---
title: "Email Verification API with Honest Labels | Leadsets"
description: "Verify one email or a list of thousands. Verified, catch-all, unknown or invalid, with a confidence score and check time. Built into enrichment."
canonical: https://leadsets.ai/verify
updated: 2026-11-09
---

Email verification

# Know before you send.

Check one address or a list of thousands. Every result comes back with an honest label, a confidence score and the time it was checked, so your domain stays clean.

[Verify a list free](https://leadsets.ai/signup) [API reference](https://leadsets.ai/docs/quickstart)

The waterfall

## Cheap checks first. A second opinion only when it matters.

1. **Syntax and domain** Format, DNS and MX records, disposable and role addresses. Obvious failures stop here.
2. **Primary verifier** A mailbox-level check. Clear answers are stored with a timestamp.
3. **Second opinion** Uncertain, catch-all or conflicting results go to a second verifier.
4. **Honest label** Still unclear? It's labelled unknown. We never round it up to "valid."

### Built into enrichment

Every email from `enrich_person` is already verified. No second tool, no second bill.

### Bulk lists

Upload or POST a list, get an async job ID, and pull results when they're ready. On every paid plan.

### No mailbox probing tricks

An MX record isn't proof a mailbox exists. We don't pretend it is, and we don't hammer servers to find out.

## Let your agent do the list building.

1,000 free records. No card. First useful result in minutes.

[Get a free API key](https://leadsets.ai/signup)

## Questions and answers

### What is the difference between catch-all and unknown emails?

A catch-all domain accepts every address, so no one can confirm a specific mailbox: send at lower volume. Unknown means the mail server gave no clear answer: treat it as unconfirmed. Leadsets labels the two separately and never reports either as valid.

### How does email verification work?

Leadsets uses a waterfall: syntax, DNS and MX checks first (plus disposable and role addresses), then a mailbox-level check, then a second verifier for uncertain or catch-all results. Anything still unclear is labelled unknown.

### Is email verification included with enrichment?

Yes. Every email Leadsets returns from enrich_person is already verified, with no second tool and no second bill. Standalone verify_email counts toward the enrichment limit, and bulk lists run as async jobs on every paid plan.

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