atat.fastmail.us is a disposable email domain

atat.fastmail.us is a disposable temp email domain that provides throwaway email addresses and should be blocked. These temporary addresses are frequently exploited to bypass verification systems and create fake accounts.

Raw API JSON response:

{
    "valid": true,
    "block": true,
    "domain": "atat.fastmail.us",
    "base_domain": "fastmail.us",
    "text": "Disposable \/ temporary domain",
    "reason": "Disposable",
    "risk": 91,
    "is_disposable": true,
    "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": "103.168.172.217",
    "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": [
        "103.168.172.217",
        "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",
        "202.12.124.218",
        "202.12.124.219",
        "202.12.124.216",
        "202.12.124.217"
    ],
    "mx_priorities": {
        "us1-smtp.messagingengine.com": 10,
        "us2-smtp.messagingengine.com": 20
    },
    "email_provider": "Fastmail",
    "disposable_provider": null,
    "possible_typo": [],
    "domain_age_days": null,
    "domain_created_at": null,
    "block_status_changed_at": "2026-08-29T21:46:47+00:00"
}