BlackBull Markets: Mobile Trading App

The Problem

BlackBull Markets is a regulated forex and CFD broker based in New Zealand. They had a strong web trading platform but no mobile app for retail clients. Their competitors — including eToro and Robinhood — had already captured mobile-first traders.

The requirements were demanding: real-time price feeds for 80+ instruments, enterprise-grade security (biometric auth and encrypted session tokens), a candlestick charting library capable of handling rapid tick data, and a UX that felt as polished as the consumer fintech apps their clients were already using.

What I Built

I built the app end-to-end in Flutter. The most technically demanding part was the WebSocket integration for live price feeds. The solution maintains a persistent connection, handles reconnections gracefully, and updates the UI in real time without visible jank even during high-frequency tick events.

Security was a priority. Biometric authentication (Face ID on iOS, fingerprint on Android) was implemented using a native plugin layer to ensure compliance with platform security standards. Session tokens are stored in the device secure enclave, not in shared preferences or local storage.

The portfolio dashboard shows real-time P&L per position, account balance, margin levels, and open orders — all updating live from the WebSocket feed. Custom candlestick charts were built to handle multiple timeframes without performance degradation on lower-end Android devices.

The Result

The app launched on both iOS and Android and has maintained 99.9% uptime since release. BlackBull now serves mobile traders across 80+ markets with sub-100ms price feed latency.

Building with Flutter meant BlackBull got two fully native-feeling apps from a single codebase. Every feature ships to iOS and Android simultaneously, with no feature gap between platforms.

Tech Stack