API reference

Messages

Stored messages, with their deliveries and attachments.

Auth: Session token · Base URL: https://api.mailkite.dev

Endpoints

Each row expands to its request and response schema. The address bar follows along, so any endpoint can be linked to directly.

GET /api/messages List stored messages, newest first. Optionally filter with `search` (matches sender, recipient, or subject) and page with `before` (a `received_at` cursor) and `limit`; omit all for the default newest 100. Response is a bare array — paginate by passing the last row's `received_at` as the next `before`.

List stored messages, newest first. Optionally filter with `search` (matches sender, recipient, or subject) and page with `before` (a `received_at` cursor) and `limit`; omit all for the default newest 100. Response is a bare array — paginate by passing the last row's `received_at` as the next `before`.

Response body

array message.json

A stored message (msg_…), inbound or outbound. GET /api/messages returns list rows: the stored fields plus per-message delivery counters, without bodies. GET /api/messages/:id (see message-detail) returns the same resource with bodies (text_body/html_body/headers_json) and without the list counters.

Field	Type	Notes
id req	string	Message id (msg_…), stable across webhook retries and replays.
user_id req	string	Owning account (usr_…).
route_id	string · null	The route that handled an inbound message (rte_…); null for outbound sends.
mailbox_id	string · null	The mailbox the message is anchored to for access control; null when the address isn't on an owned domain.
direction req	"inbound" · "outbound"	Whether MailKite received or sent the message.
from req	object	Structured sender — the same shape the email.received webhook carries.
from.address req	string	Email address, from the SMTP envelope.
from.name	string	Display name decoded from the MIME header. Omitted when the message carried none or the header names a different address. Sender-asserted and unverified.
to req	object[]	Structured recipients — the same shape the email.received webhook carries.
to[].address req	string	Email address, from the SMTP envelope.
to[].name	string	Display name decoded from the MIME header. Omitted when the message carried none or the header names a different address. Sender-asserted and unverified.
from_addr req	string	Bare sender address from the SMTP envelope (MAIL FROM).
to_addr req	string	Bare recipient address from the SMTP envelope (RCPT TO).
subject	string · null	Decoded subject line; null when the message had none.
text_body	string · null	Plain-text body. Detail responses only — list rows never carry bodies.
html_body	string · null	HTML body. Detail responses only — list rows never carry bodies.
headers_json	string · null	Stored MIME headers as a JSON string. Detail responses only.
spf	string · null	SPF verdict for an inbound message ('pass', 'fail', …); null when not checked.
dkim	string · null	DKIM verdict for an inbound message; null when not checked.
dmarc	string · null	DMARC verdict for an inbound message; null when not checked.
spam	string · null	Spam verdict for an inbound message ('ham', 'spam'); null when not checked.
thread_id	string · null	Conversation root id — pass it to send()'s inReplyTo to reply in-thread. null when the message carried no usable id.
send_status	string	Outbound send state: 'sending', 'sent', or 'failed'. Always 'sent' for inbound rows.
track_id	string · null	Open-tracking token for an outbound message when tracking was on; null = off.
received_at req	integer	When MailKite accepted the message (arrival time — stable across retries and replays), in Unix epoch milliseconds (UTC).
size_bytes	integer · null	Stored byte size (headers + bodies; attachments sized separately).
delivery_count	integer	How many webhook deliveries exist for this message. List rows only.
attempts	integer · null	Max attempts across this message's deliveries. List rows only.
last_status_code	integer · null	HTTP status of the most recent delivery. List rows only.
delivered_count	integer	Deliveries in state 'delivered'. List rows only.
failed_count	integer	Deliveries in state 'failed'. List rows only.
pending_count	integer	Deliveries in state 'pending'. List rows only.
webhook_status	string · null	Rolled-up webhook state for the list pill ('delivered', 'failed', 'pending'); null when the message has no deliveries. List rows only.

