System design interviews are crucial for assessing a candidate's ability to architect scalable, robust, and efficient systems. Having a solid grasp of key system design concepts can significantly boost your interview performance. Below are 50 essential terminologies that every aspiring system designer should know, with examples and learning resources.

Scalability

• Definition: The capacity of a system to handle growth by adding resources.
• Example: Adding more servers to manage increased web traffic.
• Learn More: What is Scalability and How to Achieve it?

Load Balancer

• Definition: A mechanism that distributes incoming network traffic across multiple servers to prevent overload on a single server.
• Example: Using AWS Elastic Load Balancer (ELB) to distribute web traffic among EC2 instances.
• Learn More: Understanding Load Balancer

Microservices

• Definition: An architectural style that structures an application as a collection of loosely coupled services.
• Example: Decomposing a monolithic application into independent services for user management, payment processing, and notifications.
• Learn More: What are Microservices?

CAP Theorem

• Definition: In a distributed system, only two out of the three guarantees—Consistency, Availability, and Partition Tolerance—can be fully achieved at the same time.
• Example: Choosing between consistency and availability in a distributed database design.
• Learn More: Understanding CAP Theorem

Sharding

• Definition: The process of dividing a large database into smaller, more manageable pieces called shards.
• Example: Sharding a user database by geographic region.
• Learn More: Database Sharding Explained

Latency

• Definition: The time it takes for data to travel from point A to point B.
• Example: Measuring the delay in message delivery in a chat application.
• Learn More: Latency Explained!

Throughput

• Definition: The amount of data a system processes in a specified timeframe.
• Example: The number of requests processed by a web server in one second.
• Learn More: Throughput in Computer Networks

Cache

• Definition: A hardware or software component that stores data to quickly serve future requests for the same data.
• Example: Using Redis to cache frequently accessed database queries.
• Learn More: Caching Explained

Content Delivery Network (CDN)

• Definition: A distributed network of servers that delivers web content based on a user's geographic location.
• Example: Implementing Cloudflare CDN to speed up web page loading.
• Learn More: What is a CDN?

REST API

• Definition: An architectural style for building web services where data is accessed and manipulated using HTTP requests.
• Example: Designing a Social Media API based on REST principles.
• Learn More: REST API Tutorial

GraphQL

• Definition: A query language for APIs that provides a more efficient and flexible alternative to REST.
• Example: Using GraphQL to fetch user information in a single query.
• Learn More: GraphQL Introduction

ACID

• Definition: A set of properties (Atomicity, Consistency, Isolation, Durability) ensuring reliable processing of database transactions.
• Example: Using ACID properties to ensure the integrity of a banking transaction.

• Learn More: ACID Properties in Databases

  BASE

• Definition: An alternative to ACID focusing on Availability and Partition tolerance, emphasizing a Basically Available, Soft state, Eventually consistent system.

• Example: Designing a highly available, eventually consistent NoSQL database.

• Learn More: BASE vs ACID

NoSQL

• Definition: A database type that enables the storage and retrieval of data in formats other than the traditional tabular format of relational databases.
• Example: Using MongoDB for a document-oriented data store.

• Learn More: What is a NoSQL Database?

  SQL

• Definition: The standard language used to manage and manipulate relational databases.

• Example: Writing SQL queries to retrieve data from a relational database.

• Learn More: SQL Tutorial

  Database Indexing

• Definition: A data structure technique that allows for fast searching and access to data within a database.

• Example: Creating an index on the User ID column to speed up search queries.

• Learn More: Database Indexing

Replication

• Definition: The process of copying and maintaining database objects across multiple databases in a distributed system.
• Example: Allowing a database to be highly available by replicating it across different geographic locations.
• Learn More: Database Replication

Failover

• Definition: A backup operational mode where functions are taken over by other components if a primary component fails.
• Example: Automatically switching to standby servers when a primary server fails.
• Learn More: Failover vs Disaster Recovery

API Gateway

• Definition: A server that acts as a single entry point for API requests, managing security, throttling, and routing to backend services.
• Example: Using AWS API Gateway to handle API requests.
• Learn More: What is an API Gateway?

Service Mesh

• Definition: An infrastructure layer that facilitates service-to-service communication in microservices architectures.
• Example: Integrating Istio to manage interactions between microservices.
• Learn More: Introduction to Service Mesh

Serverless Computing

• Definition: A cloud computing model that allows users to execute code without managing the underlying infrastructure.
• Example: Running backend code on AWS Lambda without provisioning servers.
• Learn More: What is Serverless Computing?

Event-Driven Architecture

• Definition: A software architecture pattern that promotes the generation, detection, consumption, and reaction to events.
• Example: Implementing a system where microservices communicate through events using Apache Kafka.
• Learn More: Event-Driven Architecture

Monolithic Architecture

• Definition: A traditional software architecture where all components are combined into a single application.
• Example: Legacy enterprise applications built as one large unit.
• Learn More: Monolithic vs Microservices Architecture

Distributed Systems

• Definition: A model where components on networked computers communicate and coordinate their actions by passing messages.
• Example: Designing a distributed file system like Hadoop.
• Learn More: Introduction to Distributed Systems

Message Queue

• Definition: A mechanism that enables asynchronous communication between services in microservices architectures.
• Example: Using RabbitMQ to manage messages between services.

