Apply image watermarks to PDFs with Nutrient Document Web Services API on Zapier

This tutorial walks you through adding an image watermark to your PDFs using the Nutrient Document Web Services API on Zapier. You’ll trigger the workflow when a new PDF is uploaded to Google Drive, apply an image-based watermark, and save the final PDF to a different folder.

Illustration: Apply image watermarks to PDFs with Nutrient Document Web Services API on Zapier

What is Zapier?

Zapier is an automation platform that connects your favorite apps and services with no code required. You can build “Zaps” to automate repetitive tasks by setting up triggers and actions between apps like Google Drive, Slack, Gmail, and more.

In this tutorial, you’ll learn how to use Zapier to add image watermarks to PDFs using the Nutrient API.

What is the Nutrient API?

Nutrient Document Web Services API is a powerful platform for document automation. With your free account, you get 100 credits, which you can use to perform various document operations. Each tool (e.g. conversion, signing, flattening) consumes a different amount of credits depending on complexity.

Nutrient offers more than 30 tools with the ability to:

Convert images and documents to PDF
Merge, split, or reorder pages
Add digital signatures, watermarks, or annotations
Run OCR, redact, flatten, and more

All you need is an API key from a free account to get started. You can chain these tools together in Zapier to build powerful, automated PDF workflows.

What you’ll need

A Zapier account (a pro plan is necessary for multi-step Zaps)
A Google Drive account
A PDF file uploaded to a Google Drive folder
A Nutrient Document Web Services API key — sign up here

Step 1 — Trigger a new file in a Google Drive folder

Select Google Drive as the trigger app.

Select Google Drive as the trigger app in Zapier

Choose the New File in Folder trigger event.

Choose ‘New File in Folder’ as the trigger event

Connect your Google Drive account.
Configure the trigger:

In the Drive field, select your Google Drive.

Select which Drive to monitor for new PDF files

In the Folder field, select or create a folder (e.g. nutrient).

Choose or create the folder to watch for new PDFs

Ensure that the option for Include Deleted Files? is set to Only return non-deleted files.

Once configured, test the trigger by selecting a sample PDF file from the folder to confirm it’s being pulled into the Zap correctly.

Test the trigger by pulling in a sample PDF file

Step 2 — Apply watermark to PDF action (Nutrient API)

Next, select Nutrient Document Web Services API as the app.

Select Nutrient Document Web Services API as the action app

Choose the Apply Watermark to PDF action.

Choose the ‘Apply Watermark to PDF’ action from the list

Connect your Nutrient API account by entering your API key.

Paste your Nutrient API key into the connection field

You can find your API key in the Nutrient dashboard.

Locate your API key in the Nutrient dashboard

Fill out the following fields:
- PDF File URL — From step 1 (Google Drive)
- Watermark Image URL — This can be handled in two ways, outlined below.

Option 1 — Static image: If you’re always using the same image

Upload the image to Google Drive.
Make it publicly accessible so anyone with the link can view it.
Use a direct download link by replacing the share link like this: https://drive.google.com/file/d/FILE_ID/view?usp=sharing > https://drive.google.com/uc?export=download&id=FILE_ID

For example, this: https://drive.google.com/file/d/1pxou2rdOCELaWEjMoxAIVG9kC_G-u-hD/view?usp=sharing becomes: https://drive.google.com/uc?export=download&id=1pxou2rdOCELaWEjMoxAIVG9kC_G-u-hD

Configure the action: map the PDF file URL, watermark image URL, and output file name

Make sure the watermarked image file is set to Anyone with the link in Google Drive so it can be used in the API call.

Option 2 — Dynamic image: If the image varies per file

Add a new step: Google Drive > Find File.
Search by name (e.g. logo.png) and use the Web Content Link output.
Make sure the file is shared publicly.
Fill the Output File Name field — Optional (e.g. branded_file.pdf).

The file must be accessible via a public URL or direct download link (Zapier will handle this if sourced from Google Drive).

Test this step to ensure the watermark is correctly applied.

Run a test to verify the watermark is applied to the PDF

Step 3 — Upload the watermarked PDF to Google Drive

Now, add another step by selecting Google Drive as the app and Upload File as the action event. Connect your Google Drive account if needed.

Select Google Drive ‘Upload File’ as the action step

Select your drive and the folder where the updated PDF should be saved. In the File field, use the output from the Nutrient API step. Optionally, set a custom file name or extension to keep things consistent and organized.

Map the output from the watermark step to upload back to Google Drive

Zapier may warn you about a potential Zap loop if you use the same folder for the input and the output. You can avoid this by uploading the updated file to a different folder.

Run a complete test of the Zap to confirm:

The PDF file is pulled in.
The image watermark is applied successfully.
The watermarked PDF is saved to your output folder.

Once everything works as expected, click Publish.

Final test step showing the upload of the watermarked PDF to Google Drive

Conclusion

With this Zap, you’ve automated watermarking of PDF files using a custom image. This is ideal for branding, approvals, or document classification. Combine this workflow with other Nutrient actions to build robust document pipelines.

Author

Hulya Masharipov Technical Writer

Hulya is a frontend web developer and technical writer at Nutrient who enjoys creating responsive, scalable, and maintainable web experiences. She’s passionate about open source, web accessibility, cybersecurity privacy, and blockchain.

Explore related topics

Zapier Nutrient API PDF Watermark Google Drive Automation