# Get flag updates

By default, SDKs check for updates to your flag logic in the background. When you save and activate a new commit from the Hypertune UI, SDKs will fetch your new flag logic and use it on the next flag evaluation.

You can change the frequency at which the SDK checks for updates by setting `initDataRefreshIntervalMs` in your `createSource` options:

{% tabs %}
{% tab title="TypeScript (Server)" %}
{% code title="src/lib/getHypertune.ts" %}
```typescript
import { createSource } from "../generated/hypertune";

const hypertuneSource = createSource({
  token: process.env.HYPERTUNE_TOKEN!,
  initDataRefreshIntervalMs: 5_000,
});

export default async function getHypertune() {
  // Get flag updates in serverless environments
  // await hypertuneSource.initIfNeeded();

  return hypertuneSource.root({
    args: {
      context: {
        environment:
          process.env.NODE_ENV === "development"
            ? "development"
            : "production",
        user: { id: "1", name: "Test", email: "hi@test.com" },
      },
    },
  });
}
```
{% endcode %}
{% endtab %}

{% tab title="TypeScript (Browser)" %}
{% code title="src/components/AppHypertuneProvider.tsx" %}
```tsx
import { HypertuneProvider } from "../generated/hypertune.react";

export default function AppHypertuneProvider({
  children,
}: {
  children: React.ReactNode;
}) {
  return (
    <HypertuneProvider
      createSourceOptions={{
        token: import.meta.env.VITE_HYPERTUNE_TOKEN!,
        initDataRefreshIntervalMs: 5_000,
      }}
      rootArgs={{
        context: {
          environment:
            process.env.NODE_ENV === "development"
              ? "development"
              : "production",
          user: { id: "1", name: "Test", email: "hi@test.com" },
        },
      }}
    >
      {children}
    </HypertuneProvider>
  );
}
```
{% endcode %}
{% endtab %}

{% tab title="Python" %}
```python
import generated.hypertune as hypertune

root_node = hypertune.create_source(
    init_data_refresh_interval_ms=5_000
).root({
    "context": {
        "environment": "development",
        "user": {
            "id": "test_id",
            "name": "Test",
            "email": "hi@test.com",
        }
    }
})
root_node.wait_for_initialization()
```
{% endtab %}

{% tab title="Rust" %}
```rust
use hypertune::CreateOptions;

mod hypertune;

fn main() {
    let root_node = hypertune::initialize_hypertune(
        hypertune::VariableValues {},
        Some(CreateOptions {
            init_data_refresh_interval_ms: 5_000,
            ..Default::default()
        })
    )
    .unwrap()
    .root(hypertune::RootArgs {
        context: hypertune::Context {
            environment: hypertune::Environment::DEVELOPMENT,
            user: hypertune::User {
                id: "test_id".to_string(),
                name: "Test".to_string(),
                email: "test@test.com".to_string(),
            },
        },
    });
    root_node.wait_for_initialization();
}
```
{% endtab %}

{% tab title="Go" %}
<pre class="language-go"><code class="lang-go"><strong>package main
</strong>
import (
	"fmt"
	"log"
	"os"
	"time"

	sdk "github.com/hypertunehq/hypertune-go"
	// Update to your project path.
	"github.com/myTeam/myProject/pkg/hypertune"
)

func main() {
	var token = os.Getenv("HYPERTUNE_TOKEN")
	source, err := hypertune.CreateSource(
		&#x26;token,
		sdk.WithInitDataRefreshInterval(5*time.Second),
	)
	if err != nil {
		panic(err)
	}
	defer source.Close()
	
	source.WaitForInitialization()
	
	rootNode := source.Root(hypertune.RootArgs{
		Context: hypertune.Context{
			Environment: hypertune.Development,
			User: hypertune.User{
				Id:         "test_id",
				Name:       "Test",
				Email:      "hi@test.com",
			},
		},
	})
}
</code></pre>
{% endtab %}
{% endtabs %}

You can disable checking for updates by setting the `shouldRefreshInitData` option to `false`:

{% tabs %}
{% tab title="TypeScript (Server)" %}
{% code title="src/lib/getHypertune.ts" %}
```typescript
import { createSource } from "../generated/hypertune";

const hypertuneSource = createSource({
  token: process.env.HYPERTUNE_TOKEN!,
  shouldRefreshInitData: false,
});

export default async function getHypertune() {
  // Get flag updates in serverless environments
  // await hypertuneSource.initIfNeeded();

  return hypertuneSource.root({
    args: {
      context: {
        environment:
          process.env.NODE_ENV === "development"
            ? "development"
            : "production",
        user: { id: "1", name: "Test", email: "hi@test.com" },
      },
    },
  });
}
```
{% endcode %}
{% endtab %}