An actual array of results, recorded from the conformance suite.

response.json

[
  {
    "id": "msg_2Hk9QpVn4tLd",
    "user_id": "usr_7Fj3MnQw",
    "route_id": "rte_4Bn8XcVm",
    "direction": "inbound",
    "from": {
      "address": "ada@example.com",
      "name": "Ada Lovelace"
    },
    "to": [
      {
        "address": "support@myapp.ai",
        "name": "Support"
      }
    ],
    "from_addr": "ada@example.com",
    "to_addr": "support@myapp.ai",
    "subject": "Invoice question",
    "thread_id": "msg_2Hk9QpVn4tLd",
    "received_at": 1769731200000,
    "size_bytes": 4821,
    "spf": "pass",
    "dkim": "pass",
    "dmarc": "pass",
    "spam": null,
    "send_status": "sent",
    "delivery_count": 1,
    "attempts": 1,
    "last_status_code": 200,
    "delivered_count": 1,
    "failed_count": 0,
    "pending_count": 0,
    "webhook_status": "delivered"
  }
]

message.json

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://api.mailkite.dev/v1/schemas/message.json",
  "title": "Message",
  "description": "A stored message (msg_…), inbound or outbound. GET /api/messages returns list rows: the stored fields plus per-message delivery counters, without bodies. GET /api/messages/:id (see message-detail) returns the same resource with bodies (text_body/html_body/headers_json) and without the list counters.",
  "type": "object",
  "required": [
    "id",
    "user_id",
    "direction",
    "from",
    "to",
    "from_addr",
    "to_addr",
    "received_at"
  ],
  "properties": {
    "id": {
      "type": "string",
      "description": "Message id (msg_…), stable across webhook retries and replays.",
      "examples": [
        "msg_2Hk9QpVn4tLd"
      ]
    },
    "user_id": {
      "type": "string",
      "description": "Owning account (usr_…).",
      "examples": [
        "usr_7Fj3MnQw"
      ]
    },
    "route_id": {
      "type": [
        "string",
        "null"
      ],
      "description": "The route that handled an inbound message (rte_…); null for outbound sends."
    },
    "mailbox_id": {
      "type": [
        "string",
        "null"
      ],
      "description": "The mailbox the message is anchored to for access control; null when the address isn't on an owned domain."
    },
    "direction": {
      "type": "string",
      "enum": [
        "inbound",
        "outbound"
      ],
      "description": "Whether MailKite received or sent the message."
    },
    "from": {
      "type": "object",
      "required": [
        "address"
      ],
      "description": "Structured sender — the same shape the email.received webhook carries.",
      "properties": {
        "address": {
          "type": "string",
          "description": "Email address, from the SMTP envelope.",
          "examples": [
            "ada@example.com"
          ]
        },
        "name": {
          "type": "string",
          "description": "Display name decoded from the MIME header. Omitted when the message carried none or the header names a different address. Sender-asserted and unverified.",
          "examples": [
            "Ada Lovelace"
          ]
        }
      }
    },
    "to": {
      "type": "array",
      "description": "Structured recipients — the same shape the email.received webhook carries.",
      "items": {
        "type": "object",
        "required": [
          "address"
        ],
        "description": "One recipient.",
        "properties": {
          "address": {
            "type": "string",
            "description": "Email address, from the SMTP envelope.",
            "examples": [
              "ada@example.com"
            ]
          },
          "name": {
            "type": "string",
            "description": "Display name decoded from the MIME header. Omitted when the message carried none or the header names a different address. Sender-asserted and unverified.",
            "examples": [
              "Ada Lovelace"
            ]
          }
        }
      }
    },
    "from_addr": {
      "type": "string",
      "description": "Bare sender address from the SMTP envelope (MAIL FROM).",
      "examples": [
        "ada@example.com"
      ]
    },
    "to_addr": {
      "type": "string",
      "description": "Bare recipient address from the SMTP envelope (RCPT TO).",
      "examples": [
        "support@myapp.ai"
      ]
    },
    "subject": {
