> ## Documentation Index
> Fetch the complete documentation index at: https://docs.verifyyou.com/llms.txt
> Use this file to discover all available pages before exploring further.

# init()

> Optional. Set an appBase override once, for dev or staging builds.

## Signature

<CodeGroup>
  ```kotlin Android theme={null}
  fun initialize(appBase: String = VerifyYou.DEFAULT_APP_BASE)
  ```

  ```swift iOS theme={null}
  static func initialize(appBase: URL = defaultAppBase)
  ```

  ```ts React Native theme={null}
  function init(config?: InitConfig): void;

  interface InitConfig {
    appBase?: string;
  }
  ```
</CodeGroup>

Optional, on every platform. There is nothing else to configure: no key, ever, on any of the three SDKs. Skip calling this entirely if you are shipping against production.

## Options

<ParamField path="appBase" type="string" default="https://app.verifyyou.com">The hosted flow's own origin. Override it for a dev or staging build, the same as the browser SDK's `appBase`. It must be an `https` VerifyYou origin, or a local dev host. See Errors below for what an invalid value does.</ParamField>

## Errors

An invalid `appBase` is a developer mistake, and each platform reacts differently.

* Android throws `IllegalArgumentException`.
* React Native throws an `Error`. It checks the value in JavaScript, before the native SDK sees it.
* iOS in a debug build stops with an assertion failure.
* iOS in a release build ignores the value without any message and keeps the previous `appBase`. That is production unless you set a valid one earlier.

<Note>
  A release build on iOS never tells you that an override was ignored. A typo in a staging `appBase` runs against production. Check your override in a debug build first.
</Note>


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