Digitally Sign Documents via cURL APIs

cURL Signature REST APIs to apply, verify & search eSignatures in various file formats. Supports diverse varieties of electronic signatures.

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Electronic Signature REST API

GroupDocs.Signature Cloud for cURL


cURL is a free client-side URL transfer library that allows you to handle HTTP requests and responses in dealing with the GroupDocs.Signature Cloud REST API. The API allows you to create, verify and search different type of signature objects in a number of document formats. It provides a wide variety of signature options like putting signatures on a document, verify document and search signatures in it. The API supports HTTP requests and get responses in form of JSON or XML data. Hence, any language or platform which supports the HTTP requests and responses is capable of running the API.


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Advanced Document Signature REST API Features



Provide list of supported document formats


Retrieve document pages information


Retrieve document properties


Verify Text and Digital signatures


Verify Barcode and QR-Code signatures


Cross-Platform Compatibility

Get Started with Document Signing REST API

It is easy to get started with GroupDocs.Signature Cloud as there is nothing to install. Simply create an account at GroupDocs Cloud and get your application information. Once you have the App SID & key, you are ready to give theGroupDocs.Signature Cloud REST API a try with any language - on any platform. Our e-Signing API for cloud allows you to e-sign a variety of documents with well-structured API calls.

Supported Signature Types

Our e-Signature RESTful API supports the following signature types:

  • Text Signature
  • Image Signature
  • Barcode Signature
  • QR-Code Signature
  • Digital Signature
  • Stamp Signature

The API has flexible methods to add supported signatures to a number of supported document formats. For instance, the API provides methods to create Text Signature in Document Pages with different options of Text, location, alignment, font, margins and appearances by using Signature Options Object data in request body. Below mentioned example shows how to add text signatures to a PDF document with just a few lines of code.

Add Text Signature to a PDF Document - cURL

curl -v "" \
-H "Content-Type: application/json" \
-H "Accept: application/json" \
-d "{"Margin": {"All": 0,"Left": 0,"Top": 0,"Right": 0,"Bottom": 0},"SheetNumber": 1,"RowNumber": 11,"ColumnNumber": 22,"BorderVisiblity": true,"BorderDashStyle": 5,"BorderTransparency": 0.0,"BorderWeight": 1.0,"BackgroundTransparency": 0.1,"SignatureImplementation": "TextStamp","Text": "John Smith","Width": 100,"Height": 100,"LocationMeasureType": "Pixels","SizeMeasureType": "Pixels","RotationAngle": 0,"HorizontalAlignment": "Right","VerticalAlignment": "Center","MarginMeasureType": "Pixels","SignAllPages": false,"Font": {"FontFamily": "Times New Roman","FontSize": 14.0,"Bold": false,"Italic": false,"Underline": false},"ForeColor": {"Web": "Black"},"BorderColor": {"Web": "Black"},"BackgroundColor": {"Web": "OrangeRed"},"OptionsType": "WordsSignTextOptionsData"}" \
-H "authorization: Bearer xxxxxxxx"

Cloud based e-Signing API Features

GroupDocs.Signature Cloud REST APIs allow the following operations with documents:

  • Provide list of supported document formats
  • Obtain list of supported Barcode encode type names
  • Obtain list of supported QR-Code encode type names
  • Retrieve document properties like document size, creation and update dates, count of pages etc
  • Retrieve document pages information like pages count, size of each page etc
  • Support adding all Signature types for Pdf documents
  • Support working with all Signature types (except Digital Signature for Slides) on Microsoft Document formats like Words, Cells, Slides
  • Verify Text and Digital signatures for Pdf, Words and Cells document types
  • Verify Barcode and QR-Code Signatures for all document format types

Flexible Deployment Options

Our RESTful electronic signature API is easy to understand, clearly documented and comes with SDKs and live examples for all major languages. For developers who prefer on-premises deployment, we also offer downloadable .NET and Java APIs.

Extensive File Type Support

GroupDocs.Signature allows end users to sign documents literally in all common business formats, including PDF, Microsoft Word, Excel, PowerPoint, Rich Text format etc. 

Cross-Platform Compatibility

Being a RESTful API, GroupDocs.Signature Cloud can be used with any language or platform which supports HTTP requests and responses. You can also use GroupDocs.Signature Cloud with many third party storage providers including Amazon S3, Google Cloud, Google Drive and DropBox.

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