I’ve been playing with Hook, an app I’ve started hearing about. It’s an interesting bird, and its own docs didn’t explain why I should want to use it. That’s too bad, because after downloading it and playing around for a few days, I understand why people are excited about Hook.

Let me try my own explanation:

Hook knows how to talk to a lot of other apps (about 150 as of now) and ask or direct them to do a few things:

  • Get the ID of the active item in the app, like the omnifocus:///task/... link of the selected item in OmniFocus.
  • Open the item in the app with a given ID.
  • Get the name of the active item in the app, like the title of the front tab in Safari.
  • Create a new item in the app.

Those first 2 options are interesting because many of its supported apps don’t offer their own URL scheme. You can refer to a web page by its address or an OmniFocus object by its URL as seen above, but Apple’s own Notes app doesn’t offer a way to make a link to a specific note. Hook solves this by offering its own URL scheme. For instance, if I try to open the URL hook://notes/dt/1498065293 on my Mac, it opens the Hook app, which sees that it’s supposed to open the Notes app, and uses AppleScript or JavaScript wizardry to go straight to the desired note. Or consider emails, each with their own unique Message-ID. Hook accepts URLs like hook://email/[Message-ID] and opens them in your favorite mail app, even if you’ve moved the mail to a different folder or switch mail apps since you copied the link.

That’s slick, and if Hook only allowed me to deep link straight into Mail and Notes and Finder and iTerm (!!!) and VS Code (now you’re showing off), it would be invaluable.

The “a-ha!” moment was understanding that Hook itself stores links between objects, even if they’re not editable. For example, suppose you’re viewing a PDF and it reminds you of a web page. You can ask Hook to copy the PDF’s location in Finder. When you open the web page in Safari, you can use Hook’s “Hook to Copied Link” action to make a two-way link (the eponymous “hook”) between the PDF and the web page. That is, if you come back to that web page a week later and wonder what PDF it reminds you of, you can press the Hook shortcut and it will pop up a list of all documents “hooked” to that web page. Use the arrow keys to scroll down to the PDF and press enter, then voila!, it opens the PDF for you.

This is the magic in Hook: you can make linkages between resources that aren’t under your own control. You don’t download a webpage and then edit its metadata to link to the PDF. Hook says “oh, when you’re looking at this page, I’ll remember that it made you interested in this PDF”. And even if that PDF can’t be edited to add a link to the webpage, Hook manages that association for you.

In this sense, Hook is like a personal wiki, except that you don’t have to edit a page to associate bits of data and that doesn’t have to be in the same app. You open the first item and press a few keys, then open the second item and press a few more, and now your system knows that you think these 2 items are related and can remind you of that later. That’s powerful. It’s easy enough to make a link from a Things action to its information resources in DEVONthink. Linking from DEVONthink information back to Things so that you can bounce right back to your project planning without lifting your hands from the keyboard? That’s harder, and it’s the true value of Hook.

A note on terminology: giving things a good name is hard, but I might’ve called “Hook to Copied Link” almost anything else. My mind kept reading “Hook” as a noun, as though I were converting it to a “Copied Link” similar to calling “JPEG to PNG” in a graphics program. Instead it’s a verb: “create a link back to the item whose link is in the clipboard” is clearer to me, although too verbose.

Hook is available in a free version that’s focused on opening links, not making them. The idea is that you can send your coworker a link to a file stored in Git or Dropbox, or an email they were Cc’ed on, and they can go straight to it. That’s nifty, but in practice I can’t imagine my friends tolerating this: “hey Tom, I’m going to send you a link, and you’ll need to download this free app from…” “Stop right there.” Hook is cool and I’ve told several friends about it, but I’m not kidding myself about the likelihood of them all installing it.

Maybe I’ll look back on this in a few years and laugh at my own skepticism because it became the universal standard app that everyone uses, but I’m not counting on it.


CogSci, Hook’s authors, have an interesting licensing model: if you buy the “essentials” or “pro” version, you can use any new versions that come out within 12 months of your purchase date for free, forever. If newer versions come out with features you can’t live without, you can buy a discounted renewal license that’s good for another 12 months of updates.

I love this idea. I hate renting software, and this is a nice compromise between an unsustainable “buy it once and get free support for the rest of your life” and “keeps working as long as you keep paying”. I wish this licensing model were the norm.


The few things I dislike about Hook are minor:

  1. It’s not available for iPhone and iPad. I’m not sure how an iOS version of Hook would work (perhaps through the Share action? Through drag and drop?), but I wish it were on my favorite mobile platforms. I’m using my iPad for a lot of work I’d would have used my Mac for before and cross-platform tools are splendid. An mobile “Hook Lite” version that supported opening hook:// links would help a lot.
  2. I haven’t met another person using it. Although I’ve read articles about Hook, I’m the only person among my friends, family, and coworkers who has it installed. The link sharing idea could be brilliant if it becomes ubiquitous but I don’t want to be its lone evangelist among the people I know, many of whom are still annoyed by my Emacs and Amiga days.
  3. CogSci: please ask someone who doesn’t work with you to review your home page. All the information there is technically accurate, but much of it only becomes clear to users who’ve downloaded Hook and experimented with it. If I hadn’t been evaluating the app on the recommendation of a friend, I might not have downloaded it. Your app is cool. Give it some marketing love!

Summary: try it.

I like Hook. I haven’t registered it yet but I’m leaning that way. Again, if Hook only allowed me to create deep links into apps that don’t natively support them, that’s enough reason to buy it. I’m not sold on the life-changingness of the bidirectional links between documents — not because I don’t think it’s an wonderful idea, but because I’m a sucker for things that promise to be the cure for what ails ya and then become disillusioned when they’re not as amazing as I’d hoped. For example, I’d heard that Zettlekasten note keeping is the magic key to life-long productivity, but realized that it’s a nice solution to problems I don’t have. I’m being cautious about Hook for the same reason. But skepticism aside, I think its core conceit that making links between all your related resources is valuable has merit, and Hook makes this easy. I’m still in the trial period my wish is it’s as helpful as CogSci thinks it will be.

Try Hook. I think we’re going to like it.