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

# SDK Callback Flow

> Guide to understand the response flow of the SDK

### 1. SDK Initialization Flow

The following diagram illustrates the initialization sequence for Otpless SDK.

<img src="https://mintcdn.com/otpless-96/MG5MLCTUP00EUtvA/images/sdk-init-flow.png?fit=max&auto=format&n=MG5MLCTUP00EUtvA&q=85&s=7e8efbc709afaa22413f50b61945a71d" width="1607" height="1496" data-path="images/sdk-init-flow.png" />

### 2. Headless Authentication Flow (SNA)

The following diagram illustrates the authentication sequence for Otpless SDK.

<img src="https://mintcdn.com/otpless-96/MG5MLCTUP00EUtvA/images/android-auth-flow1.png?fit=max&auto=format&n=MG5MLCTUP00EUtvA&q=85&s=51f9b75c88af0a72cbfc8bc069e69310" width="3840" height="3598" data-path="images/android-auth-flow1.png" />

### 3. Headless Authentication Flow (OTP)

The following diagram illustrates the authentication sequence for Otpless SDK.

<img src="https://mintcdn.com/otpless-96/MG5MLCTUP00EUtvA/images/android-auth-flow2.png?fit=max&auto=format&n=MG5MLCTUP00EUtvA&q=85&s=5335976f826669f5d137a18ee5cfdd94" width="2587" height="3840" data-path="images/android-auth-flow2.png" />