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Contents Summary

You can use GroupDocs.Annotation without the license. The usage and functionalities are pretty much same as the licensed one but you will face few limitations while using the non-licensed API.

Evaluation Limitations

Following are the limitations user will face while using trial version of the GroupDocs.Annotation API:

  • Only up to 2 first pages of document are processed.
  • Only 15 document views per hour.
  • Only first 3 annotations are saved permanently.
  • PDF documents: document should not have more then four elements of any collection
  • Aspose trial badges are placed in the document on the top of each page.


The license file contains details such as the product name, number of developers it is licensed to, subscription expiry date and so on. It contains digital signature, so user is not allowed to modify the file. Even inadvertent addition of an extra line break into the file will invalidate it. You need to apply license before utilizing GroupDocs.Annotation API in order to avoid evaluation limitations. However, license can be applied from file or stream. The easiest way to set a license, is to put the license file in the root directory or place it anywhere and store the path in a String.


Calling License.SetLicense multiple times is not harmful but it wastes processor time. If you are developing a Windows Forms or console application, call License.SetLicense in your startup code, before using GroupDocs.Annotation classes. 

When developing an ASP.NET application, you can call License.SetLicense from the Global.asax.cs (Global.asax.vb) file in the Application_Start protected method. It is called once when the application starts. Do not call License.SetLicense from within Page_Load methods since it means the license will be loaded every time a web page is loaded.

Applying a License from Disk

Code below will explain how to apply product license.

Applying a License from Stream

Code below will explain how to apply product license.

Applying Metered License

You can also set Metered license as an alternative to license file. It is a new licensing mechanism that will be used along with existing licensing method. It is useful for the customers who want to be billed based on the usage of the API features. For more details, please refer to Metered Licensing FAQ section.

Following is the sample code demonstrating how to set metered public and private keys.

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