Secure Authentication SDK
Android & iOS — Identity, Biometrics & Passwordless Login
As Lead Developer, we built an Android and iOS SDK, along with demonstration apps, for digital identity management. The solution offered several secure login methods — email, Google, Facebook, biometrics, Face ID and passwordless authentication.
PROJECT OVERVIEW
How the product was structured
The overview is split into context, platform, architecture, and stack so the delivery shape is easier to scan.
PRODUCT CONTEXT
The SDK gave client applications a ready-to-integrate identity layer: email, Google and Facebook login, biometric authentication with Touch ID and Face ID, and a FIDO2-based passwordless flow — all backed by modern OAuth 2.0 and PKCE security.
Stack snapshot
Core technologies used to ship and run the product.
QUICK BRIEF
What did we build for this identity SDK?
As Lead Developer, we built an Android and iOS SDK, along with demonstration apps, for digital identity management — offering email, Google, Facebook, biometric, Face ID and passwordless login. The project…
How it worked
The solution shipped as native Android (Kotlin, Java) and iOS (Swift) SDKs built with Clean Architecture, using Retrofit and Alamofire for networking. Identity flows were secured with OAuth 2.0 and PKCE, with a dedicated FIDO2 module enabling passwordless authentication and biometric login via Touch ID and Face ID. Bitrise handled continuous integration, and demo applications were published on Google Play and the App Store to support client evaluation and onboarding...
Engineering focus
- OAuth 2.0 and PKCE protocol implementation for secure identity flows
- FIDO2-based module for passwordless authentication
- Biometric integration — Touch ID and Face ID — across Android and iOS
What changed
- Simpler, more secure authentication for end users
- Easier integration of the identity system into client applications
- Improved SDK quality, documentation and delivery process
- Consistent support for Android and iOS journeys
ENGINEERING CHALLENGES
Where the complexity lived
These were the main constraints the product architecture had to solve before launch.
Challenge 01
Multiplatform SDK design — Android and iOS SDK development for consistent integration across client applications
Challenge 02
Modern secure protocols — implementing OAuth 2.0, PKCE, FIDO2 and secure identity management on both platforms
Challenge 03
Industrialization — continuous integration, documentation, demo applications and client support for smooth adoption
ENGINEERING RESPONSIBILITY
What our team owned
The delivery scope covered product engineering, supporting systems, and production readiness.
Developed the Android and iOS SDKs and demo applications
Integrated Google and Facebook login
Implemented OAuth 2.0 and PKCE protocols
Built a FIDO2 module for passwordless authentication
Integrated biometrics, Touch ID and Face ID
Improved asynchronous call handling and error management
Set up continuous integration with Bitrise
Wrote technical documentation and supported clients
Published the demo applications on Google Play and the App Store
KEY FEATURES
Capabilities that moved the needle
Multi-method login
Email, Google and Facebook sign-in alongside biometric login, all through a single SDK.
Passwordless authentication
A FIDO2-based module removing the need for passwords while keeping identity flows secure.
Biometrics
Touch ID and Face ID integration for fast, secure login across both platforms.
Secure by design
OAuth 2.0 and PKCE protocols underpinning every authentication flow.