- Is this really free with no watermark?
- Yes. There is no account, no paywall, and no watermark added to your file. The tool is built with open-source libraries (PDF.js and pdf-lib) that run entirely in your browser. We never see your file — it is processed locally on your device. Revenue for Knackpad comes from advertising, not from charging you or degrading your output.
- Does my PDF get uploaded to a server?
- No. When you "open" a file with this tool, your browser reads it directly from your local disk using the File API. The PDF bytes never leave your machine. There is no backend, no storage, and no analytics attached to the file itself. This makes it safe to use with confidential, legal, or medical documents.
- What can I write or draw on the PDF?
- You can add freehand pen strokes in any color and size — useful for signatures, annotations, arrows, or circling items. You can also place text boxes anywhere on a page and type into them. The Erase tool lets you remove any stroke you drew. All annotations are vector-embedded by pdf-lib so they stay crisp when you print or zoom in.
- Can I edit text that was already in the PDF?
- No. This tool adds new content on top of existing PDF pages — it does not reflow or remove existing text. If you need to replace body text inside a PDF, you need a full PDF editor like Adobe Acrobat. For filling in forms, signing, circling things, or adding handwritten notes, this tool is exactly right.
- What file size or page count limits are there?
- There is no hard limit enforced by this tool — your browser's available memory is the practical ceiling. In testing, PDFs up to about 50 MB and 100 pages work well on a modern laptop. Very large or heavily scanned PDFs may be slower to render. If a page is slow, try zooming your browser out first so the canvas renders at a smaller pixel size.
- Will the downloaded PDF keep my original quality?
- Yes for the original content. pdf-lib copies the original PDF pages byte-for-byte and overlays your annotations as vector drawing operations (lines and text), so the base document is not re-encoded or compressed. Your annotations will look sharp at any zoom level.