# Set a simulated calendar's busy times (/docs/api-reference/scheduling-calendars/set-scheduling-simulated-busy)

Sandbox environments only: test how bookings react to a busy calendar.

`PUT https://api.coss.com/v1/scheduling/hosts/{host}/simulated_busy`

Authenticate with your API key as a bearer token (`Authorization: Bearer coss_test_…`). Responses are JSON with snake_case fields; errors are `{ error: { type, code, message, param?, issues?, request_id } }` (https://coss.com/docs/api-reference/errors.md).

## Path parameters

- `host` (string, required): The host's id or uid.

## Request body

- `intervals` (object[], required, at most 500 items)
  - `start` (string, required): An ISO 8601 instant with an offset.
  - `end` (string, required): An ISO 8601 instant with an offset.

## Example request

TypeScript (the `coss` package):

```ts
import { Coss } from "coss";

const coss = new Coss({
  apiKey: process.env.COSS_API_KEY,
  baseUrl: "https://api.coss.com",
});

const { data, error } = await coss.scheduling.calendars.setSimulatedBusy({
  value: "host_01kd2m9a0b1c2d3e4f5g6h7j8m",
}, {
  intervals: [
    {
      start: "2027-01-04T15:00:00.000Z",
      end: "2027-01-04T16:00:00.000Z",
    },
  ],
});
```

HTTP:

```sh
curl -X PUT "https://api.coss.com/v1/scheduling/hosts/host_01kd2m9a0b1c2d3e4f5g6h7j8m/simulated_busy" \
  -H "Authorization: Bearer $COSS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "intervals": [
    {
      "start": "2027-01-04T15:00:00.000Z",
      "end": "2027-01-04T16:00:00.000Z"
    }
  ]
}'
```

## Response 204

Set.

## Errors

- `400`: The body is not valid JSON (`invalid_json`). Also when the `Coss-Version` header names an unknown API version (`invalid_api_version`).
- `401`: The API key is missing, invalid, revoked or expired (`authentication_error`).
- `403`: The API key lacks the permission this endpoint needs (`permission_error`), or its organization is suspended (`organization_suspended`).
- `404`: Nothing with this id or uid exists in the environment (`not_found`).
- `415`: The body is not sent as `application/json` (`unsupported_media_type`).
- `422`: The request failed validation (`validation_error`, see `issues`), or can't be done: see `code`.
- `429`: Too many requests with this API key (`rate_limited`), or too many requests with invalid keys from this address (`too_many_failed_authentications`). Retry after `Retry-After` seconds. Successful responses carry `RateLimit-Limit`, `RateLimit-Remaining` and `RateLimit-Reset` (seconds until the limit is fully restored).
- `500`: Unexpected server error (`api_error` / `internal_error`).
- `503`: The API key could not be verified right now; retry (`service_unavailable`).