How does SMTP email validation work?

The API connects to the recipient's mail server, simulates the start of an email delivery (RCPT TO command), and checks whether the mailbox exists - all without sending a message. This happens in milliseconds and confirms the email is real.

What is a catch-all domain?

A catch-all domain is configured to accept emails sent to any address at that domain, even non-existent ones. The API detects these and flags them as 'risky' since you can't confirm the specific mailbox exists.

Can I validate emails in bulk?

Yes. The batch endpoint accepts up to 500,000 emails per request. You submit the batch, poll for progress, and retrieve paginated results. Webhook callbacks notify you per-result or on batch completion.

What verdicts does the API return?

The API returns three verdicts: valid (deliverable), risky (catch-all or unable to verify), and invalid (mailbox not found, domain expired, syntax error). Each verdict includes specific reason codes for programmatic handling.

Validate · API

Verify email addresses before you send

The Email Validation API confirms that email addresses are valid and can receive messages. It performs real-time SMTP verification, detects catch-all domains, identifies disposable email providers, and checks for syntax and DNS issues. Results include a clear valid/risky/invalid verdict with detailed reason codes.

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Features

SMTP Verification

Connects to the recipient's mail server and verifies the mailbox exists without sending a message.

Catch-All Detection

Identifies domains configured to accept all emails regardless of the mailbox, flagging them as risky.

Disposable Email Detection

Detects temporary and disposable email providers (Guerrilla Mail, Mailinator, etc.) used to avoid spam.

Bulk Validation

Validate up to 500,000 email addresses in a single batch request with webhook notifications.

Detailed Verdicts

Returns valid/risky/invalid status with specific reason codes (mailbox not found, domain expired, etc.).

Free Online Tool

Validate individual emails for free at enrich.so/free-tools/email-validation with no signup required.

API Endpoints

POST/email-validationValidate a single email address in real-time

POST/email-validation/batchSubmit up to 500,000 emails for batch validation

GET/email-validation/batch/{batchId}Check batch validation job progress

GET/email-validation/batch/{batchId}/resultsRetrieve paginated batch validation results

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Use Cases

Pre-send verification - validate email lists before outreach to prevent bounces
Form validation - verify emails at point of capture on signup and contact forms
CRM hygiene - periodically validate existing contacts to remove invalid addresses
List cleaning - scrub purchased or imported lists before loading into email tools
Bounce prevention - maintain sender reputation by keeping bounce rates below 2%
Fraud prevention - detect disposable emails during account registration

Pricing

Pay-as-you-go starting at $0.019 per validation. Volume discounts available down to $0.01 per validation at 500K+ scale. Free online tool available for individual validations.

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Frequently Asked Questions

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