This example shows how to fetch whois with a given mail address from the SecurityTrails domain API

SecurityTrails WHOIS API.json

curl -s \
     --request POST \
     --header "Content-Type: application/json" \
     --header "APIKEY: $ST_API" \
     --data-binary "{
  \"filter\": {
    \"whois_email\": \"chris@ueland.com\"
  }
}" \
'https://api.securitytrails.com/v1/search/list/' | jq -C
{
  "records": [
    {
      "whois": {
        "registrar": "GoDaddy.com, LLC",
        "expiresDate": 1510068206000,
        "createdDate": 1383837806000
      },
      "mail_provider": [
        "Atlantic.net, Inc."
      ],
      "hostname": "servermom.org",
      "host_provider": [
        "Rackspace Ltd."
      ],
      "alexa_rank": 206147
    },
    { 
      "snipped": "-------------"
    },
    {
      "whois": {
        "registrar": "GoDaddy.com, LLC (R91-LROR)",
        "expiresDate": 1371325092000,
        "createdDate": 1245094692000
      },
      "mail_provider": [],
      "hostname": "netdna-cdn.org",
      "host_provider": [],
      "alexa_rank": null
    }
  ],
  "record_count": 96
}