Document and image annotation solution for any platform.

GroupDocs.Annotation Cloud API is a platform independent Document and Image Annotation Solution, that empowers the developers to add an annotation feature in their application with minimum efforts. The API supports a range of Annotation types, but in this post I will focus on the Text Redaction Annotation to demonstrate how to redact PDF text.

Text Redaction is a process to remove content from a document permanently. Before you publish the document, you need to remove sensitive and private data from the document. GroupDocs.Annotation Cloud provides, the Text Redaction Annotation to redact the text on the certain page region. Text redaction fills part of text with a black rectangle, to hide underlying word or phrase.

Let me give you a quick overview of how to redact text with GroupDocs.Annotation Cloud with a simple set of HTTP requests. I will be using cURL to redact text in a PDF document in this example. The API is not limited to PDF file format, you can check the complete list of supported file formats. It also provides SDKs for all popular programming languages. You can check the available SDKs from GitHub repository with working examples and use directly in your application.

We will follow these steps to find the duplicate images:

  • Generate access token for authentication
  • Upload source document to storage
  • Add Annotation to document
  • Download annotated document

Generate Access Token

Upload source document to storage

Annotate source document

The SvgPath property is used to add the text redaction annotation and coordinates of SvgPath property start from bottom of the document page and increase to the top.

Download Annotated document

If you’ve not already tried our REST API, we encourage you to head over to GroupDocs.Annotation Cloud with a free trial today. All you need is to sign up with the Once you’ve signed up, you may go through the following useful resources of GroupDocs.Annotation Cloud.


Your feedback is very important for us. If you’ve any suggestions or if you need any particular features which you expect our REST API to have, please feel free to drop us a comment below or at the support forum.