Modern security strategies rely on a principle known as defense in depth, which involves layering protections at multiple levels: network, application, and data. Authentication verifies a user’s identity, and best practices include implementing multi-factor authentication (MFA) to reduce the risk of unauthorized access. Authorization ensures that users and services have access only to the resources they are permitted to use, following the principle of least privilege.
To further protect data, systems should use encryption in transit (TLS/SSL protocols) and encryption at rest (securing stored data with technologies like AES). Additionally, using secure API gateways, rotating credentials regularly, logging security events, and performing routine audits are essential to maintaining a secure and resilient architecture.
With a strong understanding of the key considerations, it’s now important to explore the different types of System Design that guide how systems are structured based on their scale, complexity, and purpose.
Checkpoint: Functional vs. Nonfunctional Requirements at the Café#
To better grasp the crucial distinction between the functional and nonfunctional requirements of System Design, imagine you're preparing for the most sacred (and delicious) of morning rituals: brewing the perfect cup of coffee.
Functional Requirements: Your Coffee Maker's Features#
Functional requirements outline exactly what tasks the coffee maker must perform to deliver on user expectations. Think of these as the baseline features:
Brew coffee upon command: You press a button, and coffee reliably appears.
Select coffee type: Espresso, drip coffee, cappuccino — options tailored precisely to user preference.
Adjust brew strength: Whether you like your coffee mild or robust, the machine adjusts to meet your tastes.
Dispense hot water or steam: Beyond just coffee, it meets broader needs like making tea or steaming milk.
These functional elements directly shape user interactions, defining the core capabilities that must exist for the coffee maker to fulfill its primary purpose.
Nonfunctional Requirements: #
Nonfunctional requirements, on the other hand, detail how effectively the coffee maker executes its functions. These requirements shape the overall quality and long-term satisfaction with the product. Key examples include:
Performance (Quick brewing time): No one wants to wait too long for their coffee. The speed at which the machine brews coffee greatly influences user satisfaction.
Reliability (Consistent temperature): The machine must reliably deliver coffee at the optimal temperature, ensuring the quality of each cup is consistent.
Maintainability (Easy maintenance and cleaning): Regular, hassle-free upkeep keeps the machine in good shape and prevents disruptions.
User experience (Quiet operation): An overly loud machine could disrupt the environment, making quiet operation essential, especially in shared spaces.
Scalability and resilience (Energy efficiency and durability): Efficient energy usage and robust durability ensure the coffee machine continues performing well over time, even under heavy use.
These nonfunctional attributes don't define what the coffee maker does, but significantly influence how satisfying and usable it is, impacting user loyalty and brand reputation.
Who's thirsty?
IV. Types of System Design#
So you've got a grip on core components and essential considerations — now let's chat about the different types of System Design.
As someone who's spent years building and scaling systems at MAANG companies, truly mastering this discipline means understanding the different perspectives — and the different types — needed to build something robust, reliable, and lasting. You can break these down into two different categories:
Architectural styles: The fundamental blueprints that define how components are structured and interact, such as monolithic, microservices, and event-driven architectures.
Domain-specific System Design: This covers design approaches tailored to the unique requirements of specific domains, such as frontend System Design, generative AI System Design, etc.
1. Architectural styles#
Architectural styles are the core blueprint that dictates the entire structure, component interaction, and ultimately, your system’s scalability, maintainability, and performance. Get this right, and you lay a solid foundation; get it wrong, and you're building on quicksand.
Primarily, the architecture styles consist of:
Monolithic architecture: Many applications begin here, in a single, unified unit where all components are tightly coupled and run within one process. A monolith can be incredibly efficient initially for startups or projects with a very clear, limited scope. It allows for rapid development and straightforward deployment (here is great resource for a more in-depth look at modern deployment strategies)