      "type": [
        "string",
        "null"
      ],
      "description": "Decoded subject line; null when the message had none.",
      "examples": [
        "Invoice question"
      ]
    },
    "text_body": {
      "type": [
        "string",
        "null"
      ],
      "description": "Plain-text body. Detail responses only — list rows never carry bodies."
    },
    "html_body": {
      "type": [
        "string",
        "null"
      ],
      "description": "HTML body. Detail responses only — list rows never carry bodies."
    },
    "headers_json": {
      "type": [
        "string",
        "null"
      ],
      "description": "Stored MIME headers as a JSON string. Detail responses only."
    },
    "spf": {
      "type": [
        "string",
        "null"
      ],
      "description": "SPF verdict for an inbound message ('pass', 'fail', …); null when not checked.",
      "examples": [
        "pass"
      ]
    },
    "dkim": {
      "type": [
        "string",
        "null"
      ],
      "description": "DKIM verdict for an inbound message; null when not checked.",
      "examples": [
        "pass"
      ]
    },
    "dmarc": {
      "type": [
        "string",
        "null"
      ],
      "description": "DMARC verdict for an inbound message; null when not checked.",
      "examples": [
        "pass"
      ]
    },
    "spam": {
      "type": [
        "string",
        "null"
      ],
      "description": "Spam verdict for an inbound message ('ham', 'spam'); null when not checked."
    },
    "thread_id": {
      "type": [
        "string",
        "null"
      ],
      "description": "Conversation root id — pass it to send()'s inReplyTo to reply in-thread. null when the message carried no usable id.",
      "examples": [
        "msg_2Hk9QpVn4tLd"
      ]
    },
    "send_status": {
      "type": "string",
      "description": "Outbound send state: 'sending', 'sent', or 'failed'. Always 'sent' for inbound rows.",
      "examples": [
        "sent"
      ]
    },
    "track_id": {
      "type": [
        "string",
        "null"
      ],
      "description": "Open-tracking token for an outbound message when tracking was on; null = off."
    },
    "received_at": {
      "type": "integer",
      "description": "When MailKite accepted the message (arrival time — stable across retries and replays), in Unix epoch milliseconds (UTC).",
      "examples": [
        1769731200000
      ]
    },
    "size_bytes": {
      "type": [
        "integer",
        "null"
      ],
      "description": "Stored byte size (headers + bodies; attachments sized separately).",
      "examples": [
        4821
      ]
    },
    "delivery_count": {
      "type": "integer",
      "description": "How many webhook deliveries exist for this message. List rows only.",
      "examples": [
        1
      ]
    },
    "attempts": {
      "type": [
        "integer",
        "null"
      ],
      "description": "Max attempts across this message's deliveries. List rows only.",
      "examples": [
        1
      ]
    },
    "last_status_code": {
      "type": [
        "integer",
        "null"
      ],
      "description": "HTTP status of the most recent delivery. List rows only.",
      "examples": [
        200
      ]
    },
    "delivered_count": {
      "type": "integer",
      "description": "Deliveries in state 'delivered'. List rows only.",
      "examples": [
        1
      ]
    },
    "failed_count": {
      "type": "integer",
      "description": "Deliveries in state 'failed'. List rows only.",
      "examples": [
        0
      ]
    },
    "pending_count": {
      "type": "integer",
      "description": "Deliveries in state 'pending'. List rows only.",
      "examples": [
        0
      ]
    },
    "webhook_status": {
      "type": [
        "string",
        "null"
      ],
      "description": "Rolled-up webhook state for the list pill ('delivered', 'failed', 'pending'); null when the message has no deliveries. List rows only.",
      "examples": [
        "delivered"
      ]
    }
  }
}

GET /api/messages/:id Get a message with deliveries + attachments.

Get a message with deliveries + attachments.

Response body

message-detail.json

GET /api/messages/:id — the full message with its delivery history, pipeline events, per-attempt audit rows, recorded opens, and attachments.

