Motivation
Learn how to design large-scale systems and prep for the system design interview.
Learn how to design large-scale systems
Learning how to design scalable systems will help you become a better engineer. System design is a broad topic. There is a vast amount of resources scattered throughout the web on system design principles. This repo is an organized collection of resources to help you learn how to build systems at scale.Learn from the open source community
This is a continually updated, open source project. Contributions are welcome!Prep for the system design interview
In addition to coding interviews, system design is a required component of the technical interview process at many tech companies. Practice common system design interview questions and compare your results with sample solutions: discussions, code, and diagrams.Study guide
Suggested topics to review based on your interview timeline
Anki flashcards
Spaced repetition flashcard decks for key concepts
How to approach a system design interview question
You can use the following steps to guide the discussion. To help solidify this process, work through the system design interview questions 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
Back-of-the-envelope calculations
You might be asked to do some estimates by hand. Refer to the Appendix for the following resources:- Use back of the envelope calculations
- Powers of two table
- Latency numbers every programmer should know