System Design Practice: Designing an ATM

System design interviews and real-world software engineering require a deep understanding of how hardware, software, and secure networks interact. Designing an ATM is a classic architectural challenge that tests your ability to handle concurrency, strict data consistency, and fail-safe operations. This course guides you through the entire design process, from initial requirements gathering to final architectural decisions. You will start by learning the fundamental terminology, basic hardware-software communication concepts, and core security protocols. Next, you will explore how to manage distributed state, ensure transactional integrity, and handle network failures gracefully. We also cover modern cloud integration and API gateway patterns to ensure your design aligns with contemporary engineering practices. What you'll learn: - Understand the core functional and non-functional requirements of an ATM system - Design secure APIs and communication protocols between the physical terminal and banking servers - Apply transactional database concepts to prevent double-spending and ensure strict consistency - Configure fail-safe mechanism strategies for handling network disconnects mid-transaction - Map out the high-level architecture including load balancers, database replicas, and security layers - Analyze edge cases such as concurrent card usage and physical cash dispensing failures This course is structured as a progressive written guide, starting with foundational definitions before moving into detailed architectural blueprints and system flowcharts. It is designed for software developers, aspiring system architects, and students preparing for technical interviews. No prior system design experience is required, though a basic understanding of software development concepts is helpful. Dive in to build a solid foundation in secure, distributed system design.