Field	Type	Notes
message req	message	The message itself, with bodies (text_body/html_body/headers_json) and without the list-row counters.
message.id req	string	Message id (msg_…), stable across webhook retries and replays.
message.user_id req	string	Owning account (usr_…).
message.route_id	string · null	The route that handled an inbound message (rte_…); null for outbound sends.
message.mailbox_id	string · null	The mailbox the message is anchored to for access control; null when the address isn't on an owned domain.
message.direction req	"inbound" · "outbound"	Whether MailKite received or sent the message.
message.from req	object	Structured sender — the same shape the email.received webhook carries.
message.from.address req	string	Email address, from the SMTP envelope.
message.from.name	string	Display name decoded from the MIME header. Omitted when the message carried none or the header names a different address. Sender-asserted and unverified.
message.to req	object[]	Structured recipients — the same shape the email.received webhook carries.
message.to[].address req	string	Email address, from the SMTP envelope.
message.to[].name	string	Display name decoded from the MIME header. Omitted when the message carried none or the header names a different address. Sender-asserted and unverified.
message.from_addr req	string	Bare sender address from the SMTP envelope (MAIL FROM).
message.to_addr req	string	Bare recipient address from the SMTP envelope (RCPT TO).
message.subject	string · null	Decoded subject line; null when the message had none.
message.text_body	string · null	Plain-text body. Detail responses only — list rows never carry bodies.
message.html_body	string · null	HTML body. Detail responses only — list rows never carry bodies.
message.headers_json	string · null	Stored MIME headers as a JSON string. Detail responses only.
message.spf	string · null	SPF verdict for an inbound message ('pass', 'fail', …); null when not checked.
message.dkim	string · null	DKIM verdict for an inbound message; null when not checked.
message.dmarc	string · null	DMARC verdict for an inbound message; null when not checked.
message.spam	string · null	Spam verdict for an inbound message ('ham', 'spam'); null when not checked.
message.thread_id	string · null	Conversation root id — pass it to send()'s inReplyTo to reply in-thread. null when the message carried no usable id.
message.send_status	string	Outbound send state: 'sending', 'sent', or 'failed'. Always 'sent' for inbound rows.
message.track_id	string · null	Open-tracking token for an outbound message when tracking was on; null = off.
message.received_at req	integer	When MailKite accepted the message (arrival time — stable across retries and replays), in Unix epoch milliseconds (UTC).
message.size_bytes	integer · null	Stored byte size (headers + bodies; attachments sized separately).
message.delivery_count	integer	How many webhook deliveries exist for this message. List rows only.
message.attempts	integer · null	Max attempts across this message's deliveries. List rows only.
message.last_status_code	integer · null	HTTP status of the most recent delivery. List rows only.
message.delivered_count	integer	Deliveries in state 'delivered'. List rows only.
message.failed_count	integer	Deliveries in state 'failed'. List rows only.
message.pending_count	integer	Deliveries in state 'pending'. List rows only.
message.webhook_status	string · null	Rolled-up webhook state for the list pill ('delivered', 'failed', 'pending'); null when the message has no deliveries. List rows only.
actor_email req	string · null	When a team member sent this message as the domain owner: the acting member's email. null otherwise.
actor_team_name req	string · null	When a team member sent this message as the domain owner: the team's name. null otherwise.
