How to capture the repsonse from POST URL and update a field in CRM module?

How to capture the repsonse from POST URL and update a field in CRM module?

Hi,

I have defined a custom function which gets executed for every record creation in a module. The custom function takes contact name, email id as input and creates a user in an external application.

Here I would like to how to read response object returned by POST URL? At the same time the function return type is void. How can I read the response which is in json format and update a field in the module with the response key values.

Please suggest.

Thanks
Krishna