Hi @Bob_S 

This is using Workflow O365 but I believe it should work for you.

String: <Your source JSON>

REPLACE Operation

Pattern: ({"access_token":")(.*)(","ex)(.*})

Replacement String: $2

Output: <Your output variable>

Result Output (using Log to History)

Hope that helps

Hi Bob, have you found a solution for this? I also just got the same task of extracting an access_token from json on Nintex for SharePoint on prem.

Yeah my problem got solved. Are you facing the exact same issue? Or do you need to extract from a different json?

My json is in a different order but the content is (nearly) the same.

Look at the solution given above, that worked for me! Or send an example of your json so I can take a look at it.

My json looks like this (access_token shortened for readability):

{"token_type":"Bearer","expires_in":3599,"ext_expires_in":3599,"access_token":"I6Il9BM2d5bE.eyJhdMMjLTW0_QDjv-7eTK0-uC3hb-JcCMBCag"}

Can you put in this:

Pattern: ({*.)(.*)("access_token":")(.*)(.*"})

Replacement string: $4 

Thank you, Bob. This works for me.