JustEmails · Schema

SendTransactionalRequest

EmailHostingCustomDomainMCP

Properties

Name	Type	Description
from	string	Sender address on a verified domain.
to	object
cc	object
bcc	object
subject	string
html	string
text	string
replyTo	string
idempotencyKey	string
trackOpens	boolean	Open tracking for this send (1x1 image in the HTML part). Omit for the account default, which is off. Approximate: Apple Mail Privacy Protection and image proxies load images without a reader.
trackClicks	boolean	Click tracking for this send (HTML links rewritten to a signed justemails.app redirect; plain text untouched). Omit for the account default, which is off.
tags	array
headers	object	Custom headers, one line each. Not allowed: From, To, Cc, Bcc, Subject, Date, Message-ID, DKIM-Signature (use the from, to, cc, bcc and subject fields), nor "key" and "value" together.

View JSON Schema on GitHub

JSON Schema

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://artifacts.apis.io/justemails-app/json-schema/justemails-app-send-transactional-request-schema.json",
  "title": "SendTransactionalRequest",
  "x-generated": "2026-11-13",
  "x-method": "derived",
  "x-generator": "derive-json-schema.py",
  "x-source": "openapi/justemails-app-openapi.json#/components/schemas/SendTransactionalRequest",
  "type": "object",
  "required": [
    "from",
    "to",
    "subject"
  ],
  "properties": {
    "from": {
      "type": "string",
      "format": "email",
      "description": "Sender address on a verified domain."
    },
    "to": {
      "oneOf": [
        {
          "type": "string",
          "format": "email"
        },
        {
          "type": "array",
          "items": {
            "type": "string",
            "format": "email"
          },
          "minItems": 1
        }
      ]
    },
    "cc": {
      "oneOf": [
        {
          "type": "string",
          "format": "email"
        },
        {
          "type": "array",
          "items": {
            "type": "string",
            "format": "email"
          }
        }
      ]
    },
    "bcc": {
      "oneOf": [
        {
          "type": "string",
          "format": "email"
        },
        {
          "type": "array",
          "items": {
            "type": "string",
            "format": "email"
          }
        }
      ]
    },
    "subject": {
      "type": "string",
      "maxLength": 998
    },
    "html": {
      "type": "string",
      "maxLength": 2000000
    },
    "text": {
      "type": "string",
      "maxLength": 2000000
    },
    "replyTo": {
      "type": "string",
      "format": "email"
    },
    "idempotencyKey": {
      "type": "string",
      "maxLength": 255
    },
    "trackOpens": {
      "type": "boolean",
      "description": "Open tracking for this send (1x1 image in the HTML part). Omit for the account default, which is off. Approximate: Apple Mail Privacy Protection and image proxies load images without a reader."
    },
    "trackClicks": {
      "type": "boolean",
      "description": "Click tracking for this send (HTML links rewritten to a signed justemails.app redirect; plain text untouched). Omit for the account default, which is off."
    },
    "tags": {
      "type": "array",
      "items": {
        "type": "string",
        "maxLength": 64
      },
      "maxItems": 10
    },
    "headers": {
      "type": "object",
      "additionalProperties": {
        "type": "string"
      },
      "description": "Custom headers, one line each. Not allowed: From, To, Cc, Bcc, Subject, Date, Message-ID, DKIM-Signature (use the from, to, cc, bcc and subject fields), nor \"key\" and \"value\" together."
    }
  }
}

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