---
title: "Core Management API"
source_url: https://docs.rapyd.net/en/core-management-api.html
lang: en
---

# Core Management API

### `startCore`

Call at app startup. Launches the Core application in the background, ensuring it is ready when the first transaction is needed. Avoids delays on the first payment.

```java

Api.startCore(context);

// Optionally provide your app's name for diagnostic logs
Api.startCore(context, "MyApp");
```

### `requestConfig`

Request the current terminal configuration. Core broadcasts `CONFIG_RESULT_ACTION` with a `Config` JSON object.

```java

Api.requestConfig(context);
```

Core also sends `CONFIG_RESULT_ACTION` automatically at startup. See [Configuration Fields](https://docs.rapyd.net/en/configuration-fields.md "Configuration Fields") for the full field list.

### `updateParameter`

Update one or more runtime settings. Core reloads its configuration after applying the changes.

```java

HashMap<String, String> params = new HashMap<>();
params.put(Parameters.PRINT_RECEIPT_SETTING, "true");
params.put(Parameters.AUDIO_SETTING, "MUTE");   // AUDIO | SILENT_KEYBOARD | MUTE
params.put(Parameters.THEME_SETTING, "DARK");   // DARK | LIGHT

Api.updateParameter(context, params);
```

Supported settings keys: `PRINT_RECEIPT_SETTING`, `USE_SIGNATURE_ON_SCREEN_SETTING`, `AUDIO_SETTING`, `THEME_SETTING`, `MERCHANT_RECEIPT_SETTING`.

### `switchMerchant`

Switch the active merchant. Only applicable when multi-merchant is configured. The `merchantId` value comes from `MerchantConfig.getId()`, obtained via `requestConfig` or `getAvailableMerchants`.

```java

Api.switchMerchant(context, merchantId);
```

> **Note:**
>
> If the supplied `merchantId` does not exist on the device, the switch is silently ignored.

### `getAvailableMerchants`

Fetch the list of merchants configured on the device. Result is broadcast as `ACTION_GET_AVAILABLE_MERCHANTS_RESULT`.

```java

Api.getAvailableMerchants(context);

// In your receiver:
case Messages.ACTION_GET_AVAILABLE_MERCHANTS_RESULT: {
    String json = intent.getStringExtra(Messages.AVAILABLE_MERCHANTS_RESULT);
    List<MerchantResult> merchants = WrapperUtils.getMerchantsFromJson(json);
    break;
}
```

### `updateLanguage`

Change the device system language. This affects the language used in Core's own UI and receipts.

```java

Api.updateLanguage(context, "sv_SE");
```

### `updateMerchantPassword`

Update the PIN/password for a specific merchant.

```java

Api.updateMerchantPassword(context, merchantId, newPassword);
```

### `cycleKeys`

Cycle the terminal encryption keys.

```java

Api.cycleKeys(context);

// With locale override
HashMap<String, String> params = new HashMap<>();
params.put(Parameters.LOCALE, "en_GB");
Api.cycleKeys(context, params);
```

### `shutdownCore`

Shut down the Core application.

```java

Api.shutdownCore(context);
```