---
title: "Send a message to an existing session"
method: POST
path: "/v1/sessions/{session_id}/message"
tags: ["Sessions"]
---

# Send a message to an existing session

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

Interact with an active Devin session by sending a message. This is
particularly useful in sessions waiting for user input or confirmations.

## Path parameters

- `session_id` string, required

## Request body

- SendMessageRequest — Request body for sending a message to an existing Devin session
  - `message` string, required — The message to send to Devin

## Response `204`

No Content on success

## Other responses

- `400` — Bad Request
- `401` — Unauthorized - Invalid or missing API key
- `404` — Resource not found
- `500` — Internal Server Error

---

[API](https://skmtc.dev/devin/apis/devin-external-api.md) · [All operations](https://skmtc.dev/devin/apis/devin-external-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/devin/devin-external-api/revisions/bb0fabac5cbe/schema)