Example of VB/VBA license key validation using https://keygen.sh and Visual Basic. If you're using this to add licensing an Excel document, you may need to activate "Microsoft Scripting Runtime" in Excel under "Tools" and then "References." See this tutorial on making HTTP requests from within Excel: http://excelerator.solutions/2017/08/28/excel…

keygen.vb

' Call this function from a dialog that prompts for the customer's
' license key, or however you prefer. Call as often as needed.
Function ValidateLicenseKey(licenseKey As String)
  ' TODO: Update this to your Keygen account ID
  Dim accountId As String
      accountId = "demo"

  Dim req As Object
      req = CreateObject("MSXML2.XMLHTTP")
    With req
        .Open "POST", "https://api.keygen.sh/v1/accounts/" & accountId & "/licenses/actions/validate-key", False
        .setRequestHeader "Content-Type", "application/json"
        .send "{ ""meta"": { ""key"": """ & licenseKey & """ } }"
    End With

  Dim res As String
      res = req.ResponseText

  Dim json As Dictionary
      json = JsonConverter.ParseJson(res)

  If json.Exists("errors") = True Then
    ' TODO: Handle fatal HTTP error (no internet access, etc.)
  End If

  Dim meta As Dictionary
      meta = json.Item("meta")

  If meta.Item("valid") = True Then
    ' TODO: Handle valid license key (possibly do nothing)
  Else
    ' TODO: Handle invalid license key
  End If
End Function