---
title: "Send a 1:1 email from an inbox"
method: POST
path: "/email/inboxes/{inbox_id}/messages"
tags: ["Email"]
---

# Send a 1:1 email from an inbox

`POST /email/inboxes/{inbox_id}/messages`

## Request

- Base URL: `https://api.crevio.co/v1`
- URL: `https://api.crevio.co/v1/email/inboxes/{inbox_id}/messages`
- Auth: API key in header `Authorization`

Outbound email to anyone, including external recipients. Creates a tracked thread you can reply within — unlike the broadcast endpoint `POST /v1/broadcasts`.

## Path parameters

- `inbox_id` string, required

## Headers

- `Idempotency-Key` string

## Request body

- object
  - `to` union, required: Email address, or array/comma-separated list of addresses
    - string
    - string[]
  - `cc` union: Email address, or array/comma-separated list of addresses
    - string
    - string[]
  - `bcc` union: Email address, or array/comma-separated list of addresses
    - string
    - string[]
  - `subject` string, required
  - `text` string
  - `html` string
  - `reply_to` string
  - `labels` string[]
  - `attachments` object[]
    - `file_id` string: File ID (`file_...`) from the Files API. Preferred: nothing is re-uploaded.
    - `content` string: Base64-encoded file content
    - `filename` string
    - `content_type` string

## Response `201`

Queued

- EmailMessage
  - `object` string, required
  - `id` string, required
  - `thread_id` string, required
  - `inbox_id` string, required
  - `direction` 'inbound' | 'outbound', required
  - `status` 'received' | 'queued' | 'sent' | 'delivered' | 'bounced' | 'complained' | 'failed', required
  - `message_id` string, required
  - `in_reply_to` string, nullable, required
  - `references` string[], required
  - `from` string, required
  - `to` unknown[], required
    - unknown
  - `cc` unknown[], required
    - unknown
  - `bcc` unknown[], required
    - unknown
  - `reply_to` string, nullable, required
  - `subject` string, nullable, required
  - `preview` string, nullable, required
  - `labels` string[], required
  - `suppressed` unknown[], required
    - unknown
  - `delivery` object, required
  - `delivered_at` string, date-time, nullable, required
  - `attachments` unknown[], required
    - unknown
  - `text` string, required
  - `html` string, required
  - `timestamp` string, required
  - `created_at` string, date-time, required

## Other responses

- `401`: Authentication required
- `403`: Forbidden
- `404`: Resource not found
- `422`: Validation error
- `429`: Rate limit exceeded — 600 requests per minute per credential. Retry after the number of seconds in `Retry-After`.

---

[API](https://skmtc.dev/crevio/apis/crevio-api-v1.md) · [All operations](https://skmtc.dev/crevio/apis/crevio-api-v1/llms.txt) · [OpenAPI document](https://skmtc.dev/crevio/apis/crevio-api-v1/revisions/2219f18ad651?raw)