> 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/go.md).

# Go

## Add Dependency

[![](https://img.shields.io/github/v/release/hackle-io/hackle-go-sdk)](https://pkg.go.dev/github.com/hackle-io/hackle-go-sdk)

Add the SDK dependency.

```shell
go get github.com/hackle-io/hackle-go-sdk
```

## SDK Initialization

{% hint style="danger" %}
`hackle.Client` must be a singleton.

`HackleClient` manages state internally to distribute users to Variations immediately without network calls.\
This uses additional resources for that purpose.

Do not instantiate a new client for every request; instead, manage it as a single instance throughout the application lifecycle.
{% endhint %}

`hackle.Client` is the class that provides methods for using SDK features.

To use the SDK, you need to initialize `hackle.Client`.

#### Instantiation

Instantiate `hackle.Client` by passing the SDK Key.\
`hackle.Client` periodically synchronizes with the Hackle server as a background task to obtain the necessary information.

* You can find the SDK Key in [SDK Integration Info](https://dashboard.hackle.io/config/sdk-setting) located inside the Hackle Service Dashboard.

```go
import "github.com/hackle-io/hackle-go-sdk/hackle"

// YOUR_SERVER_SDK_KEY 자리에 SDK 키를 넣습니다.
hackleClient := hackle.NewClient(YOUR_SERVER_SDK_KEY, nil)
```

## Shutdown

You must call the `close()` method when the application shuts down.\
This releases resources in use and sends any remaining events.

{% hint style="danger" %}
If the application shuts down without calling `close()`, events may be lost.
{% endhint %}

```go
import "github.com/hackle-io/hackle-go-sdk/hackle"

hackleClient.Close()
```


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