Landing a job at Big Tech feels like a dream, but the path to get there is rarely simple. The toughest hurdle? System design concepts. These are the secret rules that drive Internet giants such as Netflix, Amazon, and Google. They determine if an application performs well in the hands of millions of users or collapses under stress.

A majority of candidates enter a system design interview and freeze. Not because they are poor engineers, but because they are not able to describe how the blocks of the building are going to fit. The positive thing is, when you get these principles straight, interviews no longer feel intimidating but rather an opportunity to flaunt your talents.

Recruiters in Big Tech do not desire memorized definitions. They would like to observe your ways of thinking, problem-solving, and designing under stress. This is why it is your cheat code, a convenient kit of 30 ideas outlined in simple, plain language. You will not only be interview-ready by the end, but you will also be thinking like the engineers who create the apps you use daily.

30 Core System Design Concepts to Crack Big Tech Jobs

1. Client-Server Architecture

The client makes a request to the server in this model, which processes it and responds. It is the one that drives nearly all online services, social media, and commerce. It enables apps to support thousands of users simultaneously. In the absence of this model, there would be no ability to communicate and apply globally. It is the most significant point at the beginning of learning systems design concepts. Scalable architecture is utilized by businesses to build stable apps.

2. IP Address

An IP address is a computer number on the Internet. All the devices that are linked to a network utilise this number to transmit and retrieve information appropriately. The first one was IPv4, and now IPv6 is used to serve billions of devices. The concept of IP addresses makes the connection of services throughout the globe advantageous. In their absence, no online communication would occur. It is critical to know this clearly during a system design interview.

3. Domain Name System (DNS)

DNS converts human-readable names such as google.com into IP addresses that are readable by machines. It simplifies the Internet for users and conceals technical complexity. Distributed DNS systems are operated by large companies to enhance reliability and prevent failures. Even the biggest services, such as Amazon, can be out of reach in the case of DNS failure. To avoid downtime, engineers need to develop a DNS backup. This is a core part of system design fundamentals.

4. Proxy and Reverse Proxy

A proxy will link a user to the Internet without revealing the actual identity. A reverse proxy serves to secure servers by blocking requests, load balancing, and caching. Reverse proxies are used by businesses such as Cloudflare to secure websites and enhance performance. Large systems would not be able to cope with heavy traffic without them. They are also used to prevent attacks before they hit servers. This is enumerated as one of the core concepts in system design.

5. Latency

Latency is the process through which the data moves between the server and the client. High latency causes apps to be slow, whereas low latency causes them to be responsive. Live video calls and online gaming require extremely short delays to be smooth. CDNs, caching, and enhanced routing help engineers to minimize latency. Latency management is critical in systems with millions of requests per second. One of the problems in Big Tech jobs is reducing delays.

6. HTTP and HTTPS

The HTTP protocol enables the browsers and the servers to communicate. A secure version is called HTTPS, which encrypts information, preventing hackers. Any online service that handles payments or personal information should go through HTTPS. It creates user confidence and eliminates data leakage across the internet. Web communication is based on these protocols. System design interview preparation requires knowing them well.

7. APIs

APIs are agreements that specify system interactions. They enable applications to leverage such features as maps, payments, or chat without developing them. This increases the speed and stability of development across industries. APIs standardize communication and minimize project complexity. All modern applications are based on APIs. This is why they are never left out of a system design guide.

8. REST API

REST APIs are rule-based and are based on HTTP. They are easy and adaptable to exchange data in forms such as JSON or XML. REST is lightweight and can be scaled in large systems. Users like it as it is compatible almost everywhere. REST APIs are used in many web platforms, such as Twitter and GitHub. It is often introduced as part of system design for beginners.

9. GraphQL

GraphQL is a powerful client request language. It enables one to request the desired amount, rather than over-fetching or under-fetching, which enhances performance and efficiency. GraphQL is also being discussed as a hot topic in modern system design, now that Facebook built it to make queries more specific and quicker than ever, and the same argument persists AI vs Human about the intersection of creativity and automation at the technological core.

10. Databases

Information is stored, organized and accessed in databases. SQL databases process structured data, and NoSQL processes flexible, unstructured data. The selection of the proper type is dependent on the problem to be solved. Instagram and other companies depend on databases to handle billions of records in a day. In their absence, no application could store user data. They are the backbone of system design fundamentals.

11. SQL vs NoSQL

SQL relies on fixed tables, while NoSQL supports flexible formats like documents or key-value pairs. In terms of reliability, SQL offers stronger consistency. By contrast, NoSQL stands out for its scalability and flexibility. In large systems, engineers frequently mix the two. This choice impacts performance and data integrity. Making the right decisions is part of creating scalable applications. It is a typical question during system design fundamentals.

12. Vertical Scaling

Vertical scaling involves upgrading one server with additional RAM, CPU, or storage. It is easy to apply and constrained by hardware. It is commonly the initial move in developing applications. But it is not able to sustain unlimited growth. Later, companies scale horizontally to accommodate more users. It is often introduced in system design fundamentals.

13. Horizontal Scaling

Horizontal scaling implies the addition of servers rather than a simple upgrade. This is how apps such as Netflix entertain millions of people across the globe. This approach enables systems to expand practically indefinitely. It needs sophisticated synchronization and data distribution tools. This model is used by engineers in large systems. It is a key skill for Big Tech jobs.