{% tab title="TypeScript (Browser)" %}
{% code title="src/components/AppHypertuneProvider.tsx" %}
```tsx
import { HypertuneProvider } from "../generated/hypertune.react";

export default function AppHypertuneProvider({
  children,
}: {
  children: React.ReactNode;
}) {
  return (
    <HypertuneProvider
      createSourceOptions={{
        token: import.meta.env.VITE_HYPERTUNE_TOKEN!,
        shouldRefreshInitData: false,
      }}
      rootArgs={{
        context: {
          environment:
            process.env.NODE_ENV === "development"
              ? "development"
              : "production",
          user: { id: "1", name: "Test", email: "hi@test.com" },
        },
      }}
    >
      {children}
    </HypertuneProvider>
  );
}
```
{% endcode %}
{% endtab %}

{% tab title="Python" %}
```python
import generated.hypertune as hypertune

root_node = hypertune.create_source(
    init_data_refresh_interval_ms=0
).root({
    "context": {
        "environment": "development",
        "user": {
            "id": "test_id",
            "name": "Test",
            "email": "hi@test.com",
        }
    }
})
root_node.wait_for_initialization()
```
{% endtab %}

{% tab title="Rust" %}
```rust
use hypertune::CreateOptions;

mod hypertune;

fn main() {
    let root_node = hypertune::initialize_hypertune(
        hypertune::VariableValues {},
        Some(CreateOptions {
            init_data_refresh_interval_ms: 0,
            ..Default::default()
        })
    )
    .unwrap()
    .root(hypertune::RootArgs {
        context: hypertune::Context {
            environment: hypertune::Environment::DEVELOPMENT,
            user: hypertune::User {
                id: "test_id".to_string(),
                name: "Test".to_string(),
                email: "test@test.com".to_string(),
            },
        },
    });
    root_node.wait_for_initialization();
}
```
{% endtab %}

{% tab title="Go" %}
<pre class="language-go"><code class="lang-go"><strong>package main
</strong>
import (
	"fmt"
	"log"
	"os"

	sdk "github.com/hypertunehq/hypertune-go"
	// Update to your project path.
	"github.com/myTeam/myProject/pkg/hypertune"
)

func main() {
	var token = os.Getenv("HYPERTUNE_TOKEN")
	source, err := hypertune.CreateSource(
		&#x26;token,
		sdk.WithInitDataRefreshInterval(0),
	)
	if err != nil {
		panic(err)
	}
	defer source.Close()
	
	source.WaitForInitialization()
	
	rootNode := source.Root(hypertune.RootArgs{
		Context: hypertune.Context{
			Environment: hypertune.Development,
			User: hypertune.User{
				Id:         "test_id",
				Name:       "Test",
				Email:      "hi@test.com",
			},
		},
	})
}
</code></pre>
{% endtab %}
{% endtabs %}

## Manually check for flag updates

You can manually check for flag updates with the `initIfNeeded` method:

```typescript
import { createSource } from "../generated/hypertune";

const hypertuneSource = createSource({
  token: process.env.HYPERTUNE_TOKEN!,
  initDataRefreshIntervalMs: 5_000,
});

export default async function getHypertune() {
  await hypertuneSource.initIfNeeded(); // Check for flag updates

  return hypertuneSource.root({
    args: {
      context: {
        environment:
          process.env.NODE_ENV === "development"
            ? "development"
            : "production",
        user: { id: "1", name: "Test", email: "hi@test.com" },
      },
    },
  });
}
```

When using `initIfNeeded`, the `initDataRefreshIntervalMs` option specifies the minimum time between initialization requests.

For example, if you set this to `5_000`, `initIfNeeded` will only trigger a new initialization request if the last one was over 5 seconds ago.

So you can await `initIfNeeded` on every backend request to ensure flag values are fresh while minimizing network latency and bandwidth.

This is particularly useful in [serverless and edge environments](serverless-environments) like Vercel deployments, Cloudflare Workers, AWS Lambdas, etc, where background SDK tasks like fetching updates aren't guaranteed to execute.

## Subscribe to flag updates

You can add and remove listeners to be notified of updates with:

```typescript
hypertune.addUpdateListener(listener: (newStateHash: string) => void)
hypertune.removeUpdateListener(listener: (newStateHash: string) => void)
```

You can also get the current state hash with:

```typescript
hypertune.getStateHash(): string | null
```
