Watermark PDF API & SDK

Secure Document Control with Programmable Overlays

Professional Document Protection & Branding Through Code

The Watermark PDF API provides development teams with a robust solution for programmatically adding customizable watermarks to PDF documents. This RESTful API enables software vendors, automation engineers, and development teams to seamlessly integrate watermarking capabilities into their applications, services, and document workflows.

Our API handles the technical complexity of PDF watermarking while giving you granular control over every aspect of the process. Whether you need to apply confidentiality notices across corporate documents, stamp logos on client-facing materials, or mark document status (DRAFT, FINAL, etc.), our solution delivers pixel-perfect results with minimal implementation effort.

Unlike generic PDF libraries that require extensive configuration or cloud-based solutions with limited customization, our Watermark PDF API offers enterprise-grade performance with a straightforward integration path, supporting both high-volume batch processing and on-demand watermarking operations.

Key Technical Features & Capabilities

Comprehensive Watermark Customization

Our API provides extensive control over watermark appearance and placement. Set precise font properties (family, size, color, weight, style), adjust opacity from 0-1, and position watermarks with pixel-perfect accuracy. The API supports multiple rotation angles (0°, 45°, 90°, 270°, 315°) and nine distinct positioning options (center, top, rightTop, right, rightBottom, bottom, leftBottom, left, leftTop), giving you complete control over watermark presentation without requiring deep PDF structure knowledge.

Dual Watermark Types Support

Apply either text-based or image-based watermarks according to your requirements. Text watermarks support full typographic control with customizable font properties, while image watermarks accept multiple formats (PDF, JPG, JPEG, BMP, PNG, GIF, WWF, TIF, TIFF) with scaling options ranging from 1% to 500%. This flexibility enables both simple text stamps and complex visual watermarks like logos or signatures without additional image processing code.

Selective Page Processing

Target specific pages or page ranges with precision using intuitive page selection syntax. The API accepts comma-separated page numbers and dash-notated ranges (e.g., "1,3,5-7"), allowing you to apply watermarks only where needed. This capability is particularly valuable for documents with distinct sections requiring different watermark treatments, such as appendices, cover pages, or specific content areas.

Layer Control & Transparency Management

Position watermarks either above or behind existing content with the isBehind parameter. When placed above, watermarks overlay existing content; when behind, they appear as background elements. Combined with opacity control (0-1 scale), this provides sophisticated visual integration options. For example, set opacity to 0.3 for subtle background branding or 1.0 for prominent confidentiality notices.

Password-Protected Document Support

Process secured PDFs by providing the document password in your API request. This feature maintains security throughout the watermarking workflow and eliminates the need for separate decryption/encryption steps in your application logic. The API handles authentication transparently, preserving all existing document security while adding watermarks.

Asynchronous Processing Architecture

Built for reliable performance with documents of varying sizes, the API implements an asynchronous processing model. Operations return an ID immediately, allowing you to check status and retrieve results when processing completes. This architecture prevents connection timeouts with large files and enables efficient integration with event-driven applications.

POST/add-watermark-to-pdf/v1
Content-Type:multipart/form-data

// Request body parameters
file: [binary PDF file]
text: "CONFIDENTIAL"
position: "center"
opacity: 0.5
rotation: "45"

Simple File Handling

Upload PDF files directly from local storage, cloud services (Google Drive, Dropbox), or via drag-and-drop interfaces. The API accepts files up to 10MB, supporting most business document sizes. After processing, retrieve watermarked documents programmatically or save them to your preferred storage location for immediate use in downstream workflows.

Extensive Image Format Support

When using image watermarks, the API supports a wide range of formats beyond just JPG and PNG. Accept PDF, BMP, GIF, WWF, TIF, and TIFF files as watermark sources, allowing users to implement complex visual watermarks without format conversion. The API also supports extracting specific pages from multi-page source PDFs as watermarks.

Technical Implementation Advantages

RESTful API vs. Traditional Libraries

Our Watermark PDF API offers significant advantages over traditional PDF processing libraries:

Feature
Implementation Time
Watermark PDF API
Minutes with direct HTTP calls
Traditional Libraries
Hours/days of integration work
Feature
Server Resources
Watermark PDF API
Offloaded processing
Traditional Libraries
Local CPU/memory consumption
Feature
Maintenance
Watermark PDF API
Automatic updates
Traditional Libraries
Manual dependency management
Feature
Cross-Platform
Watermark PDF API
Any language with HTTP support
Traditional Libraries
Language/platform specific
Feature
Scalability
Watermark PDF API
Built-in
Traditional Libraries
Custom implementation required

The API approach eliminates dependency conflicts, version management headaches, and platform compatibility issues while providing consistent results across all client applications.

SDK Integration Options

For developers requiring deeper integration, our complementary SDK provides:

Native language bindings for major programming environments

Offline processing capabilities for air-gapped environments

Advanced event handling and progress monitoring

Integrated error recovery mechanisms

Consistent API surface across deployment models

The SDK maintains the same parameter structure as the REST API, allowing seamless transitions between cloud and on-premises implementations as requirements evolve.

Advanced Document Control

Beyond simple watermarking, our solution provides a foundation for comprehensive document control:

Apply watermarks conditionally based on document content or metadata

Implement dynamic watermarks containing timestamps, user information, or tracking codes

Create multi-layer watermarks combining text and images

Process documents in automated workflows without user intervention

Apply watermarks to odd/even pages separately using the subset option

This flexibility supports sophisticated document management requirements without custom PDF manipulation code.

Technical Implementation

The Watermark PDF API follows standard REST conventions with a straightforward integration path:

  • Authentication

    Obtain your API key from the developer portal

  • Result Retrieval

    Download the watermarked document

  • Request Formation

    Construct a multipart/form-data POST request to /add-watermark-to-pdf/v1

  • Response Handling

    Receive operation ID and check status until completion

  • Parameter Configuration

    Set watermark properties via request parameters

The API returns a 202 Accepted response with an operation ID for asynchronous processing:

{
"id":"3fa85f64-5717-4562-b3fc-2c963f66afa6"
}

Use this ID with /operation/v1/{operationId}/status to monitor progress and retrieve results when processing completes

Layer Control & Advanced Techniques

The Watermark PDF API offers sophisticated control over how watermarks interact with document content:
Above Page Watermarks: Set isBehind: false to place watermarks on top of existing content, making them immediately visible but potentially obscuring important information
Behind Page Watermarks: Set isBehind: true to place watermarks behind existing content, allowing text and images to remain unobstructed while still providing visible marking
Layered Watermarking: Apply multiple watermarks in sequence to create complex composite effects, such as a background logo with overlaid text

These capabilities enable advanced document marking techniques previously requiring specialized desktop publishing software.

Start Implementing PDF Watermarking Today

Our Watermark PDF API provides a powerful yet straightforward solution for adding professional watermarking capabilities to your applications and workflows. With comprehensive customization options, flexible deployment models, and simple integration paths, you can implement robust document protection and branding features without extensive PDF expertise.