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Book: Browser Extension Book

  1. Introduction
  2. Understanding browser extensions. Setting up your development environment.
  3. Setting up a Node.js server with TypeScript, Express.js.
  4. User Authentication.
  5. Implementing stripe subscriptions.
  6. Adding LLM Feature and Deployment.


We keep our book up to date with recent libraries and packages.

Welcome to the exciting world of browser extension development! This book is designed to guide you through the process of creating your own browser extensions, using technologies you might already be familiar with like JavaScript, React, and Express. Whether you're looking to enhance your browsing experience, improve productivity, or even build something entirely new, this journey will equip you with the skills needed to bring your ideas to life.

Who This Book Is For link

This guide is tailored for junior developers or anyone with a basic understanding of web technologies who wants to step into the world of browser extensions. We assume you have a fundamental grasp of JavaScript, as well as some familiarity with React, and Express. However, when it comes to extension-specific concepts, we'll dive into detailed explanations and step-by-step instructions to ensure you can follow along, regardless of your prior experience with browser extensions.

What You Will Learn link

By the end of this book, you will have learned:

  • The basics of browser extensions and how they work.
  • How to set up your development environment for building extensions.
  • How to create interactive and dynamic extensions using JavaScript and React.
  • How to handle background processes and communications in extensions using Express.
  • Best practices for debugging and testing your extensions.
  • How to publish your extensions to browsers like Chrome and Firefox.

Structure of the Book link

The book is structured into five comprehensive chapters:

  1. Browser extension basics, Development setup
  2. Setting up a Node.js server with TypeScript, Express.js, and Yarn
  3. User Authentication
  4. Implementing stripe subscriptions
  5. Adding LLM Feature and Deployment

Each chapter is crafted to build upon the knowledge gained in the previous ones, progressively enhancing your skills and understanding of browser extension development.

Project structure link

Take a look at the final code and the codebase for each chapter.

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Stripe subscription section in options page link

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Authors link


  • maintain two popular repos (combined: over 6000 stars and 1000 unique visitors per week).
  • built and maintain the most popular React/TypeScript/Node boilerplate for starting a SaaS business.
  • built Async, open source team communication web app to separate urgent vs non-urgent conversations.
  • built Work in biotech, growing niche job board for biotech startups.
  • built AI-cruiter, browser extension is built for recruiters managing a high volume of job applicants. AI-cruiter uses LLMs - like ChatGPT, PaLM 2, our private fine-tuned LLM - to generate succinct and relevant summaries of your job applicants' resumes.
  • built over a dozen SaaS web applications in the last 10 years and offer custom development service:

Learn more about us at Async Labs.

You can find us on GitHub:

If you are part of a small team and looking for an open source team communication tool, check up Async.

We keep our book up to date with recent libraries and packages.