Syntax and normalization
Reject malformed inputs and normalize the domain before downstream use.
Email Check API
Catch broken, disposable, role-based, and free-provider addresses before they pollute your workflow.
The promise
Fast contact hygiene without pretending we opened the mailbox.
Responses include a check timestamp and explicit boundaries, so your application can distinguish a negative result from an unavailable source or missing identity.
POST /v1/email/check
{ "email": "hello@example.com" }
{
"syntax_valid": true,
"mx_present": true,
"disposable": false,
"role_address": true,
"mailbox_status": "not_checked"
}What it checks
Useful signals with explicit boundaries.
Validate email syntax, MX records, disposable domains, role addresses and free providers with a REST API that never claims mailbox verification.
MX availability
Report whether the domain publishes mail exchange records at check time.
Address classification
Flag disposable domains, role addresses and common free-email providers.
Where it fits
Built for real workflow events.
LookTwice does not use SMTP probes, send messages or confirm that a mailbox exists. The response always reports mailbox_status as not_checked.
Signup form validation
Call /v1/email/check from this workflow and retain the returned evidence with the business event.
CRM import hygiene
Call /v1/email/check from this workflow and retain the returned evidence with the business event.
Lead routing and enrichment pipelines
Call /v1/email/check from this workflow and retain the returned evidence with the business event.
FAQ
Email Check questions.
Need the request schema or complete response fields? Continue to the API reference.
Does the API verify that an inbox exists?
No. It validates the address structure and domain-level signals without probing the mailbox or claiming deliverability.
Can I detect disposable email addresses?
Yes. The response includes a disposable classification based on the maintained domain dataset used for that request.
Does a valid result guarantee delivery?
No. A syntactically valid address with MX records can still reject mail. LookTwice states that boundary in every response.