Is fastmail.us valid?

fastmail.us is a valid domain that should be allowed to do sign-ups and registrations. Based on our analysis, you should allow this domain.

Raw API JSON response:

{
    "valid": true,
    "block": false,
    "domain": "fastmail.us",
    "base_domain": "fastmail.us",
    "text": "Looks okay",
    "reason": "none",
    "risk": 20,
    "is_disposable": false,
    "is_email_forwarder": false,
    "is_public_free": false,
    "is_public_premium": true,
    "is_business_provider": false,
    "is_isp_email": false,
    "is_email_api": false,
    "is_web_hosting_email": false,
    "is_self_hosted": false,
    "is_parked": false,
    "is_role_based_email": false,
    "mx_host": "us1-smtp.messagingengine.com",
    "mx_ip": "103.168.172.218",
    "mx_info": "Using MX pointer us1-smtp.messagingengine.com from DNS with priority: 10",
    "mx_fallback": false,
    "mx_hosts": [
        "us1-smtp.messagingengine.com",
        "us2-smtp.messagingengine.com"
    ],
    "mx_ips": [
        "103.168.172.218",
        "103.168.172.219",
        "103.168.172.220",
        "103.168.172.221",
        "103.168.172.222",
        "103.168.172.223",
        "103.168.172.216",
        "103.168.172.217",
        "202.12.124.219",
        "202.12.124.216",
        "202.12.124.217",
        "202.12.124.218"
    ],
    "mx_priorities": {
        "us1-smtp.messagingengine.com": 10,
        "us2-smtp.messagingengine.com": 20
    },
    "email_provider": "Fastmail",
    "disposable_provider": null,
    "possible_typo": [],
    "domain_age_days": 8952,
    "domain_created_at": "2002-04-30T00:00:00+00:00",
    "block_status_changed_at": "2026-06-25T22:18:18+00:00"
}