deliveries req	delivery[]	Every webhook delivery of this message, newest last — retries and replays append.
deliveries[].id req	string	Delivery id (dlv_…).
deliveries[].message_id req	string	The message this delivery carries (msg_…).
deliveries[].route_id req	string	The route whose webhook was targeted (rte_…).
deliveries[].url req	string	The webhook URL the body was POSTed to.
deliveries[].status req	"pending" · "delivered" · "failed" · "paused"	Current state of this delivery.
deliveries[].attempts req	integer	How many attempts this delivery has made.
deliveries[].last_status_code	integer · null	HTTP status of the most recent attempt.
deliveries[].next_retry_at	integer · null	When the auto-retry cron will re-attempt a failed delivery; null when nothing is due, in Unix epoch milliseconds (UTC); null when it has never happened.
deliveries[].retry_attempts	integer	How many automatic retries have been scheduled so far.
deliveries[].created_at req	integer	When the delivery was created, in Unix epoch milliseconds (UTC).
deliveries[].updated_at req	integer	When the delivery last changed, in Unix epoch milliseconds (UTC).
events req	object[]	The pipeline timeline for this message (received → routed → webhook attempts → retries). Metadata only, never bodies.
events[].id req	string	Event id (evt_…).
events[].kind req	string	Event kind (e.g. 'email.received', 'webhook.delivered', 'webhook.failed', 'webhook.test').
events[].status req	"ok" · "fail" · "info"	Outcome facet.
events[].domain	string · null	Domain the event belongs to.
events[].route_id	string · null	Route involved, when any.
events[].message_id	string · null	Message involved, when any.
events[].delivery_id	string · null	Delivery involved, when any.
events[].target	string · null	Webhook URL / forward address / recipient, when relevant.
events[].code	integer · null	HTTP or provider status code, when relevant.
events[].message	string · null	Human-readable detail.
events[].created_at req	integer	When the event was recorded, in Unix epoch milliseconds (UTC).
deliveryAttempts req	object[]	Per-attempt audit rows (timing, response code/headers/body) behind the delivery inspector.
deliveryAttempts[].id req	string	Attempt id (att_…).
deliveryAttempts[].delivery_id req	string	The delivery this attempt belongs to (dlv_…).
deliveryAttempts[].message_id req	string	The message delivered (msg_…).
deliveryAttempts[].attempt_number req	integer	1-based attempt counter within the delivery.
deliveryAttempts[].ok req	0 · 1	1 when the attempt succeeded.
deliveryAttempts[].reason	string · null	Failure classification when not ok (e.g. 'http_5xx', 'timeout', 'no-ack').
deliveryAttempts[].response_status	integer · null	HTTP status the endpoint returned.
deliveryAttempts[].response_headers	string · null	Response headers as a JSON string.
deliveryAttempts[].response_body	string · null	Response body, truncated to ~4KB.
deliveryAttempts[].duration_ms	integer · null	Round-trip time of the attempt.
deliveryAttempts[].requested_at req	integer	When the attempt started, in Unix epoch milliseconds (UTC).
deliveryAttempts[].created_at req	integer	When the audit row was recorded, in Unix epoch milliseconds (UTC).
opens req	object[]	Recorded opens for an outbound message; empty when tracking was off or nothing was opened.
attachments req	object[]	Stored attachments with signed download URLs.
attachments[].id req	string	Attachment id.
attachments[].filename req	string	Original filename.
attachments[].contentType	string · null	MIME type.
attachments[].size req	integer	Size in bytes.
attachments[].contentId	string · null	MIME Content-ID for inline attachments.
attachments[].disposition	string · null	'inline' or 'attachment'.
attachments[].url req	string	Signed, time-limited download URL — valid 7 days, no credential needed.

