#include <StringConstants.au3> ; to declare the Constants of StringRegExp
#include <Array.au3> ; UDF needed for _ArrayDisplay and _ArrayConcatenate
Local $sRegex = "^([a-zA-Z0-9_=]+)\.([a-zA-Z0-9_=]+)\.([a-zA-Z0-9_\-\+\/=]*)"
Local $sString = "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJncm91cCI6ImFuZHJvaWQiLCJhdWQiOiJhbmRyb2lkIiwiaXNzIjoiYXBpLnNvY2lhbGRlYWwubmwiLCJtZW1iZXIiOnsibmFtZSI6ImVyaWsifSwiZXhwIjoxNDUyMDgzMjA3LCJpYXQiOjE0NTE5OTY4MDd9.u7ZBa9RB8U4QL8eBk4hmsjg8oFW19AHuen12c8CvLMj0IQUsNqeC-vwNQvAINpgBM0bzDf5cotyrUzf55eXch6mzfKMa-OJXguO-lARp4fc40HaBWbfnEvGe7yEgSESkt6gJNuprG51A6f4AJyNlXG_3u7O4bAMwiPZJc3AAU84_JXC7Vlq1X3FMaLVGmZdxzA4TvYZEiTt_KHoA49UgzeZtNXo3YiDq-GgL1eV8Li01fwy-M--xzbp4cPcY89jkPyYxUIJEoITOULr3zXQwRfYVe6i0P28oyu5ZzAwYCajBb2T98zN7sFJarNmtcxSKNfhCPnMVn3wrpxx4_Kd2Pw"
Local $aArray = StringRegExp($sString, $sRegex, $STR_REGEXPARRAYFULLMATCH)
; Present the entire match result
_ArrayDisplay($aArray, "Result")
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