# Join a public channel

> The app adds itself to a public channel. Joining twice changes nothing.

**POST** `/api/public/apps/v1/channels/{channelId}/join`

Needs the `channels:join` permission.

The app adds itself to a public channel. Joining twice changes nothing. A private channel can only be joined when a person adds the app to it.

## Parameters

| Name | In | Required | Meaning |
| --- | --- | --- | --- |
| `channelId` | path | yes | A public channel of the workspace. |

## Example

**curl**

```sh
curl -X POST "https://amedeus.app/api/public/apps/v1/channels/<channel id>/join" \
  -H "Authorization: Bearer $TOKEN"
```

**JavaScript**

```js
const response = await fetch("https://amedeus.app/api/public/apps/v1/channels/<channel id>/join", {
  method: "POST",
  headers: { Authorization: `Bearer ${process.env.TOKEN}` },
});
const result = await response.json(); // { ok: true, … } or { ok: false, error, message }
```

**Python**

```python

request = urllib.request.Request(
    "https://amedeus.app/api/public/apps/v1/channels/<channel id>/join",
    headers={
        "Authorization": f"Bearer {os.environ['TOKEN']}",
        "User-Agent": "my-app/1.0",
    },
    method="POST",
)
with urllib.request.urlopen(request) as response:
    result = json.load(response)  # a 4xx or 5xx raises urllib.error.HTTPError
```

## Response

| Field | Type | Required | Meaning |
| --- | --- | --- | --- |
| `ok` | `true` | yes |  |

```json
{
  "ok": true
}
```

## Errors

Failures answer `{ "ok": false, "error": "<code>", "message": "…" }`; see [Errors](/reference/errors/).

- `401`: The token is missing, wrong or revoked.
- `403`: A missing scope (the message names it), or a channel the app isn't in.
- `404`: The message or channel doesn't exist.
- `429`: Slow down; `Retry-After` says for how many seconds.