• Learn More: Message Queues Explained

  Pub/Sub Model

• Definition: A messaging pattern where publishers send messages without needing to know the subscribers, allowing flexible communication.

• Example: A notification system utilizing Google Cloud Pub/Sub.

• Learn More: Pub/Sub Messaging

Data Partitioning

• Definition: The division of a database into smaller, manageable parts for efficiency.
• Example: Partitioning a database table by date to optimize query performance.
• Learn More: Database Partitioning

Horizontal Scaling

• Definition: Increasing system capacity by adding more machines or nodes.
• Example: Adding additional web servers to handle higher user traffic.

• Learn More: Horizontal vs Vertical Scaling

  Vertical Scaling

• Definition: Upgrading an existing machine by adding more powerful hardware.

• Example: Increasing the RAM of a server to manage more requests simultaneously.

• Learn More: Horizontal vs Vertical Scaling

Rate Limiting

• Definition: Controlling the traffic flow to a network interface to prevent overload.
• Example: Throttling an API to allow a maximum of 100 requests per minute.
• Learn More: Understanding Rate Limiting

Circuit Breaker Pattern

• Definition: A design pattern that detects failures and prevents a failure from recurring by stopping requests to failing services.
• Example: Using a circuit breaker to manage failed remote service calls in a microservices environment.
• Learn More: Circuit Breaker Pattern

Data Consistency

• Definition: The principle of ensuring that data remains accurate and reliable across multiple systems.
• Example: Ensuring all copies of a user record are the same across a distributed database.
• Learn More: Data Consistency Explained

Data Warehousing

• Definition: The process of collecting and managing data from various sources to provide meaningful business insights.
• Example: Using Snowflake for a centralized repository of historical data.
• Learn More: What is a Data Warehouse?

ETL (Extract, Transform, Load)

• Definition: The process of moving data from various sources, transforming it into a usable format, and loading it into a data warehouse.
• Example: Extracting sales data, transforming it for reporting, and loading it into a data warehouse for analysis.
• Learn More: [ETL Process Explained](https://aws.amazon.com/what-is/etl/#:~:text=Extract%2C%20transform%2C%20and%20load%20(,and%20machine%20learning%20)

Big Data

• Definition: Large volumes of data that cannot be processed effectively with traditional data processing applications.
• Example: Analyzing user data from social media platforms for trends.
• Learn More: What is Big Data?

Artificial Intelligence (AI)

• Definition: The simulation of human intelligence processes by machines, especially computer systems.
• Example: Implementing chatbots for customer support.

Machine Learning (ML)

• Definition: A subset of AI that uses statistical techniques to give computer systems the ability to "learn" from data.
• Example: Using ML algorithms to predict user behavior based on past interactions.

Data Lake

• Definition: A storage repository that holds vast amounts of raw data in its native format until it is needed.
• Example: Storing unprocessed log files for future analysis.
• Learn More: What is a Data Lake?

Blockchain

• Definition: A decentralized digital ledger used to record transactions across many computers securely.
• Example: Implementing a cryptocurrency system using blockchain technology.
• Learn More: Blockchain Basics

Observability

• Definition: The ability to measure the internal state of a system by examining its outputs.
• Example: Using tools like Grafana to monitor and visualize system metrics.
• Learn More: Understanding Observability

Monitoring

• Definition: The continuous observation of a system to ensure it operates correctly and efficiently.
• Example: Setting up alerts for server downtime using monitoring tools like Prometheus.
• Learn More: Monitoring in DevOps

Logging

• Definition: The practice of recording events that happen within a system for troubleshooting and analysis.
• Example: Using ELK stack (Elasticsearch, Logstash, Kibana) for centralised logging.
• Learn More: Logging Best Practices

Security Protocols

• Definition: A set of rules that ensure the secure transmission of data over networks.
• Example: Using HTTPS to secure web communications.
• Learn More: Understanding Security Protocols

Authentication

• Definition: The process of verifying the identity of a user or system.
• Example: Implementing OAuth2 for secure user authentication.
• Learn More: What is Authentication?

Authorisation

• Definition: The process of granting a user permission to access specific resources or functions.
• Example: Role-based access control (RBAC) for user permissions in a web application.
• Learn More: Understanding Authorisation

DevOps

• Definition: A set of practices that combines software development (Dev) and IT operations (Ops) to shorten the development lifecycle.
• Example: Implementing CI/CD pipelines for automated deployment.
• Learn More: What is DevOps?

Continuous Integration/Continuous Deployment (CI/CD)

• Definition: The practice of automatically testing and deploying code changes to ensure software quality and reliability.
• Example: Using Jenkins for automated testing and deployment of applications.
• Learn More: CI/CD Pipeline Explained

Agile Methodology

• Definition: A project management framework that emphasizes iterative development and collaboration.
• Example: Using Scrum to manage software development projects.

• Learn More: Agile Methodology Overview
  

  Load Testing

• Definition: The process of simulating real-world load on a system to ensure it can handle the expected traffic.

• Example: Using Apache JMeter to perform load testing on a web application.

• Learn More: Load Testing Best Practices

Latency vs. Jitter

• Definition: Latency is the time delay in data transmission, while jitter is the variation in packet arrival times.
• Example: Monitoring both metrics to ensure smooth video streaming experiences.
• Learn More: Understanding Latency and Jitter