Free · No sign-in · Files stay local

A LaTeX PDF Annotator for Academic Work

Designed for marking, feedback, and working with PDFs in the browser.

Getting Started (2m57s)

A short overview of annotation, comments, and basic PDF editing.

Marking & Grading Demo (3m28s)

An example marking workflow using mark stamps, feedback, and the comment library.

Blackboard Bulk Marking (5m54s)

How to bulk-download Blackboard assignments and mark them faster with Annotarium.

Tools for Marking and Annotation

A growing set of tools for marking work, adding feedback, and editing PDFs.

LaTeX Annotations

Add equations and symbols to your PDFs using LaTeX.

Marking Schemes

Set up marking schemes with question-level totals.

Comment Library

Save and reuse comments, feedback snippets, and images.

Drawing Tools

Pen, highlighter, shapes, arrows, and stamps.

PDF Editing & Merging

Add, delete, or rearrange pages. Merge PDFs or insert templates.

Works Everywhere

Runs in any modern browser with no installation. Optimized for desktop; tablet and pen support improving.

Editable .annot Files

Save PDFs and annotations separately, so work stays fully editable. Reopen and continue where you left off.

Optional File Encryption

Protect annotated work with password-encrypted .annot files (PBKDF2 + AES-256-GCM).

Coming Soon

AI Assistant

Exploring AI-assisted grading, handwriting recognition (OCR), and feedback tools.

Your Privacy, Protected

Annotarium is designed so your documents stay in your browser.

  • All processing happens locally in your browser
  • PDFs and annotations are never uploaded to any server
  • No sign-in required to start using Annotarium
  • Hosted on Cloudflare, with an A-grade security configuration

Annotarium is actively developed and continues to evolve based on academic use.