API reference / Messages

Reply to a message

Reply to an email only when authorized. Preserve idempotencyKey and contents on retries.

POST/v1/inboxes/{inboxId}/messages/{messageId}/reply

Requires an API key with the messages:send scope. MCP tool: reply. CLI: goshenemail messages reply.

Request

Path parameters

Name	Type	Required	Notes
`inboxId`	`string (email)`	Yes	up to 254 characters
`messageId`	`string`	Yes	1–998 characters

Body

Field	Type	Required	Notes
`attachments`	`object[]`		up to 10 items
`filename`	`string`	Yes	1–200 characters
`contentType`	`string`	Yes	up to 100 characters
`content`	`string`	Yes	up to 2,796,204 characters
`labels`	`string[]`		up to 50 items
`text`	`string`		up to 2,000,000 characters
`html`	`string`		up to 2,000,000 characters
`replyAll`	`boolean`		default false
`to`	`string (email)[]`		at least 1 item, up to 50 items
`cc`	`string (email)[]`		up to 50 items
`bcc`	`string (email)[]`		up to 50 items
`idempotencyKey`	`string`	Yes	1–200 characters

Response

Field	Type	Notes
`messageId`	`string`
`threadId`	`string`
`deduplicated`	`boolean`

Errors return { "error": { "code", "message", "transient" } } with a 4xx or 5xx status. See Errors.

Examples

curl

curl "https://api.goshenemail.com/v1/inboxes/research%40agents.goshenemail.com/messages/%3C20260920.12345%40agents.goshenemail.com%3E/reply" \
  -H "Authorization: Bearer $GOSHENEMAIL_API_KEY" \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "text": "Hello, could you send the current quote?",
    "idempotencyKey": "2f7c1c1e-6d1a-4a3b-9b0e-0c9b3f5c8a11"
  }'

CLI

goshenemail messages reply --inbox-id "research@agents.goshenemail.com" --message-id "<20260920.12345@agents.goshenemail.com>" --text "Hello, could you send the current quote?" --idempotency-key "2f7c1c1e-6d1a-4a3b-9b0e-0c9b3f5c8a11"