KaiCalls Email API

openapi: 3.2.0
info:
  title: KaiCalls Public Email API
  version: '2026-06-05'
  description: Machine-readable surface for KaiCalls external developers and client agents.
servers:
- url: https://www.kaicalls.com/api
security:
- bearerAuth: []
tags:
- name: Email
paths:
  /v1/email/send:
    post:
      summary: Send a single transactional email from a workspace's verified domain…
      description: Sends a one-off transactional or 1:1 email (such as booking confirmations, reschedules, cancellations, or customer updates) from the business's own verified sending domain. Enforces per-business domain ownership, recipient bounce/complaint suppression, lead do-not-contact rules, and idempotency replay protection.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
              - business_id
              - to
              - subject
              properties:
                business_id:
                  type: string
                  format: uuid
                to:
                  type: string
                  format: email
                from:
                  type: string
                  description: Optional verified sender address on the business domain; defaults to the primary verified sender.
                from_name:
                  type: string
                reply_to:
                  type: string
                  format: email
                subject:
                  type: string
                  minLength: 1
                  maxLength: 200
                html:
                  type: string
                text:
                  type: string
                purpose:
                  type: string
                  enum:
                  - booking_confirmation
                  - booking_rescheduled
                  - booking_cancelled
                  - booking_alert
                  - lead_reply
                  - notification
                  - transactional
                lead_id:
                  type: string
                  format: uuid
                idempotency_key:
                  type: string
                metadata:
                  type: object
                  additionalProperties: true
      responses:
        '200':
          description: Transactional email accepted by provider.
        '400':
          description: Invalid request or suppressed recipient (email_suppressed).
        '403':
          description: Missing emails:write scope, no access to business_id, or unverified_sender_domain.
        '404':
          description: Lead not found for this business.
        '409':
          description: sender_not_verified or idempotency_conflict.
        '502':
          description: Provider send failed (email_send_failed).
      x-required-scopes: emails:write
      tags:
      - Email
      operationId: postV1EmailSend
      x-operation-id-source: derived
components:
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: 'KaiCalls API key. Per-operation scope requirements are published on each operation as `x-required-scopes` — a scope string, or a nested `{ allOf: [...] }` / `{ anyOf: [...] }` expression. An operation with no `x-required-scopes` requires a valid key but no particular scope.'
      x-scopes:
      - workspaces:read
      - workspaces:write
      - numbers:read
      - numbers:write
      - agents:read
      - agents:write
      - communication-runs:read
      - communication-runs:write
      - calls:read
      - calls:write
      - sms:read
      - sms:write
      - webhooks:read
      - webhooks:write
      - events:read
      - events:replay
      - lifecycle:write
      - leads:read
      - leads:write
      - emails:read
      - emails:write
      - sdr:read
      - sdr:write
      - evals:read
      - evals:write
      - appointments:read
      - appointments:write
      - knowledge:read
      - knowledge:write
      - products:read
      - products:write
      - integrations:write
      - approvals:write
      - concierge:write
      - billing:read
      - billing:write
      - call_evidence:read
      - call_evidence:write
      - support:write
    sessionAuth:
      type: apiKey
      in: cookie
      name: sb-access-token
      description: Authenticated dashboard session cookie. Used by first-party flows that mint or manage API keys.