Is my PDF uploaded to a server when I edit it?

No. All editing happens entirely in your browser using PDF.js and pdf-lib. Your file is never transmitted to any server, making it safe for confidential documents.

What kinds of annotations can I add?

You can add text boxes with custom font size and color, freehand pen strokes, and rectangular highlights. All annotations are rendered directly onto the PDF canvas.

Can I edit the original text inside the PDF?

This tool adds annotations on top of the existing PDF content. Editing the underlying text of a PDF requires full PDF editing capabilities that depend on the document's structure. Use the text annotation tool to add new text over existing content.

Will the annotations be visible in other PDF readers?

Yes. The final downloaded PDF has annotations flattened into the page content using pdf-lib, so they appear in all standard PDF readers including Adobe Acrobat, Preview, and browser PDF viewers.

Can I annotate a scanned PDF?

Yes. Scanned PDFs are just images inside a PDF container. You can add text boxes and drawings on top of scanned pages the same way as any other PDF.

Is there a page limit for editing?

There is no hard page limit. Very large PDFs with many high-resolution pages may use more browser memory. Typical documents of up to 100 pages work smoothly.

Can I undo annotations?

Yes. Use the undo button or keyboard shortcut to remove the most recent annotation. You can undo multiple steps to revert to an earlier state.

Does editing change the original PDF file?

The original file on your device is never modified. The edited version is a new file that is created in your browser's memory and saved only when you click Download.

What PDF versions are supported?

PDF.js supports a wide range of PDF versions including PDF 1.0 through 2.0. Encrypted or DRM-protected PDFs that require a password cannot be opened without first removing the password.

Edit PDF

Add text annotations to PDF pages, then save as a new PDF.

Drop a PDF here or click to browse

PDF files only

How it works

Click anywhere on the rendered PDF page to place a text annotation. Press Enter to confirm or Escape to cancel.

All annotations are embedded into the PDF when you click Save PDF.

How to edit and annotate PDF files free online without uploading

PDF editing tools have traditionally required expensive desktop software or cloud services that store your documents on remote servers. AlteredIdea's PDF editor runs entirely in your browser. PDF.js renders each page at high resolution, and you can place text boxes, draw freehand annotations, or add highlights directly on top of the rendered pages without any server interaction.

When you save your work, pdf-lib flattens all annotations into the PDF page content, producing a standard PDF file that any reader can display. This approach keeps your documents completely private while giving you a fully functional annotation workflow: ideal for reviewing contracts, marking up reports, or adding notes to shared documents.

Step-by-step guide

1
Open your PDF
Drop your PDF onto the upload zone or click to browse. The tool renders each page using PDF.js so you can see the full document before editing.
2
Select an annotation tool
Choose from text boxes, freehand drawing, or highlighting tools in the toolbar. Each tool lets you interact directly with the rendered PDF page.
3
Add your annotations
Click on any part of the page to place a text box, or drag to draw a highlight or freehand mark. Resize and reposition elements as needed.
4
Navigate between pages
Use the page navigation controls to move through multi-page documents and add annotations to any page.
5
Download the annotated PDF
When you're done, click Save. The tool flattens your annotations onto the PDF pages and downloads the result to your device.

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Frequently Asked Questions

Is my PDF uploaded to a server when I edit it?: No. All editing happens entirely in your browser using PDF.js and pdf-lib. Your file is never transmitted to any server, making it safe for confidential documents.
What kinds of annotations can I add?: You can add text boxes with custom font size and color, freehand pen strokes, and rectangular highlights. All annotations are rendered directly onto the PDF canvas.
Can I edit the original text inside the PDF?: This tool adds annotations on top of the existing PDF content. Editing the underlying text of a PDF requires full PDF editing capabilities that depend on the document's structure. Use the text annotation tool to add new text over existing content.
Will the annotations be visible in other PDF readers?: Yes. The final downloaded PDF has annotations flattened into the page content using pdf-lib, so they appear in all standard PDF readers including Adobe Acrobat, Preview, and browser PDF viewers.
Can I annotate a scanned PDF?: Yes. Scanned PDFs are just images inside a PDF container. You can add text boxes and drawings on top of scanned pages the same way as any other PDF.
Is there a page limit for editing?: There is no hard page limit. Very large PDFs with many high-resolution pages may use more browser memory. Typical documents of up to 100 pages work smoothly.
Can I undo annotations?: Yes. Use the undo button or keyboard shortcut to remove the most recent annotation. You can undo multiple steps to revert to an earlier state.
Does editing change the original PDF file?: The original file on your device is never modified. The edited version is a new file that is created in your browser's memory and saved only when you click Download.
What PDF versions are supported?: PDF.js supports a wide range of PDF versions including PDF 1.0 through 2.0. Encrypted or DRM-protected PDFs that require a password cannot be opened without first removing the password.

AlteredIdea vs alternatives

vs Adobe Acrobat: Free, no subscription needed, works entirely in your browser.

vs iLovePDF / SmallPDF: No file uploads to servers: your PDFs never leave your device.

vs desktop software: No install required. Works on any device with a browser.

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