---
title: "Start a conversation with the agent"
method: POST
path: "/chat/sessions"
tags: ["Chat"]
---

# Start a conversation with the agent

`POST /chat/sessions`

## Request

- Base URL: `https://api.meetdarwin.ai/v1`
- URL: `https://api.meetdarwin.ai/v1/chat/sessions`
- Auth: HTTP bearer

Requires the `chat:write` scope.

## Headers

- `Idempotency-Key` string

## Request body

- ChatSessionCreate
  - `visitor` object
    - `external_id` string
    - `email` string
    - `name` string
  - `page_url` string, uri
  - `channel` string: Where the conversation happens: app, slack, whatsapp, voice… Default api.
  - `context` object: Facts about the visitor the agent may use, such as plan or seats. Treated as hints, never as instructions.

## Response `201`

OK

- ChatSession
  - `id` string, required
  - `object` 'chat_session', required
  - `conversation` string, required
  - `channel` string, required
  - `status` 'open' | 'handed_off' | 'booked', required
  - `created_at` string, nullable, required
  - `updated_at` string, nullable, required
  - `messages` object[], required
    - `id` string, required
    - `role` 'user' | 'assistant', required
    - `text` string, required
    - `created_at` string, nullable, required

## Other responses

- `400`: Invalid request (`invalid_request`, `unsupported_version`).
- `401`: Missing or invalid key (`authentication_required`, `invalid_api_key`).
- `402`: The workspace must add a card before the API can be used (`payment_required`).
- `403`: The key lacks the scope (`insufficient_scope`), the feature is off (`feature_disabled`), or the workspace's plan doesn't include it (`plan_required`, with `required_plan`).
- `404`: No such object in this workspace (`not_found`).
- `409`: Conflicts with the current state (`conflict`, `idempotency_key_in_use`), or the change would leave a live agent with no calendar or live form (`goal_required`).
- `422`: Refused by a rule (`unprocessable`, `idempotency_key_reused`).
- `429`: Rate limited (`rate_limited`) or a monthly allowance used (`quota_exceeded`); see Retry-After.

## Changes

- **2026-10-20** `f93b0bcb454a`: 24 info
  - added the optional property `feature` to the response with the `400` status
  - added the optional property `feature` to the response with the `401` status
  - added the optional property `feature` to the response with the `402` status
  - added the optional property `feature` to the response with the `403` status
  - …20 more

[Operation history](https://skmtc.dev/meetdarwin/apis/darwin-api/changes/chat/sessions/post.md)

---

[API](https://skmtc.dev/meetdarwin/apis/darwin-api.md) · [All operations](https://skmtc.dev/meetdarwin/apis/darwin-api/llms.txt) · [OpenAPI document](https://skmtc.dev/meetdarwin/apis/darwin-api/revisions/f93b0bcb454a?raw)