Acceptable use policy

Last updated: 17 September 2026

This policy protects mailbox providers, the people behind the addresses our customers verify, and the reputation of our infrastructure. It applies to every customer and every API key.

1. What our service does, and does not do

• We check whether an email address is deliverable using DNS lookups and a short SMTP handshake of EHLO, MAIL FROM, RCPT TO and QUIT.
• We never transmit message content. No email is delivered to any address as part of verification.
• We apply per-destination connection and rate limits so that our checks stay well within the connection policies of receiving mail servers.
• We do not generate, guess or enumerate addresses. We only check addresses supplied by an authenticated customer.

2. Customer obligations

You may submit an address for verification only if you have a lawful basis to contact its owner, for example because they signed up to your service, are an existing customer, or gave consent. You may not submit:

• Purchased, rented, scraped, harvested or “found” lists.
• Addresses generated by permutation, dictionary or pattern guessing.
• Lists obtained from data breaches or other unlawful sources.
• Addresses for the purpose of locating, profiling or harassing an individual.

3. Prohibited activities

• Using results to send unsolicited bulk email, or any message that violates CAN-SPAM, GDPR, PECR, KVKK or similar law.
• Attempting to use the API or infrastructure to attack, overload or probe mail servers beyond normal verification.
• Reselling or redistributing results without a written reseller agreement.
• Circumventing rate limits, sharing API keys, or automated account creation.

4. Enforcement

We monitor usage patterns, bounce feedback and abuse reports. Accounts that breach this policy are suspended without refund, and we cooperate with mailbox providers, hosting providers and law-enforcement requests as required.

5. Reporting abuse

If you operate a mail server and believe our checks are causing problems, or if you believe a customer is misusing our service, email abuse@zyloriso.com or postmaster@zyloriso.com. Reports are acknowledged and acted on within 24 hours. Mail server operators may request that their domains be excluded from verification, and we honour such requests permanently.

6. Infrastructure identification

All verification connections originate from hostnames under v1.zyloriso.com, for example mx1.v1.zyloriso.com, with matching forward and reverse DNS, so that our traffic is always identifiable and accountable.