Designing a system that support millions of users is challenging, and it is journey that requires continuous refinement and endless improvement. In this blog, we build a system that supports a single user and gradually scale it up to serve millions of user.

Scale from zero to millions of users

JavaScript is a single-threaded programming language, so it can't run multiple things at the same time, Promise.all() actually runs promises concurrently, not in parallel!. Let's dive in to see how it works.

Does JavaScript Promise.all() run in parallel or sequential?

Conventional commit is a specific form of committing which gives software developers a uniform system for organizing and describing their changes, making it easier to keep track of updates

Introduction to Committing with Conventional Commit

Key notes to save plenty of time while working with git for command-line-developer

Key notes while working with git

If you are familiar with functional programming, Array.prototype.map must be a function that you work with every day. We encountered a tricky use case of it at Cốc Cốc recently, it took me a while to figure out, and here's the answer...

Tricky use case of Array.prototype.map in JS

Learn about the differences between Function Declaration and Function Expression in JavaScript, including their definitions, hoisting behavior, and when to use each method.

When to use Function Declaration vs Function Expression in JavaScript?

Module Federation in Webpack 5

Micro Frontend - A Practical Guide to Designing Scalable Systems

The blog provides a comprehensive guide on how to set up a personalized version of ChatGPT, tailored to specific datasets. It covers two primary aspects: the ingestion of targeted data and the creation of a chatbot interface that utilizes this data. The post is designed to be a step-by-step tutorial, complete with code references from an accompanying GitHub repository. While focusing mainly on text data, it also offers directions for integrating ChatGPT with other types of data sources, such as SQL databases and APIs, aiming to enhance the utility and customization of the ChatGPT model for individual users or specific applications.

Crafting Your Own AI: A Journey into Personalized ChatGPT Integration

This blog explores the potential of ChatGPT-4 and Large Language Models in software development,  focusing on prompt engineering, practical applications, and integrating GPT-4 Turbo with Python for innovative solutions.

ChatGPT-4 prompt engineering for developers

This is a collection of prompt examples to be used with the ChatGPT model.

The awesome ChatGPT promts

Designing good systems requires years of accumulation of knowledge. One shortcut is to dive into real-world system architectures. Below is a collection of helpful reading materials. We highly recommend you pay attention to both the shared principles and the underlying technologies. Researching each technology and understanding what problems it solves is a great way to strengthen your knowledge base and refine the design process.

The learning continues

In recent years, cloud storage services such as Google Drive, Dropbox, Microsoft OneDrive, and Apple iCloud have become very popular. In this chapter, you are asked to design Google Drive.

Design google drive

In this blog, you are asked to design YouTube. The solution to this question can be applied to other interview questions like designing a video sharing platform such as Netflix and Hulu.

Design youtube

When searching on Google or shopping at Amazon, as you type in the search box, one or more matches for the search term are presented to you. This feature is referred to as autocomplete, typeahead, search-as-you-type, or incremental search. Figure 13-1 presents an example of a Google search showing a list of autocompleted results when “dinner” is typed into the search box. Search autocomplete is an important feature of many products. This leads us to the interview question: design a search autocomplete system, also called “design top k” or “design top k most searched queries”.

Design a search autocomplete system

In this blog, you are asked to design a news feed system. What is news feed? According to the Facebook help page, “News feed is the constantly updating list of stories in the middle of your home page. News Feed includes status updates, photos, videos, links, app activity, and likes from people, pages, and groups that you follow on Facebook” [1]. This is a popular interview question. Similar questions commonly asked are: design Facebook news feed, Instagram feed, Twitter timeline, etc.

Design a chat system

Design a new feed system

A notification system has already become a very popular feature for many applications in recent years. A notification alerts a user with important information like breaking news, product updates, events, offerings, etc. It has become an indispensable part of our daily life. In this chapter, you are asked to design a notification system.

Design a notification system

In this chapter, we focus on web crawler design: an interesting and classic system design interview question.

Design a web crawler

In this blog, we will tackle an interesting and classic system design interview question: designing a URL shortening service like tinyurl.

Design a URL shortener

In this chapter, you are asked to design a unique ID generator in distributed systems. Your first thought might be to use a primary key with the auto_increment attribute in a traditional database. However, auto_increment does not work in a distributed environment because a single database server is not large enough and generating unique IDs across multiple databases with minimal delay is challenging.

Design a unique id generator in distributed systems

A key-value store, also referred to as a key-value database, is a non-relational database. Each unique identifier is stored as a key with its associated value. This data pairing is known as a “key-value” pair.

Design a key-value store

To achieve horizontal scaling, it is important to distribute requests/data efficiently and evenly across servers. Consistent hashing is a commonly used technique to achieve this goal. But first, let us take an in-depth look at the problem.

Design consistent hashing

 In a network system, a rate limiter is used to control the rate of traffic sent by a client or a service. In the HTTP world, a rate limiter limits the number of client requests allowed to be sent over a specified period. If the API request count exceeds the threshold defined by the rate limiter, all the excess calls are blocked.

Design a rate limiter

You have just landed a coveted on-site interview at your dream company.  The hiring coordinator sends you a schedule for that day. Scanning down the list,  you feel pretty good about it until your eyes land on this interview session - System Design Interview.

A framework for system design interviews

In a system design, sometimes you are asked to estimate system capacity or performance requirements using a back-of-the envelope estimation. According to Jeff Dean, Google Senior Fellow, "back-of-the-envelope calculations are estimates you create using a combonation of thought experiments and common performance  numbers to get a good feel for which designs will meet your requirements".