---
title: "Send Message"
method: POST
path: "/v1/messages"
tags: ["Messages"]
---

# Send Message

`POST /v1/messages`

## Request

- Base URL: `https://api.agentline.cloud`
- URL: `https://api.agentline.cloud/v1/messages`
- Auth: HTTP bearer

Send an outbound SMS message from an AI agent's phone number.

## Request body

- MessageSend
  - `agent_id` string, required: ID of the AI agent sending the SMS (e.g. 'agt_abc123')
  - `to_number` string, required: Destination phone number in E.164 format (e.g. '+12125551234')
  - `body` string, required: SMS message text content
  - `media_url` string, nullable: URL of media to attach (MMS)
  - `from_number_id` string, nullable: Specific phone number ID to send from; defaults to the agent's assigned number

## Response `200`

Successful Response

- unknown

## Other responses

- `422`: Validation Error

---

[API](https://skmtc.dev/agentline/apis/agentline-prepaid-phone-service-for-ai-agents.md) · [All operations](https://skmtc.dev/agentline/apis/agentline-prepaid-phone-service-for-ai-agents/llms.txt) · [OpenAPI document](https://skmtc.dev/agentline/apis/agentline-prepaid-phone-service-for-ai-agents/revisions/18c0bdbb4b30?raw)