An actual response, recorded from the conformance suite.

response.json

{
  "message": {
    "id": "msg_2Hk9QpVn4tLd",
    "user_id": "usr_7Fj3MnQw",
    "route_id": "rte_4Bn8XcVm",
    "direction": "inbound",
    "from": {
      "address": "ada@example.com",
      "name": "Ada Lovelace"
    },
    "to": [
      {
        "address": "support@myapp.ai",
        "name": "Support"
      }
    ],
    "from_addr": "ada@example.com",
    "to_addr": "support@myapp.ai",
    "subject": "Invoice question",
    "text_body": "Could you resend invoice 4021?",
    "html_body": null,
    "headers_json": null,
    "spf": "pass",
    "dkim": "pass",
    "dmarc": "pass",
    "spam": null,
    "thread_id": "msg_2Hk9QpVn4tLd",
    "send_status": "sent",
    "received_at": 1769731200000,
    "size_bytes": 4821
  },
  "actor_email": null,
  "actor_team_name": null,
  "deliveries": [
    {
      "id": "dlv_6Kp2LsWq",
      "message_id": "msg_2Hk9QpVn4tLd",
      "route_id": "rte_4Bn8XcVm",
      "url": "https://myapp.ai/hooks/mailkite",
      "status": "delivered",
      "attempts": 1,
      "last_status_code": 200,
      "created_at": 1769731200000,
      "updated_at": 1769731201000
    }
  ],
  "events": [
    {
      "id": "evt_8Rt5NmZx",
      "kind": "webhook.delivered",
      "status": "ok",
      "domain": "myapp.ai",
      "route_id": "rte_4Bn8XcVm",
      "message_id": "msg_2Hk9QpVn4tLd",
      "delivery_id": "dlv_6Kp2LsWq",
      "target": "https://myapp.ai/hooks/mailkite",
      "code": 200,
      "message": "delivered",
      "created_at": 1769731201000
    }
  ],
  "deliveryAttempts": [
    {
      "id": "att_3Yh7GbFd",
      "delivery_id": "dlv_6Kp2LsWq",
      "message_id": "msg_2Hk9QpVn4tLd",
      "attempt_number": 1,
      "ok": 1,
      "reason": null,
      "response_status": 200,
      "response_headers": null,
      "response_body": null,
      "duration_ms": 142,
      "requested_at": 1769731201000,
      "created_at": 1769731201000
    }
  ],
  "opens": [],
  "attachments": [
    {
      "id": "att0",
      "filename": "invoice-4021.pdf",
      "contentType": "application/pdf",
      "size": 20841,
      "contentId": null,
      "disposition": "attachment",
      "url": "https://api.mailkite.dev/att/msg_2Hk9QpVn4tLd/0?exp=1770336000&sig=9f2c"
    }
  ]
}

