Hypothesis vs MarkLayer: a free Hypothesis alternative
MarkLayer and Hypothesis are both free and open source, but they anchor to different things on a page. Hypothesis anchors to text: select a passage, and the annotation attaches to that exact string, portable across however the page reflows. MarkLayer anchors to space: draw an arrow at a coordinate, pin a comment to a button, and the mark lives on the visual layout itself, not a string of words.
That distinction decides which tool actually fits a given job, more than any feature comparison does. A research group annotating a journal article, a class discussing a shared reading, a journalist marking up a source document: all three are annotating text, and Hypothesis's W3C-standard, publicly addressable layer is built exactly for that, sign-up required, groups persistent across sessions. A designer circling a misaligned button, a QA engineer flagging a broken layout, a PM pointing at a chart that renders wrong on mobile: none of that is text to select, and Hypothesis has no drawing tool or pixel-anchor to reach for it with.
Where the comparison gets genuinely interesting is a page that's both: a data-heavy article, an annotated report, a research tool with real prose alongside its UI. Nothing stops a team from running Hypothesis for the argument and MarkLayer for the interface on the very same URL; they don't compete for the same anchor point, so neither one has to lose for the other to be the right call.
Choose MarkLayer for visual feedback on any webpage. Drawings, arrows, and pinned comments anywhere on the page. Choose Hypothesis if you need a public, W3C-standard text annotation layer for scholarly research, classroom reading groups, or article-level discussion.
On this page
At a glance
| Feature | MarkLayer | Hypothesis |
|---|---|---|
| Price | Free | Free |
| Open source | Yes | Yes |
| Text highlighting + notes | Yes | Yes |
| Drawing & shapes | Yes (freehand, shapes, arrows) | No. Text-only |
| Pinned comments anywhere | Yes. Pin to any pixel | No. Anchored to text selections |
| Real-time live cursors | Yes | No |
| Sign-up required | No | Yes (for sync; anonymous use limited) |
| Public annotation layer | No. Share-by-link only | Yes. W3C standard, public groups |
| Best for | Visual feedback on any webpage | Scholarly text annotation, research, teaching |
About Hypothesis
Hypothesis is an open-source web annotation layer focused on text-based annotation for academia and research.
About MarkLayer
MarkLayer is a free, open-source web app for annotating any live webpage. Paste a URL atmarklayer.app and draw, comment, arrow, or highlight directly on the page in your browser — no install, no account, no sign-up. Share a single link and anyone can open the annotations in any browser. A free Chrome extension is available for the sites the web app cannot embed, such as pages behind a login, but it is optional and never required to view a share link. There is no paywall and no trial period.
Hypothesis is the gold standard for scholarly text annotation. MarkLayer is the visual one, built for when the annotation is an arrow, not a quote. They complement each other; same browser, different workflows.
When to choose MarkLayer
- You need to draw, point at, or visually mark up parts of a page (not just text).
- You want real-time collaboration with live cursors.
- You want zero sign-up.
- You're reviewing UI, design, or visual content rather than scholarly text.
When to choose Hypothesis
- You're annotating academic papers, articles, or text-heavy content.
- You need a public, persistent, W3C-standard annotation layer.
- You're building educational workflows where students annotate readings together.
- You want annotations that persist on the web outside any single share link.
Frequently asked questions
- Are MarkLayer and Hypothesis competitors?
- They overlap on the surface but solve different problems. Hypothesis is built for scholarly text annotation. MarkLayer is built for visual feedback. Drawings, arrows, comments pinned anywhere on a page.
- Can I use both?
- Yes. They don't conflict. You can run Hypothesis for research workflows and MarkLayer for visual UI feedback on the same browser.
- Does MarkLayer support text-based annotation like Hypothesis?
- MarkLayer supports highlighting text with comments, but its primary strength is visual annotation. Drawings, shapes, and arrows on the page itself.
- Is MarkLayer's annotation data public like Hypothesis groups?
- No. MarkLayer annotations are private until you share the link. There is no public annotation layer or open group system.
- Which one should a research team actually install?
- Often both, for different halves of the work. Hypothesis for the literature as a public, standards-based layer: a passage highlighted in a paper, a note, a reading group working through the same PDF over a term. MarkLayer for a working pass on one document or one build: it opens a PDF or an image too, by link or upload, and adds drawing, arrows and pinned comments that a text anchor cannot express, then hands the result to anyone as a link. One is a permanent annotation layer; the other is a review you send.
Related comparisons
Try MarkLayer
Paste any URL at marklayer.app and annotate the live page in your browser. No install, no account, no sign-up. Recipients of your share links don't need to install anything either.
Annotate a page