---
title: "Cue App"
description: "Technical lead for a cross-platform numerology app on iOS, Android, and Web. 90% code sharing from a single codebase, 50% faster feature releases, and a 4-person team."
author: "Filipe Brito Ferreira (Senior Front-End Platform Engineer)"
canonical: https://www.fbritoferreira.com/projects/cue-app/
published: 2023
tags: ["React Native", "Next.js", "TypeScript", "Expo", "Firebase"]
image: https://cdn.fbritoferreira.com/images/cue-app-1920.webp
---

## What it is

Cue is a cross-platform numerology app that runs on iOS, Android, and Web from a single codebase.

## Numbers

- **90% code sharing** across iOS, Android, and Web
- **50% faster** feature releases vs platform-specific development
- **4-person team** with full technical ownership
- **3 platforms** from one codebase

## How it's built

React Native with Expo handles mobile, Next.js handles the web. The architecture keeps business logic and UI components shared, with thin platform-specific layers only where native capabilities require it.

The main technical choices:

- **Expo managed workflow** for simplified builds and over-the-air updates, no ejecting needed
- **Firebase** for the backend: real-time database, auth, and cloud functions
- **Shared component library** so the design system renders correctly everywhere
- **Feature flags** for gradual rollouts and A/B testing across platforms

## Running the team

I set the code quality standards, run reviews, and handle performance optimization across all three platforms. I also work with the product side on roadmap prioritization, making sure technical decisions line up with what the business actually needs.