> ## 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/calendar/appointments

> Book a contact into a free time of a booking type.

Books a contact into a free time of a booking type — one from [GET /v1/calendar/free-times](/api-reference/calendar/free-times). The time must still be free: a teammate has one appointment at a time, prep time included. The appointment is booked with `source` `api`, and the contact is sent the account's confirmation and reminders, as when the team books.

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

## Body

| Field | Type | Required | Notes |
| :- | :- | :- | :- |
| `contact` | string | Yes | The contact's id. |
| `booking_type` | integer | Yes | The booking type's id. It must be switched on. |
| `starts_at` | string | Yes | When it starts, with its offset: `2026-10-08T10:30:00+05:30`. A free start for the booking type. |
| `staff` | string | No | The email of the teammate to book. Left out, the first one free then — the booking type's default teammate first. |
| `status` | string | No | `confirmed` (the default) or `requested`. |
| `mode` | string | No | `online` or `physical`, for a booking type whose mode is `either` — the account's default when left out. Other booking types keep their own mode. |
| `location` | string | No | Where, for an in-person appointment. Up to 255 characters. Left out, the booking type's place, the teammate's, or the account's default. |
| `meeting_link` | string | No | The link, for an online appointment. Up to 500 characters. Left out, the booking type's link or the teammate's. |
| `notes` | string | No | The team's notes. Up to 5,000 characters. |
| `deal` | string | No | The id of a deal it belongs to, with Pipelines. |

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/calendar/appointments" \
    -H "Authorization: Bearer $OMNI_API_KEY" \
    -H "Content-Type: application/json" \
    -H "Idempotency-Key: book-ravi-8oct-1030" \
    -d '{
    "contact": "3f6b2a1e-8c4d-4e2a-9b7f-5d1c0e8a9f42",
    "booking_type": 3,
    "starts_at": "2026-10-08T10:30:00+05:30",
    "staff": "priya@acme.in",
    "mode": "online",
    "notes": "Salaried, looking at a ₹45 lakh loan. Bring Form 16."
  }'
  ```

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

  import requests

  response = requests.post(
      "https://api.fireflo.au/v1/calendar/appointments",
      headers={
          "Authorization": f"Bearer {os.environ['OMNI_API_KEY']}",
          "Idempotency-Key": "book-ravi-8oct-1030",
      },
      json={
          "contact": "3f6b2a1e-8c4d-4e2a-9b7f-5d1c0e8a9f42",
          "booking_type": 3,
          "starts_at": "2026-10-08T10:30:00+05:30",
          "staff": "priya@acme.in",
          "mode": "online",
          "notes": "Salaried, looking at a ₹45 lakh loan. Bring Form 16."
      },
  )
  print(response.status_code, response.json())
  ```

  ```javascript Node theme={null}
  const response = await fetch("https://api.fireflo.au/v1/calendar/appointments", {
    method: "POST",
    headers: {
      Authorization: `Bearer ${process.env.OMNI_API_KEY}`,
      "Content-Type": "application/json",
      "Idempotency-Key": "book-ravi-8oct-1030",
    },
    body: JSON.stringify({
      "contact": "3f6b2a1e-8c4d-4e2a-9b7f-5d1c0e8a9f42",
      "booking_type": 3,
      "starts_at": "2026-10-08T10:30:00+05:30",
      "staff": "priya@acme.in",
      "mode": "online",
      "notes": "Salaried, looking at a ₹45 lakh loan. Bring Form 16."
    }),
  });
  console.log(response.status, await response.json());
  ```
</CodeGroup>

## Response

`201 Created` — the appointment, as [GET /v1/calendar/appointments/\{appointment\_id}](/api-reference/calendar/get-appointment) shows it, without its history. It also sends `appointment.booked` to your [webhook endpoints](/developers/webhooks).

```json theme={null}
{
  "id": "5b0e7d3c-9a2f-4c61-8e47-1f3a6c9d2b84",
  "title": "Home loan consultation",
  "status": "confirmed",
  "booking_type": {
    "id": 3,
    "name": "Home loan consultation"
  },
  "contact": {
    "id": "3f6b2a1e-8c4d-4e2a-9b7f-5d1c0e8a9f42",
    "name": "Ravi Kumar",
    "phone": "+919876500101"
  },
  "staff": {
    "name": "Priya Sharma",
    "email": "priya@acme.in"
  },
  "starts_at": "2026-10-08T10:30:00+05:30",
  "ends_at": "2026-10-08T11:00:00+05:30",
  "mode": "online",
  "location": "",
  "meeting_link": "https://meet.google.com/kfr-ptqw-xya",
  "notes": "Salaried, looking at a ₹45 lakh loan. Bring Form 16.",
  "source": "api",
  "deal": null,
  "created_at": "2026-10-06T04:12:04.512903+00:00",
  "updated_at": "2026-10-06T04:12:04.512903+00:00"
}
```

## Errors

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

| Status | Error code | When |
| :- | :- | :- |
| 400 | `invalid_request` | A field is wrong — `field` names it: no `contact`, an unknown or switched-off `booking_type`, a `starts_at` without its offset, a `staff` who isn't in your team or doesn't take this booking type, a `status` other than `confirmed` or `requested`, an unknown `deal`, or text that is too long. |
| 409 | `slot_taken` | That time isn't free (any more) — pick another from the free times. |
| 409 | `invalid_state` | Appointments are switched off in the account's Calendar settings. |
| 404 | `module_off` | The account's plan doesn't include Calendar. |
| 403 | `scope_missing` | The key doesn't have the `calendar: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).


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