Email verification: check if an address is real and safe to send

Email Validation checks a single email address and tells you whether it looks deliverable and how risky it is. Use it on signup forms, before a send or to clean a list you were handed.

What it tells you

• Whether the address is deliverable, based on its syntax and the mail servers behind the domain.
• The type of address it is, business for example, and what tier of provider is behind it.
• A quality score, whether the syntax is valid and the name pattern the address follows (for example, first name plus last name).
• Reputation signals for the domain, including honeypot risk (addresses planted to catch bulk senders).
• Deliverability factors such as whether mail servers are configured and whether the domain is catch-all (accepts mail for any address at it).
• A risk level, a fraud score and a suggested action so you can approve or hold the address.

What you need to provide

The email address you want to check. That is the only required input.

What it costs

1 credit per lookup. Live per-product costs are shown on the Billing page in your dashboard.

How to run it

• In the dashboard: Email Validation
• From your code: POST /v1/email, then see the Developer Hub at app.1lookup.io/developer-hub.

Good to know

• Results are point-in-time. A mailbox can be closed, or a domain can change its mail setup, after you run the check.
• The scores and the risk level are inputs to your decision, not a verdict. Set your own thresholds for what you accept, hold and reject.
• A catch-all domain accepts mail for any address at it, so the deliverability answer for those addresses carries less certainty than for a normal mailbox.
• Every response also carries the credits used and your remaining balance, so you can track spend as you go.
• An email address is personal data. Use it for legitimate business purposes only.

Updated on: 24/08/2026