Add professional text watermarks to any PDF document with full control over position, opacity, font size, color, and rotation. Stamp documents with CONFIDENTIAL, DRAFT, your brand name, or any custom text across every page. The watermark is rendered as selectable, high-quality text with Unicode support. Ideal for branding, copyright protection, document status marking, and legal workflows. Upload a PDF and receive a downloadable watermarked file.
{"success":true,"url":"https://pub-6db99bab215e44889f46c4b2a619f8c5.r2.dev/watermarked/20260619/f977168b-1b94-4749-a97a-0e90c2cc6af3.pdf","watermark_type":"text","pages_watermarked":5,"processing_time":"673ms"}
curl --location 'https://zylalabs.com/api/12964/pdf+text+watermark+api/25882/add+text+watermark?text=CONFIDENTIAL BRO&rotation=Optional' \
--header 'Content-Type: application/json' \
--form 'image=@"FILE_PATH"'
After signing up, every developer is assigned a personal API access key, a unique combination of letters and digits provided to access to our API endpoint. To authenticate with the PDF Text Watermark API simply include your bearer token in the Authorization header.
| Header | Description |
|---|---|
Authorization
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Required
Should be Bearer access_key. See "Your API Access Key" above when you are subscribed.
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No long-term commitment. Upgrade, downgrade, or cancel anytime. Free Trial includes up to 50 requests.
(Save 2 months with annual billing 🎉)
Trusted by leading companies
The PDF Text Watermark API allows developers to add customizable text watermarks to PDF documents through a simple API request. Upload a PDF file, specify the watermark text, and configure its appearance using options such as position, opacity, font size, color, and rotation. The API processes the document and returns a downloadable version containing the watermark applied across all pages.
Watermarks can be used to identify document status, indicate ownership, display copyright notices, apply company branding, or mark documents for internal and external distribution. Common examples include "CONFIDENTIAL", "DRAFT", "INTERNAL USE ONLY", company names, project identifiers, legal notices, and other custom text labels.
The API supports configurable watermark placement, allowing text to appear in the center of the page or in one of the page corners. Opacity settings can be adjusted to ensure the watermark remains visible while preserving the readability of the original document. Rotation controls make it possible to create diagonal stamps commonly used for confidential and draft documents.
Watermark text is rendered directly into the PDF and supports Unicode characters, making it suitable for multiple languages and international document workflows. Font size and color can be customized to match branding requirements or document policies.
Common use cases include:
Marking confidential documents
Adding draft or review status indicators
Applying company branding to PDFs
Copyright and ownership labeling
Legal and compliance workflows
Contract and agreement management
Internal document distribution
Invoice and report identification
Educational and publishing platforms
Document archiving and record management
Features:
Add text watermarks to PDF documents
Apply watermarks across all pages
Custom watermark text
Adjustable position settings
Configurable opacity levels
Custom font size controls
Custom text color selection
Rotation angle support
Unicode character support
Downloadable PDF output
JSON response format
HTTPS-based API access
The API accepts PDF files as multipart form-data and returns structured JSON containing a download URL for the processed document. It can be integrated into document management systems, workflow automation platforms, web applications, mobile applications, business software, and file processing services that require PDF watermarking functionality.
To obtain your API key, first sign in to your account and navigate to the API you want to use. From the API's Pricing section, choose a plan and complete the subscription process. Once subscribed, return to the API page and you will see your API Access Key displayed at the top of the documentation page. You can use this key to authenticate your requests.
You can’t switch APIs during the free trial. If you subscribe to a different API, your trial will end and the new subscription will start as a paid plan.
The free trial lasts for 7 days and allows you to make up to 50 API requests.
No, the free trial is available only once, so we recommend using it on the API that interests you the most. Most of our APIs offer a free trial, but some may not include this option.
Yes. If the API offers a free trial, you will see a "Free 7-Day Trial" option in its Pricing section. The trial lasts for 7 days and allows up to 50 API requests, enabling you to evaluate the API before subscribing to a paid plan.
Zyla API Hub is like a big store for APIs, where you can find thousands of them all in one place. We also offer dedicated support and real-time monitoring of all APIs. Once you sign up, you can pick and choose which APIs you want to use. Just remember, each API needs its own subscription. But if you subscribe to multiple ones, you'll use the same key for all of them, making things easier for you.
You can monitor your API usage through the response headers included with every request:
x-zyla-api-calls-monthly-used: Shows the total number of API requests you have used during the current billing period.
x-zyla-api-calls-monthly-remaining: Shows the number of API requests you have remaining for the current billing period.
Yes, you can cancel your subscription at any time. Simply go to the Pricing section of the API you're subscribed to and click the "Unsubscribe" button.
Please note that upgrades, downgrades, and cancellations take effect immediately. Once your subscription is canceled, access to the service will end immediately, regardless of any remaining API calls in your quota.
Please have a look at our Refund Policy: https://zylalabs.com/terms#refund