# Read Heart Rate via WebSocket

This method allows reading the heart rate of the user in real-time. The WebSocket connection can be interrupted at any point in time, make sure to have retry logic with backoff.

**Request**

<table><thead><tr><th width="197">name</th><th>value</th></tr></thead><tbody><tr><td>url</td><td><code>wss://dev.pulsoid.net/api/v1/data/real_time</code></td></tr><tr><td>scope</td><td><code>data:heart_rate:read</code></td></tr></tbody></table>

**Authentication**

Provide your OAuth2 Bearer token using one of the following methods:

| Method          | Example                                                               |
| --------------- | --------------------------------------------------------------------- |
| Query parameter | `wss://dev.pulsoid.net/api/v1/data/real_time?access_token=YOUR_TOKEN` |
| Header          | `Authorization: Bearer YOUR_TOKEN`                                    |

**Query Parameters explained:**

<table><thead><tr><th width="186">name</th><th width="103">type</th><th>description</th></tr></thead><tbody><tr><td>access_token</td><td>string</td><td>OAuth2 access token (alternative to Authorization header)</td></tr></tbody></table>

**Websocket URL Request Example**

```url
wss://dev.pulsoid.net/api/v1/data/real_time?access_token=8c4da3ce-7ed7-4a19-a1f1-058498661e45
```

**WebSocket Message Example**

```json
{
  "measured_at": 1625310655000,
  "data": {
    "heart_rate": 40
  }
}
```

**Websocket URL Request Example With response\_mode=text\_plain\_only\_heart\_rate**

```uri
wss://dev.pulsoid.net/api/v1/data/real_time?access_token=8c4da3ce-7ed7-4a19-a1f1-058498661e45&response_mode=text_plain_only_heart_rate
```

**WebSocket Message Example With response\_mode=text\_plain\_only\_heart\_rate**

```json
123
```

***

#### JavaScript / TypeScript

For JavaScript and TypeScript applications, use the official [`@pulsoid/socket`](https://www.npmjs.com/package/@pulsoid/socket) library instead of managing WebSocket connections manually. It provides auto-reconnection with exponential backoff, typed events, and zero dependencies.

```bash
npm install @pulsoid/socket
```

```javascript
import PulsoidSocket from '@pulsoid/socket';

const socket = PulsoidSocket.create('YOUR_TOKEN');

socket.on('heart-rate', (data) => {
  console.log(`${data.heartRate} BPM`);
});

await socket.connect();
```

See the [GitHub repository](https://github.com/pulsoid-oss/pulsoid-socket) for full documentation and configuration options.