Add Text Watermark to Word - Text Watermark API

PDF4me Add Text Watermark to Word enables you to add customizable text watermarks to Word documents with comprehensive styling and positioning control. This API service processes Word files and adds text watermarks with full control over text content, font family, font size, colors, rotation angles, orientation presets, and transparency levels. The API receives Word document content through REST API calls, utilizing Base64 encoding for secure transmission. With support for security labels, branding elements, confidentiality notices, and status markers, this solution is ideal for document security, brand protection, and status indication workflows.

Authenticating Your API Request

To access the PDF4me REST API, every request must include proper authentication credentials. Authentication ensures secure communication and validates your identity as an authorized user of the REST API.

Get your api Key

Key Features

• Text Watermark Support: Professional text watermarks with any custom text content
• Font Customization: Full control over font family, font name, and font size
• Color Options: Named colors, hex codes, RGB values, and 3-digit hex support
• Rotation Control: Custom rotation angles (0-360°) or predefined orientation presets
• Transparency Options: Semi-transparent or fully opaque watermark effects
• Automatic Sizing: Intelligent sizing based on text length and font size
• Document-wide Application: Watermarks applied to all sections and headers
• Behind Text Placement: Watermarks positioned behind document content

REST API Endpoint

The PDF4me REST API uses standard HTTP methods to interact with resources. All text watermark addition operations are performed through a single endpoint:

• Method: POST
• Endpoint: office/ApiV2Word/AddTextWatermark

REST API Parameters

Complete list of parameters for the Add Text Watermark to Word REST API. Parameters are organized by category for better understanding and implementation.

Important: Parameters marked with an asterisk (*) are required and must be provided for the API to function correctly.

Required Parameters

Parameter	Type	Description	Example
document*	Object	Document descriptor. Must include Name (string): output Word file name with .docx extension	{ "Name": "document.docx" }
docContent*	Base64	Word document content encoded in Base64	UEsDBBQABgAIAAAA...
watermarkText*	String	Text to display as watermark. Required - cannot be null, empty, or whitespace only. Examples: "CONFIDENTIAL", "DRAFT", "APPROVED"	CONFIDENTIAL

Optional Parameters

Parameter	Type	Description	Example
fontFamily	String	Font family for watermark text. Common: "Arial", "Calibri", "Times New Roman", "Helvetica". Default: "Arial"	Arial
fontSize	Number (double)	Font size in points (1 to 1000). Default: 72	72
fontColor	String	Text color. Named: "Red", "Blue", "Gray". Hex: "#FF0000", "FF0000". RGB: "RGB(255,0,0)". Default: "#808080"	#FF0000
semiTransparent	Boolean	Transparency. true = opacity 50%, false = 100% (default)	true
rotation	Number (double)	Custom rotation angle (0-360°). Default: 0	45
fontName	String	Font name for watermark text	Arial
orientation	String	Predefined orientation: Horizontal (0°), Vertical (90°), Diagonal (45°), Upside-Down (180°). Overrides rotation if provided	Diagonal
cultureName	String	Culture code (e.g., "en-US", "de-DE", "fr-FR"). Default: null	en-US

Text Orientation Options

The watermark text orientation follows this parameter priority:

1. orientation - If provided, uses predefined orientation angle
2. rotation - If orientation not provided, uses custom rotation angle
3. Default - If neither provided, uses 0° (horizontal)

Predefined Orientations:

• Horizontal: 0° (default)
• Vertical: 90°
• Diagonal: 45°
• Upside-Down: 180°

Output

The PDF4me Add Text Watermark to Word REST API returns a JSON response (ApiV2WordApiCallRes). On success the API returns the Word document as a Base64-encoded string in the document field, not as binary data.

Success Response

Success Response

Status Code: 200 OK

Content-Type: application/json

Response Body:

{
  "document": "UEsDBBQABgAIAAAAIQDfpNJsWgEAACAFAAATAAgCW0NvbnRlbnRfVHlwZXNdLnhtbCCiBAIooAAC...",
  "fileName": "document.docx",
  "success": true,
  "errorMessage": null
}

Response Fields:

• document (string): The Word document with text watermark applied, encoded as Base64
• fileName (string): The output Word file name
• success (boolean): Whether the operation succeeded
• errorMessage (string): Error message if success is false; otherwise null

How to Use:

1. Check success; if true, extract the document field from the JSON response
2. Decode the Base64 string to get the binary Word document data
3. Save or process the Word file using fileName

Example (JavaScript):

const response = await fetch(url, options);
const data = await response.json();
if (!data.success) throw new Error(data.errorMessage);
const wordBytes = atob(data.document);
// Save or process wordBytes

Error Responses

Error Responses

The API returns standard HTTP error codes with error details:

400 Bad Request

• Invalid request parameters
• Missing required fields (document, docContent, watermarkText)
• watermarkText cannot be null, empty, or whitespace only
• Invalid Base64 encoding in docContent
• Invalid or corrupted Word document
• Invalid font size (must be between 1-1000)
• Invalid rotation angle

401 Unauthorized

• Invalid or missing API key
• API key not properly Base64 encoded in Authorization header
• Missing Authorization: Basic header

500 Internal Server Error

• Server-side processing error
• Word document processing failure
• Text watermark addition failure

Error Response Format:

{
  "error": "Error message describing what went wrong"
}

Response Format Details

Response Format Details

Important: The API always returns JSON, never binary Word data directly.

