REST: GET Hoe to pass multiple values for same parameter

We are working with a REST API which is internationally defined Health interoperability standard. To search an item they define to use for AND parameters in the URL with same parameter concatenated with & and for OR one parameter with a comma delimited list, to explain some examples:

To search for a person with name=Ria AND name=Sarah the URL is:


To search for a person with name=Ria OR Sarah the URL is:


This is the same problem as explained here:

The format of & for AND and comma delimited for OR seems to be acceptable practice.

Currently I had to write a C# extension to do this because I could not find a way to tell the OutSystems REST how to do the AND with the same parameter repeated "name=Ria&name=Sarah". THe OR is easy because the comma delimited list is the parameter, so that is not a problem.

How can I achieve this multiple same parameter in OutSystems REST please?

Currently I have found this solution which seems to work, I have to still test all use cases:

I build the string with the & and multiple parameters and pass a {dummy} variable to the REST like this:


Where dummy is a string with value "name=Ria&name=Sarah"

This seems to work, but I have to build the string beforehand in a for loop.

Hi Elize,

Like the Stackoverflow response mentions, this specific use case in REST APIs isn't a defined standard, but more of a convention. For reference, if your problem was reversed and you had to implement this API in Outsystems, you wouldn't be able to distinguish those two values: Outsystems would receive those two cases as "Ria,Sarah" regardless of how you'd use the input.

To my knowledge, Outsystems doesn't have a mechanism to directly map these cases, but like you discovered, you can build the query string yourself and use the separators that the API will acknowledge as AND/OR: you can still take advantage of the low code environment and not rely on an Extension.