Hypothesis
Annotate any web page collaboratively. Highlight, comment, and share notes with your team.
What should journalists know about Hypothesis?
Hypothesis adds a transparent annotation layer to any web page or PDF. Install the Chrome/Firefox/Edge extension, highlight a passage, add a note, share it with a group. Annotations follow the W3C Web Annotation standard — Hypothesis helped write that spec in 2017, which means your annotations aren't locked into a proprietary format. The nonprofit/PBC dual structure (501(c)(3) Hypothesis Project + Annotation Unlimited PBC 'Anno') keeps incentives aligned: no ads, no data monetization, grant-funded origins (Sloan, Mellon, Knight). Anno raised a $14M seed in 2022 led by ITHAKA (JSTOR's parent), At.inc, Triage Ventures, Esther Dyson, and Mark Pincus. As of 2025, Hypothesis reports 1M+ users and 300+ institutional customers, mostly in higher ed. Journalism adoption is real but niche — Climate Feedback is the standout example. The 2025 additions (image annotation in PDFs, @mentions, grading tools) are education-focused. If you want collaborative source annotation for an investigation, this is the best open-source option. Just know the product roadmap follows the tuition dollars, not the newsroom.
Collaborative source annotation during investigations. Fact-checking published articles with inline evidence. Editorial teams reviewing web content together. Building annotated reading lists for research. Teaching verification and media literacy.
Heavy PDF-only workflows — image annotation works in PDFs but the tool is browser-first. Annotating content you want to keep completely invisible (public annotations reveal what you're reading). Real-time collaborative editing (this is annotation, not Google Docs). Mobile-first workflows — the desktop extension is far superior to the mobile experience.
Security & Privacy
Data is scrambled while being sent to their servers
Data is scrambled when stored on their servers
Where servers are located — affects which governments can request your data
Privacy policy summary
Hypothesis stores annotations on its servers. Public annotations are visible to anyone — including unauthenticated API users, anyone viewing the Hypothesis stream, and anyone with the browser extension. Private and group annotations are access-controlled. Hypothesis does not sell user data. No advertising. The nonprofit/PBC structure means no VC-driven data monetization pressure, though the $14M seed round from Anno introduces commercial incentives for the education market.
How to protect yourself:
Default to private or group-only annotations for unpublished research. Public annotations reveal both what you're reading and what you're thinking about it — treat public mode as publishing. Use group permissions to limit visibility for sensitive collaborative work. For high-risk reporting, consider that annotation metadata (timestamps, URLs visited) creates a pattern even if individual notes are private. The browser extension phones home to Hypothesis servers on every page load where it's active.
Open source (BSD 2-Clause license) with nonprofit+PBC governance. No data monetization. Completed Cloud Security Alliance CAIQ assessment. Regular vulnerability testing. Hosted on AWS. Annotations stored on Hypothesis servers — public annotations are fully discoverable by anyone, including unauthenticated users. Access controls exist for private and group annotations. No published SOC 2 Type II audit. The extension's always-on nature creates browsing metadata that journalists in sensitive contexts should weigh carefully.
Who Owns This
Known issues
Public annotations are discoverable by default — this is a feature, not a bug, but journalists often don't realize their reading patterns are visible. The browser extension activates on every page, which means Hypothesis knows what URLs you visit even if you don't annotate. PDF annotation requires OCR-enabled PDFs; scanned documents without OCR won't work. Mobile experience is significantly worse than desktop. Image annotation (added mid-2025) only works in PDFs, not on web pages. No offline mode. The W3C standard compliance is real but interoperability with other annotation tools remains theoretical — in practice, your annotations live on Hypothesis servers. Genius Web Annotator is effectively dead; Diigo exists but has reliability issues and a paid tier for basic features. Hypothesis is the last credible open-source web annotation tool standing.
Pricing
Free for individuals and groups. Hypothesis for Education (LMS-integrated): custom pricing per institution. Enterprise tier for organizations needing SSO, analytics, and admin controls.
This is an editorial assessment based on publicly available information as of 2026-04-02, using our published methodology. Independent security review is pending. Security posture can change at any time. This is not a guarantee of safety.
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