How to maintain sequence of the values in a JSON object?

Question

I am working on an ionic app which will be used on Android and iOS platforms. I am using one endpoint to post user data to the backend.

{
  "name": "abcd",
  "emailAddress": "[email protected]",
  "mobile": "1234567890"
}

when I send this JSON Object as above from ionic native HTTP it receives at backed like

{
      "name": "abcd",
      "mobile": "1234567890",
      "emailAddress": "[email protected]"

    }

as I am creating authorization signature using this information it causing an issue of unauthorized as the signature does not match at the backend. Is there any way to maintain the sequence of the JSON object? need some help here thanks!!