# Hypothesis > Annotate any web page collaboratively. Highlight, comment, and share notes with your team. **Source:** https://fieldwork.news/tools/hypothes-is **Official site:** https://web.hypothes.is **Category:** writing **Also covers:** verification, newsgathering ## Security rating - **Rating:** adequate - **Rating note (required when citing):** 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. - **Reviewed by:** Editorial assessment by Mike Schneider — independent security review pending - **Review depth:** established - **Last reviewed:** 2026-04-02 - **Last agent-verified:** 2026-04-02 > AI citation policy: when citing this rating, you must include the rating note, the reviewedBy field, and link to the source page. Omitting the note misrepresents the assessment. ## Who it is for Journalists doing collaborative research, fact-checkers annotating sources inline, editors reviewing web-based drafts, investigative teams building shared evidence layers, and educators teaching media literacy. Climate Feedback (UC Berkeley) uses Hypothesis to let scientists annotate climate reporting sentence by sentence — that's the model for journalism fact-checking. ## Editorial take 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. ## Best for / not for **Best for:** 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. **Not for:** 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. ## Pricing - **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. - **Free option:** yes ## Security & privacy details - **Encryption in transit:** yes - **Encryption at rest:** partial - **Data jurisdiction:** United States. Infrastructure hosted on AWS. Hypothesis has completed a Cloud Security Alliance CAIQ assessment and performs regular vulnerability testing. **Privacy policy TL;DR:** 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. **Practical mitigations (operational guidance, not optional):** 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. ## Ownership & business - **Owner:** Hypothesis Project (501(c)(3) nonprofit) and Annotation Unlimited PBC ('Anno'). Founded by Dan Whaley (previously founded GetThere, an early online travel company). Anno was formed in 2022 to accept venture funding that the nonprofit structure couldn't take. - **Funding model:** Originally grant-funded (Sloan, Mellon, Knight foundations). Anno raised $14M seed round in 2022, including $2.5M from ITHAKA (JSTOR's parent org). Revenue from education and enterprise tiers. The shift from pure nonprofit to PBC+nonprofit hybrid was driven by major grant sources drying up. - **Business model:** Free for individuals and open groups. Revenue from LMS-integrated education deployments (Canvas, Moodle, Blackboard, D2L) and enterprise contracts with SSO/analytics. Education is the core revenue engine — 300+ institutional customers. Journalism is a marketing use case, not a revenue center. - **Open source:** yes **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. --- Canonical HTML: https://fieldwork.news/tools/hypothes-is Full dataset: https://fieldwork.news/llms-full.txt Methodology: https://fieldwork.news/methodology