Why am I limited to 1 verification per day from a VPN or datacenter IP?

If the Valid Email Checker free verifier tells you that you have already used your daily limit after a single check, you are almost certainly connecting from a VPN, a Tor exit, or a commercial datacenter IP. The free verifier runs an ASN risk check against every incoming request, and IPs in the higher-risk categories get a stricter quota: 1 verification per 24 hours instead of 3.

The asymmetry, explained

A normal user on a residential IP costs the platform maybe one verification a week — they hit the free tool when they need to check a suspicious address. A scraper running through a rotating VPN pool can attempt thousands a day, burning through provider quota and giving us nothing back. Treating both populations the same would mean either pricing the free tool out of existence or letting scrapers ruin it for everyone. Dropping the VPN/datacenter quota to 1 splits the difference: legitimate users on VPNs (privacy-conscious individuals, corporate VPN tunnels) still get one free check, while automated abuse pipelines find the tool too slow to be worth their time.

How the classification happens

Valid Email Checker maintains an internal asn_risk_list table that maps autonomous system numbers to risk categories. The table is seeded and refreshed by an abuse-sentinel coworker that pulls from public ASN catalogs and our own observed abuse signals. When the verifier receives a request, it does an inline lookup against your IP's ASN. If the ASN belongs to a commercial VPN, a known Tor exit, or a major cloud datacenter, the request is flagged and the lower quota applies.

Categories that trigger the lower limit

• Commercial VPN providers (NordVPN, ExpressVPN, ProtonVPN, Mullvad, Surfshark, and similar).
• Tor exit nodes — the IPs that route Tor traffic onto the open internet.
• Cloud datacenters (AWS, GCP, Azure, DigitalOcean, Vultr, Hetzner, OVH, Linode).
• Known hosting providers commonly used to run scrapers.

What if you actually need VPN access

Plenty of legitimate users are always on a VPN — corporate policy, privacy reasons, geographic restrictions. The free verifier is not the right tool for that population. Two cleaner paths:

• Sign up for free. The 200-credit signup grant gives you 200 verifications with no daily cap and no ASN-based throttle on the dashboard. Authenticated traffic is treated differently because the signup itself runs its own abuse scoring — see do I need an account to use the free tools.
• Switch off the VPN for the check. A residential IP gives you the full 3 per day immediately.