> For the complete documentation index, see [llms.txt](https://docs.hackle.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.hackle.io/en/development-guide/http-api/api-track.md).

# Event Tracking

{% hint style="info" %}
The HTTP API can only be used in a server environment.
{% endhint %}

You can use the HTTP API to track events for a user.

Authentication is performed using the SDK Key.

* Add the SDK Key to the HTTP header as shown below.
* You can find the SDK Key in the Hackle Dashboard under [SDK Integration Info](https://dashboard.hackle.io/config/sdk-setting).

```http
X-HACKLE-API-KEY: {YOUR_SERVER_SDK_KEY}
```

### Request

```http
POST https://api.hackle.io/v1/track
```

#### Request Body

| Field | Type         | Required | Description                  |
| ----- | ------------ | -------- | ---------------------------- |
| event | Event object | O        | Event to track               |
| user  | User object  | O        | User who triggered the event |

**Event Object**

| Field      | Type   | Required | Description                                                         |
| ---------- | ------ | -------- | ------------------------------------------------------------------- |
| key        | string | O        | Event Key                                                           |
| value      | number | X        | Using the properties (Event Property) field is recommended instead. |
| properties | object | X        | Event Property key(string)-value(string)                            |

**User Object**

| Field       | Type   | Required | Description                                      |
| ----------- | ------ | -------- | ------------------------------------------------ |
| userId      | string | X        | User ID (Hackle ID can be used)                  |
| deviceId    | string | X        | Device ID (Hackle ID can be used)                |
| identifiers | object | X        | Custom identifier key(string)-value(string) pair |
| properties  | object | X        | User Property key(string)-value(string)          |

#### Example

```shell
curl -i -X POST \
  'https://api.hackle.io/v1/track' \
  -H 'X-HACKLE-API-KEY: YOUR_SDK_KEY_HERE' \
  -H 'Content-Type: application/json' \
  -d '{
    "event": {
      "key": "purchase",
      "properties": {
        "paymentMethod": "CARD",
        "discountAmount": 420
      }
    },
    "user": {
      "userId": "19285035",
      "deviceId": "ae2182e0",
      "identifiers": {
        "sessionId": "16930492542",
        "myCustomId": "ff01eae2"
      },
      "properties": {
        "grade": "GOLD",
        "age": 30,
        "isLogin": true
      }
    }
  }'
```

### Response

#### 200 OK

Returns a 200 response status for a successful request.

#### 400 Bad Request

Returns a 400 status for invalid request information.

#### 401 Unauthorized

Returns a 401 status when the `X-HACKLE-API-KEY` header value is missing or the SDK Key is invalid.


---

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