Annotate PDF

Annotate a PDF without uploading it.

Highlight text, add sticky notes, draw arrows and shapes, write freehand, all in your browser. Your document never leaves your device.

A document sealed inside a Faraday cage. Your files stay fully private, on your device. A document sealed inside a Faraday cage. Your files stay fully private, on your device.

Annotating a document means reading it closely. It should stay private.

Reviewing a contract, marking up a draft, or leaving feedback on a report all require you to engage deeply with the content, which usually means the document contains something sensitive. Annotation tools that require an upload put your confidential review copy on a server you don't control.

The difference in one sentence

A document you're marking up is one you've read carefully, which means it's probably sensitive, and shouldn't be uploaded to annotate it.

KeptPDF runs its entire annotation engine in your browser. Highlights, comments, and drawings are all baked into the PDF locally. Nothing is sent to a server. Open developer tools and watch the Network tab while annotating: your document never appears in a single request.

How to annotate a PDF

On your device. No account needed, and nothing gets uploaded.

1. Open your PDF

Drop the file onto the page. It loads in your browser without being sent anywhere.

2. Add annotations

Highlight text, add sticky notes, draw arrows or rectangles, sketch freehand, or stamp text anywhere on the page.

3. Download the annotated PDF

Your annotations are baked into the file and visible in any PDF viewer.

The full annotation set. Nothing uploaded.

Highlights and text

Select text to highlight it in yellow, or place text boxes anywhere on the page. Good for marking key clauses or leaving inline comments.

Shapes and arrows

Draw rectangles, ellipses, lines, and arrows to call out specific areas or diagram relationships on the page.

Freehand drawing

Sketch notes, underline manually, or draw anything freehand with the pen tool. Works with a mouse or touchscreen.

No upload or account needed

Annotate free with no sign-up, no daily limit. Pro ($29/month) supports larger files (hundreds of MB practical limit, browser memory dependent).

More document editing tools

Questions, answered.

How do I annotate a PDF for free?
Open KeptPDF's Annotate tool, drop in your PDF, and use the toolbar to highlight, add text, or draw. Download when finished. It's free with no account, no daily limit.
Will annotations show in other PDF viewers?
Yes. KeptPDF bakes annotations directly into the PDF. They appear as permanent visual elements in any viewer, including Adobe Acrobat, Preview, and browser PDF viewers.
Can I annotate on my phone or tablet?
Yes. KeptPDF works in mobile browsers. The freehand drawing tool responds to touch input, so you can sketch with your finger on a tablet.
Is my document uploaded to a server?
No. All annotation processing happens in your browser, and the document is never uploaded anywhere.
Can I remove annotations after saving?
Once the annotated PDF is saved, the annotations are baked in. If you need a clean copy, keep the original before annotating.
Is it free?
Yes. Free with no account, no daily limit. Pro ($29/month) supports larger files (hundreds of MB practical limit, browser memory dependent).

Annotate a PDF. Free, in your browser.

Open Annotate PDF