The GroupDocs.Annotation Cloud is a REST API and universal document annotator that supports almost all common business document and image file formats. It gives developers an API for creating advanced online document annotation tools. With GroupDocs.Annotation Cloud API developers can deliver advanced annotation features to their users quickly. It provides features for export/import annotations into/from files, additionally to possibility to save files in supported formats.

Supported Formats

  • Microsoft Word: DOC, DOCM, DOCX, DOT, DOTM, DOTX
  • OpenDocument Formats: ODT, OTT, ODP, OTP
  • Rich Text Format: RTF
  • Plain Text Format: TXT
  • Microsoft Excel: XLS, XLSX
  • Microsoft Powerpoint: PPT, PPTX, PPSX
  • Portable Document Format: PDF
  • Microsoft Visio: VSSX, VSS, VSSM, VDX, VSD, VSDX, VSDM, VSTM, VSX, VTX
  • Image Files: BMP, PNG, JPG, JPEG, TIFF, TIF, GIF
  • Microsoft Outlook: EML, EMLX, MSG
  • HyperText Markup Language: MHTML

Security and Authentication

The GroupDocs.Annotation Cloud API is secured and requires authentication. Developers can create an app access key ID (appSID) and app secret access key when they register. Authenticated requests require a signature and AppSID query parameters or OAuth 2.0 authorization header. You can see complete detail here.


GroupDocs.Annotation Cloud comes with SDKs for different platforms to use this REST API in your specific project effortlessly. Checkout our GitHub repository for a complete list of GroupDocs.Annotation SDKs along with working examples, to get you started in no time.

API Explorer

The easiest way to try out our API right away in your browser! With the GroupDocs for Cloud Web API explorer. This is a collection of Swagger documentation for the GroupDocs for Cloud APIs. You can get information about all the resources in the API. It also provides testing and interactivity to our API endpoint documentation.