Title:
How Developers Add Custom Stamps and Text Watermarks to PDFs with One Simple API Call
Meta Description:
Add custom stamps or text watermarks to your PDFs instantly with imPDF Cloud PDF REST APIfast, easy, and perfect for developers.
Every time I sent out a PDF contract, I worried it'd be tampered with.
I'd tried everythingmanual watermarking, overly complex PDF editors, even open-source tools that felt like they hadn't been updated since 2010.
Nothing clicked.
It took me forever to apply the same stamp to 200+ documents. Clients got inconsistent versions. And when legal flagged a missing watermark in a signed deal? That was my breaking point.
Then I found imPDF Cloud PDF REST API.
Not even kiddingone API call and my PDF had a text watermark, exactly where I wanted it, at the font size and opacity I needed. Boom. Done.
Why imPDF Cloud PDF REST API hit different
Here's what got me:
It wasn't bloated.
No extra fluff.
No 3-hour onboarding sessions.
Just the exact tools I needed in a developer-friendly REST format.
And that matters. I don't want a full-blown software suiteI want a flexible, no-BS solution that works with my stack, not against it.
I stumbled across https://impdf.com/ looking for something quick and cloud-based. Five minutes later I was using Postman to run tests. Ten minutes later I was dropping watermarks onto every outgoing proposal with consistent branding.
Who should be using this
If you're a:
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Developer building document workflows
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SaaS product manager overseeing digital signatures
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LegalTech dev managing contract lifecycle
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HR lead sending out employment offers
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Operations team standardising report branding
This is for you.
Especially if you're tired of:
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Janky command-line PDF tools
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Expensive enterprise PDF software
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"Free" tools that inject ads or lose formatting
How I used imPDF to watermark 300+ docs in under an hour
Here's the real use case that sold me:
Problem:
I needed to batch-stamp every PDF invoice going out with "COPY DO NOT PAY" in red, rotated at 45 degrees, across the page.
Old process:
Open. Add text. Resize. Save. Repeat.
New process:
Wrote one Python script using the Watermark PDF API endpoint from imPDF. It called their REST API with these params:
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Text: "COPY DO NOT PAY"
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Colour: Red (#FF0000)
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Font size: 50
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Rotation: 45 degrees
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Opacity: 0.3
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Position: Center
Uploaded the files with their Upload Files API, hit the Watermark endpoint, and downloaded the batch with Zip Files API.
Time saved?
Honestly, hours.
Consistency? Perfect.
Headache? Gone.
Other tools I've used before vs imPDF
Let's break it down real quick:
Adobe Acrobat Pro:
Great UI. Horrible automation. Not scalable.
Open-source libraries:
Clunky. Poor documentation. Good luck with font styling.
Other REST APIs I tried:
Either missing key options (like opacity), or had weird rate limits that broke my flows.
imPDF nailed it.
Here's why:
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Fully documented endpoints
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Works in any language (Python, PHP, JS, etc.)
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Instant validation with API Lab (test + generate code before writing your own)
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Free to tryno credit card, no surprises
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Handles massive file batches with ease
3 underrated features that made my life easier
1. API Lab
Before this, I'd never seen a dev tool that lets me preview outputs before coding.
With API Lab, I could:
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Upload a file
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Set watermark text/position
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Get a preview
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Then copy/paste the auto-generated cURL or Python code into my app
Fastest prototyping ever.
2. Combine + Watermark in one flow
You can chain endpointsso I merged PDFs first using Merge PDFs API, then applied a text watermark to the result.
All in the same script.
3. Text + Image stamps
Need your company seal stamped across documents?
Upload your image.
Call the Add to PDF API.
Set exact X/Y positions.
Done.
You could even add both an image and text watermark in the same call.
Why this is a game-changer for SaaS tools
Building your own document workflow?
imPDF integrates like it was built just for devs:
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Works seamlessly with Node.js, Python, .NET, PHP, JavaScript
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Offers endpoints for every use caseconversion, security, stamping, OCR
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Supports batch ops, asynchronous polling, and file zipping
Instead of reinventing the wheel, you can focus on your app logic. Let imPDF handle the PDF pain.
Need something more specific?
Here's the kicker: imPDF also builds custom tools.
Need a Windows virtual printer that intercepts print jobs and saves them as watermarked PDFs?
Need a hook layer to capture Windows API events in real time?
Need a barcode-enabled OCR layer that extracts form data from scanned images?
They can build that for you.
And not just for Windowsthey work with Linux, macOS, Android, server environments, and cloud platforms.
They'll even customise for:
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C/C++, Python, PHP, .NET, HTML5, iOS, JavaScript
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Advanced PDF security + DRM
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OCR table recognition for TIFFs and scanned forms
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Document conversion pipelines
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Print job monitoring
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Digital signature tech
Just hit them up at: http://support.verypdf.com/
Bottom line
If you're tired of clunky PDF workflows
If you're building something that touches a ton of documents
And if you want your PDFs branded, protected, and polishedautomatically
Then yeahI'd recommend imPDF Cloud PDF REST API all day.
It's fast.
It's flexible.
And it actually makes PDF dev work fun (never thought I'd say that).
Click here to try it out for yourself: https://impdf.com/
Start your free trial now and boost your productivity.
FAQs
Q: Can I apply different watermarks to different pages in the same PDF?
Yesusing conditional logic in your script, you can call the API multiple times for page-specific watermarks.
Q: Does imPDF support image-based watermarks?
Absolutely. Just upload your image and use the Add to PDF API with X/Y coordinates.
Q: Can I batch process 500+ PDFs in one go?
Yes, using Upload Files API and Zip Files API for batching and result download.
Q: Is there a way to preview the watermark before applying it?
Yes! That's what API Lab is fortest your parameters, preview the output, then copy the code.
Q: What happens if a PDF is encrypted or locked?
Use the Decrypt PDF API first, then apply your watermark as needed.
Tags/Keywords
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