Mobile System Design and API Design of Stock Trading App
Explore the detailed mobile system design of a stock trading app, focusing on architecture patterns like MVVM-C, API design with idempotency keys, and real-time market data integration. Understand how to build secure, low-latency trading features through layered components, dependency injection, and WebSocket communication. This lesson helps you apply architectural decisions to design performant and reliable mobile financial applications.
As we transition from architectural considerations toward concrete System Design, it becomes essential to understand how these foundational decisions guide our frontend implementation. Previously established choices, such as adopting MVVM-C for architecture, utilizing the coordinator pattern for secure navigation, leveraging dependency injection for modularity, and implementing dual-channel communication (WebSocket and REST), now form the blueprint for designing the mobile app.
In this lesson, we will explore the stock trading app's System Design in detail, building directly upon the design decisions made in the previous lesson. We will also cover the critical APIs and their endpoints required for efficient, low-latency, and financially secure communication with the backend.
System Design of stock trading app
A well-defined architecture is critical in mobile System Design, particularly when dealing with high-frequency financial data. Layered patterns like MVVM-C efficiently organize responsibilities, but their true strength emerges when they coordinate with local caching tiers for instant responsiveness and backend services for real-time market data. This equilibrium ensures the application handles volatile markets gracefully, queues offline orders safely, and stays synchronized without choking the device's UI thread.
In the System Design for a stock trading application, we will start with a high-level design that outlines the core building blocks, illustrating how the mobile frontend connects to backend trading layers, and how transactional data flows end-to-end. Once this foundation is established, we will move into the detailed design, which breaks down internal mobile components, state management, and performance optimizations. This layered approach demonstrates architectural fluency in interviews by showing your ability to scale your explanation from a bird's-eye view down to component-level interactions.
Let’s first discuss the high-level System Design to establish a solid architectural overview.
High-level mobile System Design of stock trading app
At a high-level design, as illustrated below, when a trader opens the mobile app, the interaction begins directly with the View. ...