name: Email Verifier API Vocabulary
version: '1.0'
description: |-
  Domain vocabulary, taxonomy, and term definitions for the Email Verifier API. Captures
  the operational concepts of email-address verification: deliverability verdicts, event
  codes, intelligence flags, and the 16 verification points exercised by the engine.
namespace: https://emailverifierapi.com/vocab#
created: '2026-05-06'
modified: '2026-05-06'
tags:
  - Email Verification
  - Deliverability
  - SMTP Check
  - Bounce Prevention
terms:
  - name: VerificationResult
    definition: The structured outcome of a single email-address verification call.
  - name: Status
    definition: |-
      Top-level deliverability verdict for a verified address. One of `passed`,
      `failed`, `unknown`, or `transient`.
    values:
      - passed
      - failed
      - unknown
      - transient
  - name: Event
    definition: |-
      Fine-grained outcome code returned alongside the status, identifying which of the
      16 verification points produced the verdict.
    values:
      - mailboxExists
      - mailboxDoesNotExist
      - mailboxIsFull
      - domainDoesNotExist
      - mxServerDoesNotExist
      - invalidSyntax
      - isCatchall
      - isGreylisting
      - transientError
  - name: SyntaxCheck
    definition: RFC 5321/5322 lexical validation of the email address.
  - name: SmtpHandshake
    definition: Real-time SMTP RCPT TO probe to confirm the mailbox accepts mail.
  - name: MxRecord
    definition: DNS MX record lookup to resolve the mail exchange server for the domain.
  - name: DnsValidation
    definition: Verification that the domain has active DNS records.
  - name: SpamTrap
    definition: Honeypot or recycled address used by ISPs and blocklist operators to detect senders.
  - name: Complainer
    definition: User who frequently marks email as spam, depressing sender reputation.
  - name: Greylisting
    definition: Temporary SMTP defense in which the receiving server defers the first delivery attempt.
  - name: MailboxFull
    definition: Mailbox is over its storage quota and is rejecting new mail.
  - name: TypoSuggest
    definition: Domain misspelling correction (gmial.com -> gmail.com).
  - name: Disposable
    definition: Burner / temporary email provider where addresses self-destruct or rotate.
  - name: RoleAccount
    definition: Departmental alias such as info@, sales@, support@, marketing@.
  - name: CatchAll
    definition: Mail server that accepts all addresses for the domain regardless of mailbox existence.
  - name: GibberishDetection
    definition: Heuristic that flags machine-generated or keyboard-smash local parts.
  - name: OffensiveContent
    definition: Local part containing profanity or otherwise unsafe-for-brand language.
  - name: B2BLeadScoring
    definition: Classification of an address as corporate (B2B) versus consumer (B2C).
  - name: SmtpProvider
    definition: Identification of the underlying email host (Google, Microsoft 365, Yahoo, etc.).
  - name: Credit
    definition: Unit of metered consumption. Paid events consume one credit; free events do not.
  - name: PaidEvent
    definition: Event whose result depends on an SMTP probe and therefore consumes a credit.
  - name: FreeEvent
    definition: Event resolved deterministically (syntax / DNS / MX) and not charged against credits.
maintainers:
  - FN: Kin Lane
    email: kin@apievangelist.com