Watermark Tools
Text Watermark PDF C# Overview
Add professional text watermarks to PDF pages with granular styling and placement controls. Choose the text and font family, embed or subset fonts, set size, fill and stroke colors with stroke width, and pick the rendering mode. Adjust opacity and rotation, position the watermark within page or crop box, and target specific pages or ranges. Optionally attach a link or a go‑to page action and preserve or update PDF metadata as needed. Designed for automation, the C# library produces consistent, branded results across batches without manual editing.
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Process and convert files in seconds with our high-performance cloud infrastructure.
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Our advanced algorithms ensure pixel-perfect and content-accurate file conversions.
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ISO 27001, HIPAA, and GDPR compliant with encrypted file processing.
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Developer Friendly
Comprehensive SDKs and clear documentation for quick and simple integration.
Time-Saving Automation
Automate repetitive document workflows and focus on what matters most.
Customizable Parameters
Fine-tune your automation with these powerful conversion options
File
File Supported formats: .pdfFile to be converted. Value can be URL or file content.
Password
StringSets the password to open protected documents.
PageRange
String Default: 1-2000Set page range. Example 1-10 or 1,2,5.
Text
StringSpecifies the text to use as watermark. The list of supported variables:
%PAGE%- current page number%PAGES%- total number of pages%FILENAME%- name of the file%WEEKDAY%- full weekday name%WEEKDAY_SHORT%- abbreviated weekday name%MONTH%- month number (1-12)%MONTHNAME%- full month name%MONTHNAME_SHORT%- abbreviated month name%YEAR%- year with century (YYYY)%YEAR_SHORT%- year without century (YY)%DAY%- day of month%DAY_YEAR%- day of the year (1 -366)%HOUR%- hour (01- 12)%HOURS%- hour (00-23)%MINUTES%- minutes (00-59)%SECONDS%- seconds (00-59)%AMPM%- AM PM%DATE%- local date representation%TIME%- local time representation%DATETIME%- local date and time%AUTHOR%- document Author%TITLE%- document Title%SUBJECT%- document Subject%KEYWORDS%- document Keywords%N%- new line
Style
Collection Default: stampSpecifies watermark style, stamp or watermark. The stamp is placed over page content and watermark under page content.
Values: stamp watermarkFontSize
Integer Default: 40Specifies the watermark font size.
Range: 1 .. 200TextRenderingMode
Collection Default: fillstrokeSpecifies the text rendering mode.
Values: filltext stroketext fillstroke invisibleFontColor
ColorSpecifies the watermark font color.
StrokeColor
ColorSpecifies font stroke color.
StrokeWidth
Integer Default: 1Specifies the stroke width.
Range: 0 .. 200FontName
Collection Default: arialSpecifies the watermark font name. Contact us if you are looking for a specific font for a watermark that is missing from the list.
Values: arial bahnschrift calibri cambria consolas constantia courierNew georgia tahoma timesNewRoman verdanaRotate
Integer Default: 0Specifies the watermark rotation angle in degrees.
Range: 0 .. 360Opacity
Integer Default: 100Specifies watermark opacity level.
Range: 0 .. 100GoToLink
StringSpecifies the web address to go when the watermark is clicked.
GoToPage
StringSpecifies the page number to go when the watermark is clicked.
LineSpacing
Integer Default: 0Specifies the watermark text line spacing.
Range: -30 .. 30PageBox
Collection Default: mediaboxSpecifies the PDF page box used as the reference area for applying the watermark.
Values: mediabox trimbox bleedbox cropboxHorizontalAlignment
Collection Default: centerSpecifies the horizontal watermark alignment.
Values: left center rightVerticalAlignment
Collection Default: centerSpecifies the vertical watermark alignment.
Values: top center bottomMeasurementUnit
Collection Default: ptMeasurement unit for position and size parameters.
Values: pt in mm cmOffsetX
DoubleSpecifies the watermark offset along the X-axis. Positive values move the watermark to the right, while negative values move it to the left, using the selected MeasurementUnit.
OffsetY
DoubleSpecifies the watermark offset along the Y-axis. Positive values move the watermark downward, while negative values move it upward, using the selected MeasurementUnit.
Width
Double Default: 0Specifies the width of the watermark text box in the selected MeasurementUnit. A value of 0 means the width is unspecified.
Height
Double Default: 0Specifies the height of the watermark text box in the selected MeasurementUnit. A value of 0 means the height is unspecified.
FontEmbed
Bool Default: TrueSpecifies whether fonts should be embedded.
FontSubset
Bool Default: TrueSpecifies whether fonts should be subset.
StoreFile
Bool Default: FalseWhen the StoreFile parameter is set to True, your converted file is written to ConvertAPI’s encrypted, temporary storage and made available via a time-limited secure download URL, valid for up to 3 hours. After this period, the file is permanently deleted.
When StoreFile is set to False, conversion happens entirely in-memory. The raw file bytes are streamed back in the API response without touching disk or external storage, ensuring maximum security and zero persistence so that only you can access the content.
Step-by-Step Guide
Easy Text Watermark PDF integration programmatically using our simple C# SDK
1. C# library install
ConvertAPI provides an ASP.NET C# library that allows you to perform a Text Watermark PDF conversion with just a few lines of code. Convert PDF to TEXT-WATERMARK using C# programming language with no effort at all!
NuGet Terminal >
Install-Package ConvertApi
2. Authenticate ConvertAPI C# library
You can obtain your API Token by signing up for a free account. Once you sign up, you'll receive 250 free conversions instantly! Grab your authentication key from the account dashboard, and authenticate the ConvertAPI C# library like this:
// get your API Token here: https://www.convertapi.com/a/auth
ConvertApi convertApi = new ConvertApi("api_token");
3. Text Watermark PDF using C# .NET
Once you have your authentication in place, simply copy-paste this Text Watermark PDF conversion code snippet into your C# project:
Integrate within minutes
Easy Text Watermark PDF automation using our simple C# SDK
Compatible With All .NET Frameworks & Tools
Frequently Asked Questions
What is ConvertAPI C# SDK?
The ConvertAPI C# SDK is a lightweight, easy-to-use library for .NET developers to integrate document and file conversions into their applications with minimal code. It connects directly to the ConvertAPI REST service, allowing you to automate file conversions, merging, splitting, and more.
What types of conversions are supported?
ConvertAPI offers 300+ converters and tools, including DOCX to PDF, XLSX to PDF, PDF to JPG, HTML to PDF, image processing, metadata extraction, compression, and advanced document workflows. You can automate complex document processing scenarios within your .NET applications using the SDK.
Can I build complex conversion workflows using the SDK?
Yes, the ConvertAPI .NET C# SDK allows you to chain conversions, merge documents, extract pages, and apply advanced parameters to automate end-to-end document workflows within your applications.
Is there a file size limit when using ConvertAPI?
The maximum file size you can convert depends on your ConvertAPI plan type. Higher-tier plans allow larger files and increased concurrency for high-volume document processing needs.
Can I convert files entirely in memory without storing them on your servers?
Yes, ConvertAPI supports in-memory conversions, allowing you to send and receive files as streams without saving them to disk on ConvertAPI servers. This enables secure, diskless workflows for sensitive or temporary files.
Which .NET versions does the ConvertAPI SDK support?
The SDK supports .NET Framework 4.5+, .NET Core, .NET 5, 6, 7, and 8, ensuring compatibility across your existing and new projects.
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"ConvertAPI is a reliable, cost-effective solution with a proven track record of stability. It has grown significantly in maturity, adopting enterprise-grade practices over the years."
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