition.

Is it open source? Not yet, but devs say it will be Is it offline-capable? Yes Can blocks/notes exist in multiple locations? Yes

Organization: TBD UX: TBD Privacy: TBD

After failing to include Remnote at all in the initial version of this list, I am adding it directly to the "Frontrunners" section. What gives?? I discovered Remnote shortly after creating this list, and though a lot of its core functionality was impressive, it had a lot of kinks to be worked out. Frustrated by finding yet another app that just didn't quite live up to its potential, I didn't bother to add it here. Now, having revisited Remnote several months later, I am pleasantly surprised by the steady stream of improvements the Remnote team has been adding, making for a much improved experience and a promising future. Highlights include:

• Strong offline functionality, desktop app, and free plan make trying this app as a daily driver relatively painless (and easier to trust with your data despite being closed source)
• Android app available (haven't tried it) and iOS app scheduled for release in February 2023
• Solid plugin system with small but growing list of user-created plugins

Stay tuned! This one could be the app to beat.

Is it open source? No Is it offline-capable? Yes Can blocks/notes exist in multiple locations? Yes

Organization: 4 UX: 4 Privacy: 4.5

Trillium gets a lot right in that it is a good outliner and a good note-taking app, and it has a robust system for allowing notes to exist in multiple locations. Those traits alone make it a solid contender. However it seems to lack a decent plugin system, something that gives options like Logseq, Obsidian and TiddlyWiki much-needed additional functionality and allows users to easily benefit from each other's ideas. There is a script API (actually two APIs), but they are still "experimental" and regardless there's no sign of any sort of centralized collection of user-created scripts.

If this had a working plugin system and an offline-capable mobile version, I'd say it would be better than Logseq and Obsidian. Unfortunately there's no sign that those features are going to be added any time soon though, if at all.

Is it open source? Yes Is it offline-capable? Yes (desktop only) Can blocks/notes exist in multiple locations? Yes (through the "cloning" feature)

Organization: 4.5 UX: 3.5 Privacy: 5

TiddlyWiki is based on a great concept: all components of TiddlyWiki (both notes and the underlying building blocks) are blocks called "Tiddlers" that form a single HTML file that can modify itself. This makes it a lightweight note-taking app that is portable and infinitely customizable. There is a wide selection of plugins, although the degree of quality varies and some may not work well with others. In practice, the notes you create as a user tend to be longer than they should given TW's focus on atomization (there is a promising plugin called Streams that addresses this). Overall, it feels like a strong foundation that someone could build a truly outstanding tool with, but the baseline experience is clunky if you aren't prepared to take some serious time customizing things.

Is it open source? Yes Is it offline-capable? Yes Can blocks/notes exist in multiple locations? Not exactly. Tiddlers can be transcluded but transclusions can't be edited in place. There might be some way to hack together a slick editable transclusion method but I haven't found one.

Organization: 4 UX: 3 Privacy: 5

I really like the functionality and feel of Notion. I don't like that your data is stored remotely by a for-profit company. Pretty much as simple as that. Notion isn't really a contender for me because they'll never change their business model, I just put it here because I really like using it. Note that Anytype is sometimes described as an aspiring Notion clone.

Is it open source? No Is it offline-capable? No Can blocks/notes exist in multiple locations? Yes (through the "synced blocks" feature)

Organization: 4.5 UX: 4.5 Privacy: 1

I've actually never tried Roam Research, but it's hard not to learn about from how much people talk about it. Frankly, if you are willing to shell out $15/month and don't mind the privacy concerns, try this out. I would, except that both are dealbreakers for me. Maybe soon Logseq will be as good.

[Update: I finally tried signing up for a free trial of Roam. If there's something that sets Roam apart from Logseq, I sure didn't notice it. Seems Logseq has done a great job of replicating] Roam's key features. As it stands currently I see no reason to let my free trial roll over to a full Roam subscription.]

Is it open source? No Is it offline-capable? Yes Can blocks/notes exist in multiple locations? Yes

Organization: 4.5 UX: ??? Privacy: 2

This program has a really strong implementation of what they call clones (allowing a node to exist in multiple places). It's a shame that it is an immense pain to set up and to use. Limited selection of plugins and it doesn't look like the developer/community have much interest in making it easier for novices. If you are a serious programmer and have more patience than I do, you might find this to be a really neat tool for coding. Maybe you can find a way to tap into Leo's powerful outlining functionality from a more user-friendly app (the website has a decent explanation of how to use Leo with other programs). I don't know. This one frustrates me because it could be great but the UX is just not there.

Is it open source? Yes Is it offline-capable? Yes Can blocks/notes exist in multiple locations? Yes

Organization: 5 UX: 1.5 Privacy: 5

A powerful organizational tool based on the Emacs text editor. I tried for a while to get into Emacs and concluded that while it is a neat text editor that I continue to use sometimes, I don't have the time to customize it to the point where it I think it would be useful to me as far as PKM is concerned. If you're an Emacs person, you probably already know and love Org and maybe could benefit from combining it with other Emacs packages like org-transclude (pretty underwhelming when I tried it) or Hyperbole. If you're not an Emacs person, be prepared to fully embrace learning how to navigate the Emacs environment if you want this to be your go-to.

Pretty self explanatory: a TiddlyWiki variant trying to replicate the functionality of Roam. Pretty good, but as with many TiddlyWiki-based tools it is kind of rough and doesn't always play nice with other TiddlyWiki plugins. Wasn't for me but this is one I encourage people to try out.

An attempt to replicate Roam using org-mode. Again, if you're an Emacs user, worth checking out, if not, maybe not. If Roam is all it's cracked up to be, this didn't succeed in fully implementing its functionality.

Kind of old and clunky looking. Strictly hierarchical outline structures so I pretty much lost interest when I learned that.

Worth checking out if you are a fan of pure mind-mappers, not so much if you like text-heavy organization methods.

A great app for basic note-taking but not especially feature-rich when it comes to full-fledged PKM.

Tried it, wasn't for me

Outstanding functionality as an outliner app--including the coveted ability to include blocks in multiple locations--but honestly not much else. Not open source, not offline capable, no plugins, and no sign that any of that will change. If you just want a straightforward outliner tool Workflowy does the job well but for a more complete PKM system there's nothing this app can do that couldn't be done just as well by Remnote (and a lot Remnote can do that this can't).

Billed as an open source Evernote alternative. Thanks @candroid_man for suggesting this one.

Don't know much about this one, but of course I have been seeing a lot about it because they are spending a ton on advertising. They are clearly targeting users in the business realm but it looks like it has a ton of features and would probably be a great option if it weren't for what I'm sure are glaring privacy concerns (despite their toothless assertion that they are "serious about security and privacy." I honestly have been meaning to sign up (with a throwaway email of course) and check this one out, but the lack of personal control over your data makes it hard for me to imagine sticking around.

Absolutely no idea if this one is legit.

Seems to me very similar to Logseq, but less feature-rich.

[Update: Athens Research has been discontinued]