message-detail.json

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://api.mailkite.dev/v1/schemas/message-detail.json",
  "title": "Message detail",
  "description": "GET /api/messages/:id — the full message with its delivery history, pipeline events, per-attempt audit rows, recorded opens, and attachments.",
  "type": "object",
  "required": [
    "message",
    "actor_email",
    "actor_team_name",
    "deliveries",
    "events",
    "deliveryAttempts",
    "opens",
    "attachments"
  ],
  "properties": {
    "message": {
      "$ref": "message.json",
      "description": "The message itself, with bodies (text_body/html_body/headers_json) and without the list-row counters."
    },
    "actor_email": {
      "type": [
        "string",
        "null"
      ],
      "description": "When a team member sent this message as the domain owner: the acting member's email. null otherwise."
    },
    "actor_team_name": {
      "type": [
        "string",
        "null"
      ],
      "description": "When a team member sent this message as the domain owner: the team's name. null otherwise."
    },
    "deliveries": {
      "type": "array",
      "description": "Every webhook delivery of this message, newest last — retries and replays append.",
      "items": {
        "$ref": "delivery.json"
      }
    },
    "events": {
      "type": "array",
      "description": "The pipeline timeline for this message (received → routed → webhook attempts → retries). Metadata only, never bodies.",
      "items": {
        "type": "object",
        "required": [
          "id",
          "kind",
          "status",
          "created_at"
        ],
        "properties": {
          "id": {
            "type": "string",
            "description": "Event id (evt_…).",
            "examples": [
              "evt_8Rt5NmZx"
            ]
          },
          "kind": {
            "type": "string",
            "description": "Event kind (e.g. 'email.received', 'webhook.delivered', 'webhook.failed', 'webhook.test').",
            "examples": [
              "webhook.delivered"
            ]
          },
          "status": {
            "type": "string",
            "enum": [
              "ok",
              "fail",
              "info"
            ],
            "description": "Outcome facet."
          },
          "domain": {
            "type": [
              "string",
              "null"
            ],
            "description": "Domain the event belongs to."
          },
          "route_id": {
            "type": [
              "string",
              "null"
            ],
            "description": "Route involved, when any."
          },
          "message_id": {
            "type": [
              "string",
              "null"
            ],
            "description": "Message involved, when any."
          },
          "delivery_id": {
            "type": [
              "string",
              "null"
            ],
            "description": "Delivery involved, when any."
          },
          "target": {
            "type": [
              "string",
              "null"
            ],
            "description": "Webhook URL / forward address / recipient, when relevant."
          },
          "code": {
            "type": [
              "integer",
              "null"
            ],
            "description": "HTTP or provider status code, when relevant.",
            "examples": [
              200
            ]
          },
          "message": {
            "type": [
              "string",
              "null"
            ],
            "description": "Human-readable detail."
          },
          "created_at": {
            "type": "integer",
            "description": "When the event was recorded, in Unix epoch milliseconds (UTC).",
            "examples": [
              1769731200000
            ]
          }
        }
      }
    },
    "deliveryAttempts": {
      "type": "array",
      "description": "Per-attempt audit rows (timing, response code/headers/body) behind the delivery inspector.",
      "items": {
        "type": "object",
        "required": [
          "id",
          "delivery_id",
          "message_id",
          "attempt_number",
          "ok",
          "requested_at",
          "created_at"
        ],
        "properties": {
          "id": {
            "type": "string",
            "description": "Attempt id (att_…).",
            "examples": [
              "att_3Yh7GbFd"
            ]
          },
          "delivery_id": {
            "type": "string",
            "description": "The delivery this attempt belongs to (dlv_…).",
            "examples": [
              "dlv_6Kp2LsWq"
            ]
          },
          "message_id": {
            "type": "string",
            "description": "The message delivered (msg_…).",
            "examples": [
              "msg_2Hk9QpVn4tLd"
            ]
          },
          "attempt_number": {
            "type": "integer",
            "description": "1-based attempt counter within the delivery.",
            "examples": [
              1
            ]
          },
          "ok": {
            "type": "integer",
            "enum": [
              0,
              1
            ],
            "description": "1 when the attempt succeeded."
          },
          "reason": {
            "type": [
              "string",
              "null"
            ],
            "description": "Failure classification when not ok (e.g. 'http_5xx', 'timeout', 'no-ack')."
          },
          "response_status": {
            "type": [
              "integer",
              "null"
            ],
            "description": "HTTP status the endpoint returned.",
            "examples": [
              200
            ]
          },
          "response_headers": {
            "type": [
              "string",
              "null"
            ],
            "description": "Response headers as a JSON string."
          },
          "response_body": {
            "type": [
              "string",
              "null"
            ],
            "description": "Response body, truncated to ~4KB."
          },
          "duration_ms": {
            "type": [
              "integer",
              "null"
            ],
            "description": "Round-trip time of the attempt.",
            "examples": [
              142
            ]
          },
          "requested_at": {
            "type": "integer",
            "description": "When the attempt started, in Unix epoch milliseconds (UTC).",
            "examples": [
              1769731200000
            ]
          },
          "created_at": {
            "type": "integer",
            "description": "When the audit row was recorded, in Unix epoch milliseconds (UTC).",
            "examples": [
              1769731200000
            ]
          }
        }
      }
    },
    "opens": {
      "type": "array",
      "description": "Recorded opens for an outbound message; empty when tracking was off or nothing was opened.",
      "items": {
        "type": "object",
        "description": "One recorded open of an outbound message (present when open tracking was on). Machine opens (Apple MPP, Gmail proxy, scanners) are flagged so human counts stay meaningful."
      }
    },
    "attachments": {
      "type": "array",
      "description": "Stored attachments with signed download URLs.",
      "items": {
        "type": "object",
        "required": [
          "id",
          "filename",
          "size",
          "url"
        ],
        "properties": {
          "id": {
            "type": "string",
            "description": "Attachment id."
          },
          "filename": {
            "type": "string",
            "description": "Original filename.",
            "examples": [
              "invoice-4021.pdf"
            ]
          },
          "contentType": {
            "type": [
              "string",
              "null"
            ],
            "description": "MIME type.",
            "examples": [
              "application/pdf"
            ]
          },
          "size": {
            "type": "integer",
            "description": "Size in bytes.",
            "examples": [
              20841
            ]
          },
          "contentId": {
            "type": [
              "string",
              "null"
            ],
            "description": "MIME Content-ID for inline attachments."
          },
          "disposition": {
            "type": [
              "string",
              "null"
            ],
            "description": "'inline' or 'attachment'."
          },
          "url": {
            "type": "string",
            "description": "Signed, time-limited download URL — valid 7 days, no credential needed.",
            "examples": [
              "https://api.mailkite.dev/att/msg_2Hk9QpVn4tLd/0?exp=1770336000&sig=9f2c"
            ]
          }
        }
      }
    }
  }
}