Android SDK - OTPLESS

This page covers the integration of the OTPless Headless SDK on Android. The SDK accepts the requestId generated by the Create API, performs the authentication, and reports progress through callbacks. Your backend confirms the final result via the Status Check API.

Requirements

Requirement	Version
`compileSdk`	35
Minimum SDK	21
Kotlin	1.9.0+
Gradle	8.3.1+

Step 1: Add SDK dependency

Add the OTPLESS SDK to your app’s build.gradle:

implementation ("io.github.otpless-tech:otpless-headless-lite:latest_version")

Check the latest version of the SDK here. Make sure to synchronize your Gradle project to fetch the dependency.

Make sure your authentication channel is enabled on the OTPLESS dashboard.

Step 2: Initialize the SDK

Import OtplessSDK in your LoginActivity.kt:

import com.otpless.v2.android.sdk.main.OtplessSDK

Initialize the SDK depending on your app architecture:

LoginActivity — initialize in onCreate()
LoginFragment — initialize in onViewCreated()

lifecycleScope.launch(Dispatchers.IO) {
    OtplessSDK.initialize(
        APP_ID,
        this@LoginActivity,
        callback = this@LoginActivity::onOtplessResponse
    )
}

OtplessSDK.initialize(APP_ID, this, this::onOtplessResponse);

Replace APP_ID with your actual App ID from the OTPLESS dashboard.

Step 3: Start authentication with the requestId

Pass the requestId returned by the Create API to start():

val otplessRequest = OtplessRequest()
otplessRequest.requestId = "REQUEST_ID_FROM_API"

lifecycleScope.launch {
    OtplessSDK.start(request = otplessRequest, callback = ::onOtplessResponse)
}

Start polling the Status Check API from your backend immediately after calling start(). The SDK callback and the server status run in parallel.

Step 4: Handle callbacks

private fun onOtplessResponse(response: OtplessResponse) {
    OtplessSDK.commit(response)
    when (response.responseType) {
        ResponseTypes.SDK_READY -> {
            // SDK initialized successfully — enable your continue button
            // or proceed with user authentication.
        }
        ResponseTypes.FAILED -> {
            // SDK initialization failed
            if (response.statusCode == 5003) {
                // Please try to initialize the SDK again.
            }
        }
        ResponseTypes.INITIATE -> {
            // Authentication has been initiated
            if (response.statusCode != 200) {
                handleInitiateError(response)
            } else {
                // Authentication is in progress — show a loading state.
            }
        }
        ResponseTypes.ONETAP -> {
            // Final success response
        }
        ResponseTypes.AUTH_TERMINATED -> {
            // Auth could not complete. Emitted when pre-checks fail,
            // or when authentication was attempted and then failed/expired.
            // Treat as a terminal failure and rely on the Status Check API
            // for the exact error.
        }
    }
}

Callback reference

The SDK works in two steps — initialization and start() — and each step has its own set of callbacks.

Step 1: Initialization callbacks

Emitted when you initialize the SDK (Step 2).

Callback	Meaning
`SDK_READY`	SDK initialization completed.
`FAILED`	SDK failed to initialize (e.g. `statusCode 5003`).

Step 2: Start callbacks

Emitted after you invoke start() (Step 3).

Callback	State	Meaning
`INITIATE`	Non-terminal	Authentication is in progress after pre-checks pass.
`ONETAP`	Success — terminal	Authentication completed successfully. Returns `token` / `idToken`.
`AUTH_TERMINATED`	Failed — terminal	Emitted in two cases: (1) pre-checks failed → terminated directly; (2) authentication was initiated and then failed/expired.

AUTH_TERMINATED is a terminal failure. Always treat the Status Check API result as authoritative.

For the errorCode / statusCode values surfaced in SDK callbacks, see SDK Error Codes.

Next step

Status Check API

Confirm the authoritative auth status from your server.

​Requirements

​Step 1: Add SDK dependency

​Step 2: Initialize the SDK

​Step 3: Start authentication with the requestId

​Step 4: Handle callbacks

​Callback reference

​Step 1: Initialization callbacks

​Step 2: Start callbacks

​Next step

Status Check API

Requirements

Step 1: Add SDK dependency

Step 2: Initialize the SDK

Step 3: Start authentication with the requestId

Step 4: Handle callbacks

Callback reference

Step 1: Initialization callbacks

Step 2: Start callbacks

Next step