The system design interview is an open-ended conversation. You are expected to lead it.
You can use the following steps to guide the discussion. To help solidify this process, work through the System design interview questions with the solutions section using the following steps.
Step 1: Outline use cases, constraints, and assumptions Gather requirements and scope the problem. Ask questions to clarify use cases and constraints. Discuss assumptions.
Who is going to use it? How are they going to use it? How many users are there? What does the system do? What are the inputs and outputs of the system? How much data do we expect to handle? How many requests per second do we expect? What is the expected read to write ratio? Step 2: Create a high-level design Outline a high-level design with all important components.
Sketch the main components and connections Justify your ideas Step 3: Design core components Dive into details for each core component. For example, if you were asked to design a URL shortening service, discuss:
Generating and storing a hash of the full URL MD5 and Base62 Hash collisions SQL or NoSQL Database schema Translating a hashed URL to the full URL Database lookup API and object-oriented design Step 4: Scale the design Identify and address bottlenecks, given the constraints. For example, do you need the following to address scalability issues?
Load balancer Horizontal scaling Caching Database sharding Discuss potential solutions and trade-offs. Everything is a trade-off. Address bottlenecks using principles of scalable system design.
