Tool Review: Hypothesis

Screenshot of Hypothesis showing example annotations of Act 1 Scene 1 of Hamlet.

In my role as Digital Humanities Librarian, I manage a monthly DH newsletter for faculty on campus to share readings, events, and other DH items. In the newsletter I highlight one DH tool each month, creating a sample project and sharing my thoughts. To keep the emails short, my full thoughts will be posted here under the Tool Reviews category.


Hypothesis is an open source web-annotation tool that allows users to annotate webpages, PDFs, and other online documents either privately, in groups, or publicly. It is currently operated by anno and in August 2022 ITHAKA invested in the tool. As of September 2022 Hypothesis had been used to generate over 40 million annotations

Rather than a tool to be used for the creation of digital projects, Hypothesis is primarily a digital pedagogy tool. It allows for social reading of texts. For example you could have your students read and annotate one of their assigned readings in a private Hypothesis group for your class, which would allow them to reply to each other’s annotations, and learn from each other and be in conversation with one another outside of class. 


These annotations function as digital marginalia and users can highlight or comment on sections of the text, as well as reply to other comments. This means users can also link to related content creating a richer reading experience, especially if readers post questions or reply to questions with more contextual or background information. 

As mentioned, these annotations need not be visible to the public. They could be private annotations if readers want a better way to mark up their readings digitally, or it can be done in private groups, so only other members of the group can see them. 

I imagine that most people will use Hypothesis through the browser extension, which allows users to “turn on” annotations for any webpage they are on. Once the extension is activated it is easy to select which group you want to annotate within. Then you can highlight, comment, and reply to your heart’s content. You simply select the text you are interested in and select whether you are making an annotation or a highlight and then keep on reading. By clicking on portions of the text that are already highlighted you can see other people’s annotations in the sidebar, and in that same area you can reply to annotations.  

It is also possible to integrate Hypothesis into your institution’s LMS, although that is a larger project that would require your institution’s IT/education technology/etc. department to be involved. I stand corrected! They have integration for all of the major LMSs, which will also automatically make a group for your class.


Honestly, I think this tool would be useful for any class that has assigned readings, which is to say all classes. It creates more asynchronous opportunities for the class to learn together outside of the classroom, and a more intuitive way of having conversations with their peers about readings than forum posts. While I think this is appropriate for all student levels, this Liquid Margins episode (embedded below) discusses how particularly useful it is in first year seminar courses. 

This post from the Hypothesis blog on 10 Ways to Annotate With Students provides some great inspiration for teachers looking to integrate social annotating to their curricula. In particular I think the first point about seeding a document with a few starter annotations is important to keep in mind, especially the first few times you are introducing this type of assignment. Speaking from experience, I used Hypothesis for a course in grad school, it is intimidating to make the first few annotations. Even more so when you aren’t sure what sort of annotations you should be making. It could also be worth sharing the Annotation Tips for Students resource Hypothesis has made to help give students ideas of what makes a useful annotation. 

One specific way I think it can be useful is for having students annotate/comment on the class syllabus. There have been many conversations, especially on Twitter, on what is gained by having students annotate their syllabuses and although those examples are using Google Docs for the annotations, I think Hypothesis would be another good tool for that sort of interaction.  


I think the main limitation for this tool is that it requires some time to get it set up at the start. If you want your class to be commenting in a class-specific group, and not publicly for example, you need to create the group and make sure all of your students make accounts and get added to the group. Then you need to make sure they know how to make sure they are posting to the correct group so that their classmates can see their contributions. Apart from that, as long as you are annotating publicly available text-based content I don’t think there are many limitations. 

Again, see my note above about the LMS integration. If you use a major LMS it will be easy to get your class up and running with Hypothesis.

And one of the strongest affordances is how it allows students to thread conversations in the text they are discussing, and not asking them to read something and then have a conversation on a class forum hosted elsewhere. By keeping the conversation in the document itself it can help tie what is being discussed directly to the text.


Now, as the Twitter conversations I linked to earlier mention, Google Docs’s commenting feature can function in almost the exact same ways as Hypothesis. The advantage of Google Docs is that the feature is native to the platform and doesn’t require users to download extensions or create new accounts, but it only works for Google Docs whereas Hypothesis could be used for any publicly available web page. But if you want students to annotate your class syllabus or assignment pages and they already are Google Docs, then it may make more sense to just use the commenting feature in the tool. 

There is another social annotation tool out there, Perusall. And while it is also free, it seems that the main additional feature is that it allows students to purchase textbooks within their platform which can then be socially annotated, while also allowing students to other types of web content like articles and webpages.  


Kalir, Jeremiah H. “Designing a Social Learning Analytics Tool for Open Annotation and Collaborative Learning.” In Learning Analytics in Open and Distributed Learning: Potential and Challenges, edited by Paul Prinsloo, Sharon Slade, and Mohammad Khalil, 77–89. SpringerBriefs in Education. Singapore: Springer Nature, 2022.

———. “Open Web Annotation as Collaborative Learning.” First Monday, June 1, 2019.

———. “Social Annotation Enabling Collaboration for Open Learning.” Distance Education 41, no. 2 (April 2, 2020): 245–60.

Kalir, Jeremiah Holden, Esteban Morales, Alice Fleerackers, and Juan Pablo Alperin. “‘When I Saw My Peers Annotating’: Student Perceptions of Social Annotation for Learning in Multiple Courses.” Information and Learning Sciences 121, no. 3/4 (January 1, 2020): 207–30.

Wranovix, Matthew, and Mary Isbell. “The Digital Common Read: Creating a Space for Authentic Engagement with Social Annotation.” Journal of the European Honors Council 4, no. 1 (June 30, 2020): 1–10.

Zucker, Lauren, Jeremiah Kalir, Michelle Sprouse, and Jeremy Dean. “Foregrounding the Margins: A Dialogue about Literacy, Learning, and Social Annotation.” Teaching/Writing: The Journal of Writing Teacher Education 10, no. 1 (March 24, 2021).

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