Free PDF Highlighter & Annotator Tool
Instantly highlight text, draw freehand annotations, and export your marked-up PDFs directly in your browser. 100% free, secure, and private – your files never leave your device.
Upload PDF to Annotate
Drag & drop your file here, or click to browse (Max 50MB)
Annotations Saved!
Your document is ready for download.
Steps to Use Free PDF Highlighter
Upload Securely
Choose or drag and drop your PDF. Processing happens locally on your device, ensuring total privacy.
Markup & Annotate
Toggle between smart text highlighting for documents and the freehand pen for marking up scanned images.
Save Your Workspace
Export your progress as a lightweight JSON file so you can import it later and resume working right where you left off.
Download PDF
Export your final document with all highlights and ink strokes permanently embedded into the file.
Why Use Our Free PDF Highlighter ?
Whether you are a student reviewing lecture slides, a researcher analyzing academic papers, or a professional signing contracts, our Free Online PDF Annotator gives you premium markup tools without the expensive software subscriptions. Unlike standard PDF readers, our tool offers a dual-layer engine: use the smart text-selector to perfectly highlight sentences, or switch to the freehand pen to circle charts, sign documents, and draw on scanned images.
Total Privacy & Security
We prioritize your data security. This tool is built with 100% browser-based processing. When you upload a document, it is never sent to our servers, stored in a database, or seen by anyone else. All rendering, highlighting, and saving happens locally on your computer’s own memory, making it entirely safe for confidential legal documents, financial statements, and personal records.
The Power of JSON: Save States & Data Extraction
What truly sets this tool apart is our unique JSON Export/Import feature, designed specifically for power users.
- Save Your Progress: Working on a massive 100-page document? You don’t have to finish in one sitting. Click “Export JSON Data” to save your workspace. Tomorrow, simply upload your PDF and import that JSON file to instantly restore all your highlights and pen strokes exactly where you left them.
- Extract Raw Data: For researchers and data analysts, the JSON file contains the raw text of everything you highlighted. You can easily copy this data into Notion, Excel, or feed it into AI tools like ChatGPT for instant summarization without manually typing out quotes.
Frequently Asked Questions
Are my PDF documents safe? Are they uploaded to your servers?
Yes, your documents are 100% safe. Our tool uses local browser processing. Your PDF never leaves your computer, and no data is ever uploaded to our servers. All highlighting and saving happens directly on your own device.
What is the JSON file export used for?
The JSON file acts as a “Save State” for your workspace. If you are highlighting a large document, you can export the JSON file before closing your browser. The next time you visit, simply upload the PDF and import the JSON file to instantly restore all your highlights and drawings. It is also useful for researchers who want to extract their highlighted text as raw data.
Can I draw on scanned PDFs or images?
Will my highlights and drawings show up if I send the PDF to someone else?
Yes. When you click “Download PDF,” our engine permanently embeds your text highlights and vector pen strokes into the document. It will display perfectly in Adobe Acrobat, Chrome, Mac Preview, or any standard PDF reader.