Shipaton 2025 - Day 4 - Sign In with Firebase is Ready
Day 4 of my Shipaton 2025 journey was all about completing the Firebase Authentication loop by adding Email/Password Sign In. I implemented a working Sign In flow, enabling existing users to log into the app - turning the project into a functional system that can differentiate between new and returning users.
Mantas Butenas
8/5/20251 min read
What I Built Today?
Today’s focus was on expanding my Android app’s authentication system by adding Email/Password Sign In using Firebase Authentication. Here’s what I accomplished:
✔️ Implemented Firebase Email/Password Sign In: Existing users can now log into their accounts using their credentials stored in Firebase.
✔️ Connected Sign In Form to Firebase: The Sign In button is now fully wired up to authenticate user credentials, ensuring that only valid accounts can access the app.
✔️ Verified End-to-End Authentication Flow: With both Sign Up and Sign In now working, the app has a complete loop for creating and logging into user accounts.
While the app doesn’t yet store or load user-specific progress, today’s milestone is a foundational step towards managing user sessions effectively.
What This Means for the App?
With both Sign Up and Sign In now implemented, the app can identify who is using it. This foundational capability might seem basic, but it’s the enabler for everything that makes an app feel personal - from saving user preferences to tailoring content.
Even though I haven’t yet connected user data or progress tracking, today’s work lays the infrastructure that allows the app to distinguish between a new visitor and a returning user.
Authentication is more than just a login screen - it’s the handshake that builds trust between the user and the product. This is the point where the app stops being a static interface and starts becoming a service designed around individual users.
Small Wins that Matter
There’s something uniquely satisfying about seeing an app evolve from a collection of screens into a working system. While today’s addition of Sign In doesn’t add new visual elements, it represents a behind-the-scenes win - one that turns UI mockups into an actual user system.
As an indie Android developer, these small, functional victories are what keep the momentum alive. Each invisible improvement is a building block that makes the product feel more alive and more real.