---
title: "Send a message to a session"
method: POST
path: "/v1/sessions/{session_id}/message"
---

# Send a message to a session

`POST /v1/sessions/{session_id}/message`

Send a message to an active Devin session. The session must be in a running state to receive messages. Returns null on success, or a detail message if the session is already suspended.

## Path parameters

- `session_id` string, required

## Request body

- PostMessageParams
  - `message` string, required

## Response `200`

Successful Response

- MessageSentResponse — Response when a message is sent to a session that is already in a specific state.
  - `detail` string, required

## Other responses

- `422` — Validation Error

---

[API](https://skmtc.net/devinenterprise/apis/devin-api-v1.md) · [All operations](https://skmtc.net/devinenterprise/apis/devin-api-v1/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/devinenterprise/devin-api-v1/versions/e3244476af1c/schema)