Response Structure (ApiV2WordApiCallRes):

{
  "document": "string",     // Base64-encoded Word document content
  "fileName": "string",     // Output Word filename
  "success": true,
  "errorMessage": null
}

Content-Type Header:

• Success: application/json
• The Word document is embedded as a Base64 string within the JSON response

Why Base64?

• JSON-safe encoding for binary data
• Easy to transmit over HTTP
• Compatible with all programming languages
• Can be directly embedded in JSON without escaping issues

Decoding Base64 to Word Document:

JavaScript/Node.js:

const base64 = response.document;
const binary = atob(base64); // Browser
// OR
const binary = Buffer.from(base64, 'base64'); // Node.js

Python:

import base64
word_bytes = base64.b64decode(response['document'])
with open('output.docx', 'wb') as f:
    f.write(word_bytes)

C#:

byte[] wordBytes = Convert.FromBase64String(response.document);
File.WriteAllBytes(response.fileName, wordBytes);

Request Example

Header

Content-Type: application/json
Authorization: Basic YOUR_BASE64_ENCODED_API_KEY

Note:

• Get your API key from the PDF4me Dashboard
• The API key must be Base64 encoded and prefixed with "Basic " in the Authorization header
• Example: If your API key is abc123, encode it to Base64 and use Authorization: Basic YWJjMTIz

Payload

Basic Example (Required Fields Only):

{
  "document": { "Name": "document.docx" },
  "docContent": "UEsDBBQABgAIAAAAIQDfpNJsWgEAACAFAAATAAgCW0NvbnRlbnRfVHlwZXNdLnhtbCCiBAIooAAC...",
  "watermarkText": "CONFIDENTIAL"
}

Advanced Example (With Optional Fields):

{
  "document": { "Name": "document.docx" },
  "docContent": "UEsDBBQABgAIAAAAIQDfpNJsWgEAACAFAAATAAgCW0NvbnRlbnRfVHlwZXNdLnhtbCCiBAIooAAC...",
  "watermarkText": "CONFIDENTIAL",
  "orientation": "Diagonal",
  "fontFamily": "Arial",
  "fontSize": 72,
  "fontColor": "#FF0000",
  "semiTransparent": true,
  "cultureName": "en-US"
}

Custom Rotation Example:

{
  "document": { "Name": "document.docx" },
  "docContent": "UEsDBBQABgAIAAAAIQDfpNJsWgEAACAFAAATAAgCW0NvbnRlbnRfVHlwZXNdLnhtbCCiBAIooAAC...",
  "watermarkText": "DRAFT",
  "fontFamily": "Times New Roman",
  "fontSize": 48,
  "fontColor": "Gray",
  "rotation": 45,
  "semiTransparent": true
}

Code Samples

The PDF4me Add Text Watermark to Word REST API provides code samples in multiple programming languages. Choose the language that best fits your development environment:

C#

C# (CSharp) Sample

Complete C# implementation for adding text watermarks to Word documents:

View C# Sample

Java

Java Sample

Java implementation with full error handling and response processing:

View Java Sample

JavaScript

JavaScript Sample

Node.js and browser-compatible JavaScript implementation:

View JavaScript Sample

Python

Python Sample

Python implementation with requests library and JSON handling:

View Python Sample

Salesforce

Salesforce Sample

Salesforce Apex implementation for CRM integration:

View Salesforce Sample

n8n

n8n Sample

n8n workflow implementation for automation:

View n8n Sample

Google Script

Google Script Sample

Google Apps Script implementation for Google Workspace integration:

View Google Script Sample

AWS Lambda

AWS Lambda Sample

Serverless AWS Lambda function implementation:

View AWS Lambda Sample

Industry Use Cases & Applications

Legal & Professional Services

Legal & Professional Services Use Cases

• Confidential Documents: Watermark legal documents with "CONFIDENTIAL" notices
• Draft Contracts: Mark draft agreements with "DRAFT - UNDER REVIEW" status
• Privilege Labels: Apply "ATTORNEY-CLIENT PRIVILEGE" text watermarks
• Status Markers: Indicate "APPROVED" or "PENDING REVIEW" status

Business & Enterprise

Business & Enterprise Use Cases

• Pricing Sheets: Add "CONFIDENTIAL PRICING" text watermarks to rate cards
• Proposals: Watermark client proposals with "© 2024 [Company]" notices
• Internal Reports: Mark internal analytics with "INTERNAL USE ONLY"
• Draft Materials: Indicate "DRAFT - NOT FOR DISTRIBUTION" status

Education & Research

Education & Research Use Cases

• Patient Data: Add "HIPAA PROTECTED" text watermarks to patient records
• Medical Reports: Watermark lab results with "CONFIDENTIAL MEDICAL" notices
• Research Data: Apply "RESEARCH DATA - CONFIDENTIAL" text watermarks
• Insurance Claims: Mark insurance documents with "PRIVACY PROTECTED" labels

Finance & Banking

Finance & Banking Use Cases

• Financial Statement Security: Add "CONFIDENTIAL" text watermarks to financial reports
• Draft Budgets: Watermark draft budget documents with "DRAFT" status
• Audit Documents: Apply "AUDIT COPY" text watermarks to audit deliverables
• Client Reports: Add "© 2024 [Company]" text watermarks to client-facing reports

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