Email Verification API

This API requires authentication. See Authentication Overview for details on using API key + secret or OAuth2 bearer tokens.

The Email Verification API takes an email address (potentially containing spelling mistakes and/or other errors) and validates the syntax, the existence and availability of the domain, the existence of the email account, and returns a verified state and other metadata.

Parameters

Endpoint

Global

https://api.addressfinder.io/api/email/v1/verification

Parameter	Description	Test Value
`key`	Your unique licence key (find on Portal credentials) Type: `string` `required`
`format`	The required format of the response. Default value: `json` Type: `string`
`email`	The email to be verified. Type: `string`
`domain`	Used to identify which of your services is calling the API for activity monitoring purposes. This domain needs to be registered in the portal. Type: `string`
`features`	A comma-separated list of parameters that controls the methods of verification to be completed. This will impact the query processing time and data returned in the response. Options: `domain` checks if the domain is configured to receive emails; `connection` checks if the email account exists; `provider` checks and returns the email service provider; `format` validates the syntax of the email address only. When `format` is the only feature, no domain, connection or provider checks are performed, so the response is returned faster and `is_verified` reflects the format check alone. The `is_disposable`, `is_role`, `is_public` and `is_catch_all` attributes are returned as `null` because they are not evaluated. Combining `format` with any other feature runs a standard verification. Default value: `domain,connection` Type: `string`

Responses

200 OK

Name	Description	Example
`email_account`	The first part of an email address, before the `@` Type: `string`	john.doe
`email_domain`	The second part of the email address, after the `@` Type: `string`	addressfinder.com
`email_provider_domain`	The underlying provider of the email service. Only populated if the features=provider parameter is provided. Type: `string`	google.com
`verified_email`	The full verified email address Type: `string`	jane.smith@addressfinder.com
`is_verified`	We did not find any reason to believe an email sent to the address provided would fail to reach the associated mailbox Type: `boolean`	true
`is_disposable`	Identified as a disposable email address. Returned as `null` for format-only checks (`features=format`), which do not evaluate this attribute. Type: `boolean`	false
`is_role`	The email account is for a group email. For example info@addressfinder.com. Returned as `null` for format-only checks (`features=format`), which do not evaluate this attribute. Type: `boolean`	false
`is_public`	Identified as a public email provider. For example john.doe@gmail.com. Returned as `null` for format-only checks (`features=format`), which do not evaluate this attribute. Type: `boolean`	false
`is_catch_all`	`true` if the email domain has a catch all policy and will accept mail sent to any address at that domain, `false` if the domain only accepts mail addressed to a specific mailbox. Returned as `null` when the status could not be determined, for example if the upstream mail server refused the connection or rate limited the check, and for format-only checks (`features=format`), which do not evaluate this attribute. Type: `boolean`	false
`not_verified_reason`	A short human-readable description of why the email did not verify, corresponding to `not_verified_code`. `null` when the email verified. Type: `string`	-
`not_verified_code`	A machine-readable code identifying why the email did not verify. `null` when the email verified. One of: `FORMAT_INVALID`: the email address syntax is invalid. `DNS_RECORD_MISSING`: the domain has no MX record, so it cannot receive email. `SMTP_INVALID`: the domain has no properly configured SMTP server. `EMAIL_ACCOUNT_MISSING`: the mailbox does not exist at the domain. `MAILBOX_FULL`: the mailbox exists but is full. Type: `string`	-
`deliverability`	A graded confidence level for whether mail sent to this address will arrive, where `is_verified` is a single boolean. One of: `DELIVERABLE`: the mailbox exists and can receive mail. `LIKELY_DELIVERABLE`: probably deliverable, for example the domain accepts all addresses (catch-all) so the individual mailbox cannot be confirmed. `UNLIKELY_DELIVERABLE`: probably not deliverable, for example the mailbox is full. `UNDELIVERABLE`: the address cannot receive mail, because of an invalid format, a domain that cannot receive email, or a mailbox that does not exist. `UNDETERMINED`: we could not reach a conclusion, for example the mail provider temporarily blocked or rate-limited our check. Safe to retry later, and does not consume a verification lookup. Also returned as `UNDETERMINED` for format-only checks (`features=format`), which do not evaluate this attribute. Type: `string`	DELIVERABLE
`success`	Indicates if the request was successful or not Type: `boolean`	true

400 Bad request

Name	Description	Example
`completions`	An empty array will be returned due to the error Type: `array`	-
`error_code`	A unique numerical value identifying the error that occured Type: `string`	1004
`message`	An informative message describing the error that occured Type: `string`	Secret not provided
`success`	Indicates if the request was successful or not Type: `boolean`	false

See API Error Reference for details.

401 Unauthorized

Name	Description	Example
`error_code`	A unique numerical value identifying the error that occurred Type: `string`	1030
`message`	An informative message describing the error that occurred. For error code 1030 this includes the token expiry time in UTC, for example "Token expired at 2026-08-24T05:15:57Z". Type: `string`	Token expired at 2026-08-24T05:15:57Z
`success`	Indicates that the request was not successful Type: `boolean`	false

See API Error Reference for details.