14. Load Balancers

Load balancers spread requests among servers so that no server fails. They enhance reliability and uptime for users. When one server fails, the load balancer diverts traffic to healthy servers. This keeps the apps stable even in cases of high traffic. HAProxy or AWS Load Balancer are tools used by many businesses. They are very important in system design interview preparation.

15. Database Indexing

Indexing is the provision of shortcuts in a database that accelerates queries. Searching a large dataset without indexes can take minutes. Queries are completed in seconds or fewer with them. They enhance user experience with apps that handle large volumes of data. In designing indexes, engineers have to compromise between speed and storage costs. A system design guide always covers them.

16. Replication

Replication provides backup of data on multiple servers to ensure availability and protection. When one server goes down, another one has the information. This eliminates downtime for users in case of failure. Replication also enhances performance when servers are nearer to users. It is a typical distributed system design in the world. This is why it continues to be a pillar of system design fundamentals.

17. Sharding

Sharding divides a big database into fragments known as shards. All the shards process a portion of the data, which enhances speed and pressure. Instagram is a global app utilizing sharding to scale to billions of users. It assists performance as the systems expand. Shard key design is highly essential. Sharding is frequently covered by system design interview questions.

18. Vertical Partitioning

Vertical partitioning splits a database based on columns rather than rows. It comes in handy when a field is used more frequently than others. This minimizes query time and consumption. It assists in creating learner databases. It also cuts expenses by placing data that is not frequently used in different stores. This method is part of core concepts in system design.

19. Caching

Caching stores often use memory to store frequently used information. It minimizes latency and accelerates apps significantly. Services such as YouTube and Facebook rely on caching to provide smooth experiences. Caches are located near users so that the results can be quick. They also decrease the workload in central servers. This is why caching is a significant instrument of Big Tech jobs.

20. Denormalization

Denormalization is the addition of redundant information in databases to minimize query times. The method eliminates costly joins and accelerates performance. Engineers apply it when reporting systems need speed more than storage efficiency. However, they must handle it with caution to avoid data errors. Ultimately, it represents a compromise between pace and precision. This is frequently in system design interview preparation.

21. CAP Theorem

The CAP theorem states that distributed systems can only assure two out of three, i.e. consistency, availability, and partition tolerance. Depending on the system, engineers have to make decisions on what to sacrifice. Consistency in banking apps and availability on social media can be examples. This property informs a lot of design choices at scale. All architects should know it well. Any system design guide features it.

22. Blob Storage

Blob storage is built to hold unstructured information such as images, videos and audio. Examples of cloud storage providers include AWS and Azure. It is economical and manages big volumes of media. Such applications as Spotify use it to store music files. It is easily scalable as the data increases. This is why it is a significant aspect of modern system design.

23. Content Delivery Network (CDN)

A CDN stores copies of data in various geographic locations. Users receive information on the closest server, which minimizes latency. Apps that have global audiences, such as Netflix or YouTube, are essential. CDNs also lessen server loads by caching static files. In the absence of CDNs, distant users of the main server would experience elevated latency. This is what makes them still belong to system design fundamentals.

24. WebSockets

WebSockets enable real-time bi-directional communication between the server and client. They are applied in online games, trading platforms, and chat applications. They maintain an open connection, unlike HTTP. This enhances live update performance. WebSockets are essential when milliseconds count. System design interview preparation usually involves them.

25. Webhooks

Webhooks allow one system to give instant updates to another. As an example, a payment gateway can notify your app when a payment is processed. They eliminate the necessity to check regularly and save resources. Most SaaS platforms today use webhooks. They render systems interactive and responsive. Webhooks are an easy yet effective instrument in core system design concepts.

26. Microservices

Microservices divide a big application into tiny services. Every service deals with a single job, e.g. payments or search. This simplifies systems to construct, maintain, and grow. It also minimizes the possibility of complete inactivity in case a single component fails. Amazon, Netflix, and Uber scale on microservices. That is why they are typical of Big Tech jobs, and the significance of scalability is also brought up in Why 10% of Startups Succeed While 90% Fail.

27. Message Queues

Message queues enable services to communicate without waiting for one another. They save requests until the system is available to handle the requests. This will avoid overloading when there is a surge in traffic. Common ones, such as RabbitMQ and Kafka, have become popular. They are essential to the dependability of distributed systems. They are common subjects of system design interview preparation by engineers.

28. Rate Limiting

Rate limiting regulates the number of requests a user can make within a particular period. It prevents abuse and keeps servers running smoothly. Platforms such as Twitter rely on it to block spam and protect resources. This approach also ensures fair usage for all customers. The tokens and fixed windows are used to rate limit. This makes it part of system design fundamentals.

29. API Gateways

Multiple microservices share one entry point, which is an API gateway. It manages routing, security and monitoring of API traffic. This eases the interaction with clients through obscurity. It also enhances performance and control in large systems. Popular tools such as Kong and AWS API Gateway are popular. This is why they are basic in any system design guide.

30. Idempotency

Idempotency implies that the same request has the same result. As a case in point, two Pay presses are not supposed to cost twice. It enhances trust in distributed systems. This principle is always applied in payment systems and booking apps. It secures users and confidence in apps. Idempotency is a normal question in system design interview questions.

Conclusion

The quickest method to equip yourself to interview and face the world is learning these 30 concepts. They demonstrate how systems grow, remain dependable, and handle billions of users per day. These system design concepts will provide you with the confidence to approach the solution of any design problem. These skills will enable you to think bigger and create your career in Big Tech.