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The URL Rewrite object defines friendly URLs, intended to improve the usability and accessibility of a website. 

It lets you define URLs and the corresponding mapping to objects with their parameters.

Defining friendly URLs lets you separate the interface from the implementation:

  • It helps you to make it SEO friendly
  • The defined URLs are independent of the object names and their modularization in the KB
  • The defined URLs are independent of the chosen generator, a feature that adds flexibility and reduces lock-in to a specific platform (.NET, .NET Core or Java).

The object has several parts: 

  • Rewrite Rules
  • Variables
  • Help
  • Documentation

Rewrite Rules

This is the main part of a URL Rewrite Object, as it lets you define the mappings (also called rewrite rules).

Each mapping consists of a part on the left where the URL (or part of it) is specified, and on the right side, the object and its parameters are referenced. Mappings are separated by a semicolon.

home                                 => Home; 

core/clients                        => Core.WWClient;
core/clients/{&ClientId}/{&Mode}    => Core.Client(&Mode,&ClientId);
core/clients/{&ClientId}            => Core.ViewClient(&ClientId);

The above mappings result in URLs like the following:



  • You do not need to reference all the parameters
  • Creating a URL Rewrite object changes the behavior of the Link Function. Instead of returning document-relative URLs, it returns server-relative URLs when a URL Rewrite object exists. This can introduce breaking changes in your code; for example, if you concatenate the resulting string with another to create an absolute URL.
  • API object is not supported.


To use this feature, some restrictions apply


1) Partial parameter references

Missing parameters will be added to the query string:

core/clients/{&ClientId}    => Core.Client(&Mode,&ClientId);

This results in:


when the object is called as follows:


2) Object mapping without parameter mapping

You can write

core/client => Core.Client;

even if the object Core.Client has a


In this sample, when the parameter style is positional, the resulting URL would be as follows:


when the object is called as follows:



GeneXus automatically deploys all the rules defined in the URL Rewrite objects of the KB when deploying a Deployment Unit object. This implies that there must be no conflict among rules defined in different objects.


When deploying to Tomcat 8 or higher, rewrite rules work automatically; however, when you deploy to another Servlet Server, you may need to make extra configurations. For that, take the rules from the urlrewrite.config file to configure the server.


Generators: .NET, .NET Core, Java

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