API Evangelist enhancements for Email Verifier API Verification API

overlay: 1.0.0
info:
  title: API Evangelist enhancements for Email Verifier API Verification API
  version: 1.0.0
x-generated: '2026-08-13'
x-method: generated
x-source: openapi/email-verifier-api-verification-api-openapi.yml
extends: openapi/email-verifier-api-verification-api-openapi.yml
x-note: |-
  Captures the API Evangelist enrichment as an OpenAPI Overlay 1.0.0 document rather than
  mutating the harvested specification. Applying this overlay attaches the provenance,
  metering, agent-hazard and convention findings from this repo to the spec itself, so a
  consumer who resolves only the OpenAPI still sees them.
actions:
  - target: $.info
    update:
      x-apievangelist-profile: https://apis.io/provider/email-verifier-api/
      x-apievangelist-enriched: '2026-08-13'
      x-artifact-conventions: conventions/email-verifier-api-conventions.yml
      x-artifact-errors: errors/email-verifier-api-problem-types.yml
      x-artifact-data-model: data-model/email-verifier-api-data-model.yml
      x-artifact-plans: plans/email-verifier-api-plans-pricing.yml
      x-artifact-rate-limits: rate-limits/email-verifier-api-rate-limits.yml
      x-artifact-lifecycle: lifecycle/email-verifier-api-lifecycle.yml
      x-artifact-conformance: conformance/email-verifier-api-conformance.yml
  - target: $.info
    update:
      x-lifecycle:
        versioning: uri-path
        current: v2
        status_page: null
        changelog: null
        deprecation_policy: null
      x-agent-hazards:
        - >-
          A 200 OK does not mean the address is deliverable. Branch on `status`
          (passed|failed|unknown|transient) and then on `event`, never on the HTTP status alone.
        - >-
          The API key is a QUERY parameter and is written to any intermediary access log.
          Prefer the POST form and rotate keys that may have been logged.
        - >-
          Format is selected with `?xml=true`, not with an `Accept` header. Content negotiation
          is ignored.
        - >-
          There is no idempotency key and no de-duplication. A blind retry of a Paid event is
          billed a second time; cache results client-side keyed on the normalized address.
  - target: $.paths['/'].get
    update:
      x-metering:
        model: credit
        paid_events: [mailboxExists, mailboxDoesNotExist, mailboxIsFull]
        free_events: [invalidSyntax, domainDoesNotExist, mxServerDoesNotExist, isCatchall, isGreylisting, transientError]
        balance_field: remaining
      x-idempotent: true
      x-idempotency-key: null
      x-safe: true
  - target: $.paths['/'].post
    update:
      x-metering:
        model: credit
        paid_events: [mailboxExists, mailboxDoesNotExist, mailboxIsFull]
        free_events: [invalidSyntax, domainDoesNotExist, mxServerDoesNotExist, isCatchall, isGreylisting, transientError]
        balance_field: remaining
      x-idempotent: true
      x-idempotency-key: null
      x-recommended-for: server-to-server and agent traffic — keeps the address out of URLs and access logs
  - target: $.components.securitySchemes.apiKeyQuery
    update:
      x-transport-risk: >-
        Credential travels in the query string and is recorded by proxy, CDN and web-server
        access logs, browser history, and Referer headers. No header-based alternative is
        documented.
  - target: $.components.schemas.VerificationResult.properties.remaining
    update:
      x-note: >-
        Typed as a string although it carries an integer credit count. Parse defensively.
  - target: $.components.schemas.Error
    update:
      x-error-format: vendor-envelope
      x-not-rfc9457: true
      x-note: >-
        Shares the `status`, `event` and `details` field names with VerificationResult, so
        success and failure cannot be distinguished by document shape.