Annotarium is a browser-based LaTeX PDF annotator for marking and feedback. It lets you add mathematical equations, comments, and annotations directly onto PDFs without any installation.
Yes, the core app is free to use. No payment or subscription required. Future AI assistant features may have an additional cost.
No sign-in is required. You can start using Annotarium immediately by opening a PDF. Just go to app.annotarium.org and drag in a file.
Annotarium works in Chrome, Firefox, Safari, and Edge. Any modern browser with JavaScript enabled will work. For the best experience, use the latest version of your browser.
No. All processing happens locally in your browser. Your PDFs and annotations never leave your device. This means your documents remain private and secure.
Use File → Save to save your annotations as a .annot file. This preserves all annotations and can be reopened and edited later. To share with others, use File → Export to create a flattened PDF.
Flattening permanently embeds your annotations into the PDF. The exported file can be opened in any PDF reader (Adobe, Preview, etc.) and the annotations appear as part of the document.
Select the text tool and type LaTeX between dollar signs. For example: $x^2 + y^2 = r^2$ will render as a proper equation.
Marking schemes let you save reusable feedback comments. Create a library of common remarks and insert them with one click. Useful for grading multiple assignments consistently.