The Device Risk SDK is the missing piece that makes the Prefill + Onboarding flow feel like one tap. It runs in your client app, collects device signals, and produces a diSessionToken that lets us perform Silent Network Authentication (SNA) — verifying the user's identity in the background, with no OTP step shown to the user. Without the SDK, every Prefill + Onboarding session falls back to a 6-digit OTP delivered over SMS, which adds friction and an extra step the user has to complete. With it, the device-trust signal is strong enough on most carrier networks for SNA to succeed silently — the user enters their name and phone number, we prefill the rest, and they're verified.
The SDK is available for Web (JavaScript), iOS (Swift), and Android (Kotlin), and it's only relevant when you're calling the Prefill and Onboarding endpoints directly from your own UI; the CRS widget bundles the SDK behavior internally and doesn't require you to install anything separately. Below you'll find platform-specific setup instructions, sample code for generating and forwarding the diSessionToken, and the rules about when to send it on which endpoints.
The SDK is only relevant for direct API integrations using the Prefill + Onboarding identity flow. When you build your own UI against the User API and call the Prefill and Onboarding endpoints, you must include diSessionToken on every Prefill and Onboarding request to enable Silent Network Authentication. See Identity Verification (Prefill + Onboarding) for the matching endpoints.
If diSessionToken is missing or invalid, the user is automatically routed through OTP fallback instead of SNA — your integration still works, it just shows the OTP step.
Not needed for the widget. If you embed the CRS widget, the widget handles all device-risk signals internally. You don't need to integrate the SDK yourself.
You'll receive your SDK Key during onboarding. The SDK ships for Web, iOS, Android, and React Native — pick the platforms you need.