PDF Editor — Gratis online tool

Free Online PDF Editor — Annotate, Highlight & Manage Pages

Toololis PDF Editor lets you edit PDF files directly in your browser without uploading to any server. Add text annotations, highlight important sections, delete unwanted pages, rotate pages, and reorder them by dragging. All processing uses pdf-lib and pdf.js, running entirely on your device for complete privacy.

Whether you need to annotate a contract, highlight key sections of a report, remove blank pages from a scan, or rearrange pages in a presentation, this tool handles it without requiring any software installation or account creation.

Key Functies

• Text annotations — click anywhere on a PDF page to add text. Choose font size and color for your annotations.
• Highlight tool — draw semi-transparent rectangles over important text or areas. Choose any color for your highlights.
• Page management — delete, rotate (90 degrees), and reorder pages. Drag thumbnails in the sidebar to rearrange.
• Visual page preview — every page is rendered as a canvas thumbnail for easy navigation and overview.
• Client-side processing — uses pdf-lib for PDF modification and pdf.js for rendering. Neething is uploaded anywhere.
• Download modified PDF — save the edited PDF with all annotations and page changes embedded permanently.

How PDF Editing Works in the Browser

Traditional PDF editors require desktop software because PDF is a complex binary format. This tool uses two powerful JavaScript libraries to bring PDF editing to the browser: pdf.js (developed by Mozilla) renders PDF pages as canvas images for display, while pdf-lib provides low-level PDF manipulation capabilities including adding text, drawing shapes, and managing pages.

When you add a text annotation, the tool records its position relative to the PDF page coordinates. When you download, pdf-lib opens the original PDF bytes, draws the annotation text and highlights at the correct positions, and outputs a new PDF file. The result is a standards-compliant PDF that works in any viewer.

What You Can and Cannot Edit

This tool excels at adding content to PDFs — text annotations, highlights, and page management. It does not modify existing text in the PDF. Editing existing text would require a full PDF reflow engine that understands the document's font metrics, layout, and text flow, which is beyond what browser-based tools can reliably do.

For tasks that require editing existing PDF text, you would need a desktop application like Adobe Acrobat or LibreOffice. However, for annotation, markup, and page management, this browser-based editor is faster and more convenient than installing software.

Tips for Better Results

• Use the zoom controls in your browser (Ctrl/Cmd + scroll) to get a closer view when placing annotations precisely.
• Choose contrasting colors for text annotations — red or blue text on a white document background is most readable.
• For highlights, use yellow or green at the default semi-transparency for a natural highlighter effect.
• Delete blank pages before adding annotations to keep your workflow focused.
• Reorder pages by dragging them in the sidebar — the final PDF will reflect the new page order.

Privacy and Security

Your PDF never leaves your browser. The file is read into memory using the FileReader API, processed by pdf.js and pdf-lib in JavaScript, and the modified PDF is generated as a Blob for download. Nee server communication occurs during the entire editing process. This makes the tool suitable for sensitive documents including contracts, financial statements, and personal records.