#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?<=clients_field_)(.*)(?=:)"
Local $sString = "{" & @CRLF & _
" "success": true," & @CRLF & _
" "companies" [" & @CRLF & _
" {" & @CRLF & _
" "clients_field_15bb4d92-0a64-4431-b9f6-d16873f808dd": "true"," & @CRLF & _
" "clients_field_4741a6c5-3855-4455-b487-0b38b0038ae6": "info@domain.com"," & @CRLF & _
" "clients_field_78f225e0-1a78-4930-b251-ad2217baeb1b": "2017-07-26"," & @CRLF & _
" "clients_field_e5b4ca25-363e-4421-8198-e446207c4fb0": "2017-07-28"" & @CRLF & _
" }," & @CRLF & _
" {" & @CRLF & _
" "clients_field_15bb4d92-0a64-4431-b9f6-d16873f808dd": "true"," & @CRLF & _
" "clients_field_4741a6c5-3855-4455-b487-0b38b0038ae6": "info@domain.com"," & @CRLF & _
" "clients_field_78f225e0-1a78-4930-b251-ad2217baeb1b": "2017-07-26"," & @CRLF & _
" "clients_field_e5b4ca25-363e-4421-8198-e446207c4fb0": "2017-07-28"" & @CRLF & _
" }" & @CRLF & _
" ]" & @CRLF & _
"}"
Local $sSubst = ""
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm