Email Validation Skill

Overview

An email verification API and email checker for signup forms and CRM imports. Email Validator checks the address format, resolves the domain's MX records, follows the RFC fallback to the domain's A record, flags domains that publish a null MX, and reports whether the domain has SPF and DMARC records. It matches the domain against free, disposable and role-account lists, and returns a normalized address so +tag and Gmail-dot variants collapse to one. Every check runs over DNS, with no SMTP mailbox probe, so a slow mail server never holds up the response. Paid plans add a risk score and a suggested correction for domain typos.

Live Test Email Validation Skill Skill →

The tool

Once your client is connected to the VerveKit server, this appears in its tool list as EmailValidationSkill. It is read-only and open-world — it fetches and never mutates anything on your side — so most clients call it without asking you to confirm.

Tool call

{
  "name": "EmailValidationSkill",
  "arguments": {
    "email": "[email protected]"
  }
}

You do not name the tool yourself; the model picks it. Asking about [email protected] in the terms this skill covers is enough for it to reach for EmailValidationSkill on its own — naming it explicitly also works, and is the way to force the call.

Connecting

One server URL covers every skill in the catalog, including this one. Authorization is OAuth: the client opens a browser once, and there is no key to paste into a config file.

{
  "mcpServers": {
    "vervekit": {
      "url": "https://api.vervekit.com/v1/mcp"
    }
  }
}

Per-client setup — Claude, Cursor, VS Code, ChatGPT — is on the MCP setup page.

Arguments

These are the properties on the tool's inputSchema, so a well-behaved client validates them before the call is made. Premium arguments are accepted on every plan but only take effect on plans that include them.

Argument	Type	Description
`email`Required	string	The email address to validate (e.g., [email protected]) email

What the model gets back

The result carries a structuredContent object matching the tool's declared outputSchema, so a client reads fields without parsing prose. status is "ok" and error is null on success; a null field means the value was not available for that input, not that the call failed.

Result

{
  "status": "ok",
  "error": null,
  "data": {
    "email": "[email protected]",
    "domain": "myspace.com",
    "username": "support",
    "isRegexValid": true,
    "hasTypo": false,
    "isMxValid": true,
    "isValid": true,
    "isFreeEmail": false,
    "isCompanyEmail": true,
    "isDisposable": false,
    "isRoleAccount": true,
    "mxRecord": "mxa-00ac0e01.gslb.pphosted.com",
    "isNullMx": false,
    "canReceiveMail": true,
    "hasSpf": true,
    "hasDmarc": true,
    "isSubaddressed": false,
    "normalizedEmail": "[email protected]",
    "suggestedCorrection": null,
    "mailProvider": "Proofpoint",
    "isSecurityGateway": true,
    "roleCategory": "support",
    "riskScore": 10,
    "riskLevel": "low"
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Field	Type	Example	Description
`email`	string	`[email protected]`	The email address that was validated
`domain`	string	`myspace.com`	The domain portion extracted from the email
`username`	string	`support`	The username (local part) extracted from the email
`isRegexValid`	boolean	`true`	Email passes standard regex format validation
`hasTypo`	boolean	`false`	The address is malformed and fails format validation
`isMxValid`	boolean	`true`	The domain has valid mail exchange (MX) records and can receive mail
`isValid`	boolean	`true`	Indicates whether the email address is valid
`isFreeEmail`	boolean	`false`	Domain belongs to a free consumer email provider
`isCompanyEmail`	boolean	`true`	Domain appears to be a corporate/company domain
`isDisposable`	boolean	`false`	Domain is a known disposable or throwaway email provider
`isRoleAccount`	boolean	`true`	Mailbox is a role or shared address (e.g. info@, support@, noreply@) rather than a person
`mxRecord`	string	`mxa-00ac0e01.gslb.pphosted.com`	The preferred (lowest-priority) mail exchanger host for the domain, or null when it has none
`isNullMx`	boolean	`false`	The domain publishes a null MX record (RFC 7505), declaring that it accepts no email
`canReceiveMail`	boolean	`true`	The domain can be sent mail: it has a real MX record, or no MX at all but an A record that mail falls back to (RFC 5321). Null if the fallback lookup could not complete. Unlike isMxValid, this follows the RFC fallback, so a parked domain with only a website address can be true
`hasSpf`	boolean	`true`	The domain publishes an SPF (v=spf1) record, a sign it is set up to send mail. Null if the TXT lookup could not complete
`hasDmarc`	boolean	`true`	The domain publishes a DMARC (v=DMARC1) record at _dmarc. Null if the lookup could not complete
`isSubaddressed`	boolean	`false`	The address uses a +tag sub-address, e.g. [email protected]
`normalizedEmail`	string	`[email protected]`	Canonical address for spotting duplicates: the +tag removed, and for Gmail the dots too (googlemail.com folds into gmail.com). Not a deliverability claim
`suggestedCorrection`Premium	object	`null`	The likely intended email when a common domain typo is detected (e.g. gmial.com to gmail.com), otherwise null
`mailProvider`Premium	string	`Proofpoint`	Who handles the domain's incoming mail, read from its MX records: Google, Microsoft, Zoho, Proofpoint and about 25 others. Null when the domain runs its own mail servers or uses a provider not on the list
`isSecurityGateway`Premium	boolean	`true`	True when mailProvider is an email security gateway (Proofpoint, Mimecast, Cisco and similar) that filters mail before it reaches the real mailbox host, which is typical of larger companies; null when mailProvider is null
`roleCategory`Premium	string	`support`	What a role mailbox is for: general, support, sales, marketing, press, billing, hr, legal, security, technical or noreply. Null for a personal address Set only when isRoleAccount is true. Use it to route or filter by purpose, for example accept billing@ on an invoicing form but reject noreply@ on a signup form.
`riskScore`Premium	number	`10`	Composite 0-100 risk score combining deliverability, disposable, role and format signals (higher is riskier)
`riskLevel`Premium	string	`low`	Risk band derived from the score: low, medium or high

Failure modes

Errors come back as tool errors carrying a sentence the model can act on, not a bare status code. Error handling covers the full list.

Status	What it means
`400` / `422`	The arguments did not validate. The message names the offending one.
`401`	The OAuth session is invalid or expired — reconnect the server.
`403`	Blocked by a key restriction or an IP allow-list. Never a bad identity.
`404`	This skill is not part of VerveKit. Check the catalog.
`429`	Out of credits, or a brief rate limit. The message tells them apart.

A call costs 20 credits each time the tool actually runs; a model that reasons about the tool without calling it costs nothing.

Use cases

Signup Abuse Prevention: To stop fake signups, SaaS onboarding flows block temporary addresses by checking disposable flags before creating new trial accounts.
B2B Lead Routing: Sales teams verify company domains against free provider flags to route corporate inquiries directly to account executives.
Mailing List Hygiene: When scrubbing subscriber databases, email marketers filter out missing mail records and invalid syntax to protect sender reputation.
Customer Support Routing: Flag shared inboxes like billing or support addresses during ticket submission to direct automated receipts to named team members instead.
Free Trial Abuse: Store the normalized address at signup so [email protected] and [email protected] count as one person when a product hands out free trials or credits.

Other ways to use Email Validation Skill

Set up Email Validation Skill on VerveKit, or reach the same source a different way. Your VerveKit account and credits work on all of them — one key, one balance.

Call it as a REST APIOne HTTPS endpoint and an x-api-key header, with SDKs for Node, Python and .NET.APIVerve →Reference →

Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.VerveSheets →Reference →

Ground an agent on itA cited, machine-checkable fact your model can't produce on its own.VerveContext →Reference →

Pages that use this skill:

Block fake signupsGuides
CodaIntegrations
Node-REDIntegrations
Response formatReference