> ## Documentation Index
> Fetch the complete documentation index at: https://omni.fireflo.au/llms.txt
> Use this file to discover all available pages before exploring further.

# POST /v1/conversations/{contact_id}/reply

> Reply in a conversation, on the channel named or where a reply goes by default.

Replies in a conversation, on the channel you name or where a reply goes by default (see [GET /v1/conversations/`{contact_id}`](/api-reference/conversations/get)). It is screened like a reply typed in the Inbox: refused with `not_permitted` when the person's consent doesn't allow it, and with `channel_closed` when the channel can't take typed text now. An AI agent on the conversation steps back, as when a person replies.

<Note>Needs the `conversations:write` scope.</Note>

## Path parameters

| Field | Type | Required | Notes |
| :- | :- | :- | :- |
| `contact_id` | string | Yes | The person's contact id: it names their conversation. |

## Body

| Field | Type | Required | Notes |
| :- | :- | :- | :- |
| `text` | string | Yes | The reply, up to 4096 characters. |
| `channel` | string | No | A channel this account has, e.g. `sms`. Left out, the default reply channel. |

Send an `Idempotency-Key` header to make a retry safe: the same key with the same body is answered once, and the first answer repeated (with `Idempotent-Replayed: true`).

## Request

<CodeGroup>
  ```bash cURL theme={null}
  curl -X POST https://api.fireflo.au/v1/conversations/3f6b2a1e-8c4d-4e2a-9b7f-5d1c0e8a9f42/reply \
    -H "Authorization: Bearer $OMNI_API_KEY" \
    -H "Content-Type: application/json" \
    -H "Idempotency-Key: reply-a1042-1" \
    -d '{
      "text": "It's with the courier and arrives tomorrow."
    }'
  ```

  ```python Python theme={null}
  import os

  import requests

  response = requests.post(
      "https://api.fireflo.au/v1/conversations/3f6b2a1e-8c4d-4e2a-9b7f-5d1c0e8a9f42/reply",
      headers={
          "Authorization": f"Bearer {os.environ['OMNI_API_KEY']}",
          "Idempotency-Key": "reply-a1042-1",
      },
      json={
          "text": "It's with the courier and arrives tomorrow.",
      },
  )
  print(response.status_code, response.json())
  ```

  ```javascript Node theme={null}
  const response = await fetch("https://api.fireflo.au/v1/conversations/3f6b2a1e-8c4d-4e2a-9b7f-5d1c0e8a9f42/reply", {
    method: "POST",
    headers: {
      Authorization: `Bearer ${process.env.OMNI_API_KEY}`,
      "Content-Type": "application/json",
      "Idempotency-Key": "reply-a1042-1",
    },
    body: JSON.stringify({
      "text": "It's with the courier and arrives tomorrow."
    }),
  });
  console.log(response.status, await response.json());
  ```
</CodeGroup>

## Response

`201 Created` — the message sent. Its author is the key that sent it.

```json theme={null}
{
  "id": "cm_918455",
  "channel": "whatsapp",
  "direction": "outbound",
  "to": "+919876543210",
  "from": "+911140001234",
  "status": "queued",
  "text": "It's with the courier and arrives tomorrow.",
  "error": "",
  "campaign": null,
  "created": "2026-10-05T09:15:40.208113+00:00",
  "status_at": null,
  "author": {
    "type": "system",
    "name": "API · Order service"
  },
  "media_url": null
}
```

## Errors

Every refusal is `{"error": {"code", "message", "field"}}`; `field` is there when one input is at fault.

| Status | Error code | When |
| :- | :- | :- |
| 404 | `not_found` | No conversation has that id on this account. |
| 400 | `invalid_request` | `text` is missing or too long, or `channel` isn't one this account has (`field` names it). |
| 409 | `channel_closed` | The channel can't take typed text now — WhatsApp's 24-hour window has closed, say. |
| 409 | `not_permitted` | The person's consent doesn't allow a message now. |
| 409 | `channel_refused` | The channel didn't take it; the message says why. |
| 400 | `invalid_json` | The body isn't valid JSON. |
| 403 | `scope_missing` | The key doesn't have the `conversations:write` scope. |

Any request can also be refused for its key, its account or its rate (`key_required`, `invalid_key`, `account_suspended`, `plan_excludes_api`, `address_not_allowed`, `rate_limited`); see [the overview](/api-reference/overview).


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.