Protect PDFs with a watermark

Filemonk can stamp the PDFs you choose with the buyer’s own details before they download it. It applies to files Filemonk hosts, not ones you link from Google Drive or Dropbox. Two people buying the same ebook get two different files. If one turns up on a sharing site, the watermark tells you which order it came from, and the fact that it happens at all discourages the sharing in the first place.

Before you begin

• PDF watermarking is on paid plans. The app shows an upgrade prompt otherwise. See Filemonk pricing and plans.
• It applies to PDFs only, and to PDFs that Filemonk hosts. Files added by link are handed over untouched.
• Watermarking is applied when the customer downloads, so large PDFs can take a moment the first time.

Set it up

Turn it on

1. Click Filemonk in the left menu of your Shopify admin.

2. Click Settings in the app’s menu.

3. Open the PDF protection tab.

4. Switch on PDF Watermark, in the card of the same name. The badge beside it changes from Off to On.

   

5. Two options appear under the toggle. Choose the scope:

   1. Stamp all PDFs, which watermarks every PDF you sell.
   2. Stamp specific PDFs, which watermarks only the files you pick. With this chosen, open each PDF in your Content library and tick Protect PDF with watermark in its Settings card. A banner below the options carries a Go to Content library link that takes you there.

   

Design the watermark

1. On the same tab, in the Watermark PDFs card, click Customize PDF watermark to open the watermark editor.

2. In Text, write what should appear on the page. Click Variables to insert the buyer’s details rather than typing fixed text. You can use the order name, the order email, the customer’s email or phone, the customer name, the purchase date, and your store name.

3. Choose a Style, which is where the watermark sits: diagonally across, in the center, at the top, bottom, or any corner.

4. Set Opacity, so it is readable without ruining the page.

5. Set Font name, Font color as a hex value like #000000, and Font size.

   

6. Check the preview beside the controls, then click Save.

A watermark carrying the customer’s email is the most useful for tracing a leak. A diagonal, low-opacity stamp across the page is the hardest to crop out.

What customers will see

Their PDF, with your watermark on it and their own details in it. There may be a short wait on the first download of a large file while it is stamped.

Check your setup

Place a test order for a product with a PDF and download it. Confirm the watermark appears, is readable, does not cover the content, and shows the right buyer details. See Create a test order.

Troubleshooting

The watermark isn't on the downloaded PDF

Check in this order:

1. PDF Watermark is on, on the PDF protection tab.
2. If you chose Stamp specific PDFs, that file has Protect PDF with watermark ticked in your content library.
3. The file is a genuine PDF, not another format named .pdf.
4. The file is uploaded to Filemonk rather than added by link.
5. Your plan includes watermarking.

Watermarking is currently disabled due to high error rates

Filemonk switches watermarking off automatically when more than half of your PDFs fail to stamp, rather than serving broken files. It usually means the PDFs are encrypted, password protected, or malformed. Re-export them from your original source and replace them, then contact support to confirm you are clear.

The download is slow since I turned this on

Each PDF is stamped before it is served, and large documents take longer. This is normal for the first download of a file. If it is consistently slow on very large PDFs, contact support.

The watermark covers the text and customers complain

Lower the Opacity, reduce the Font size, or move it out of the body with a corner or bottom Style. Diagonal at low opacity is usually the best balance.

The watermark shows the variable name instead of the customer's details

The variable was typed by hand and does not match. Clear the field and insert it from Variables so it is exact.

I replaced a PDF and the watermark looks stale

Replacing a file clears the stamped copies prepared for existing orders, and the new file is stamped again on the next download. Download once more to see it. See Replace a file.

FAQ

Can a customer remove the watermark?

A determined person with the right software can, and no watermark survives a screenshot-and-rebuild. It is a deterrent and a tracing tool, not an unbreakable lock. See How Filemonk protects your files.

Does it apply to PDFs customers already bought?

Yes, if the file has never been stamped for that order. Stamping happens at download, so a past buyer returning for another download gets a watermarked copy, and the copy they already saved stays as it was. Changing your watermark text later does not restamp files that were already stamped: those orders keep the wording they were given. Replacing or editing the file clears its stamped copies, and the next download is stamped afresh with your current text.

Can I watermark some PDFs but not others?

Yes. Choose Stamp specific PDFs instead of Stamp all PDFs, then tick Protect PDF with watermark on each file in your content library that should be stamped. Useful when a sample chapter can go out clean but the full book should not.

What about EPUB, ZIP, audio, or video?

Not watermarked. Protect those with download limits, login requirements, and access rules instead.

Someone shared my PDF. What now?

Open the shared copy and read the watermark to find the order, then disable that order’s access so it stops working. See Disable access to downloads for any order.

Related guides

• How Filemonk protects your files, for the other layers.
• Replace a file, and what it means for stamped copies.
• Limit the number of downloads per order, to pair with watermarking.