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How To Build Your First Chrome Extension

Last edited 4 minutes ago by Adam Martelletti
We've all been there - you're on your browser, looking for that perfect add-on to spice up your experience, but none of the existing extensions quite fit the bill. Wouldn't it be easier if you could just create your own Chrome extension?
Sure, it sounds like a lot of work, but I'm here to tell you that creating a Chrome extension is actually much simpler than you'd initially think.

Disclaimer
This guide is not intended to be a definitive source of information on building a Chrome Extension but rather a reflection of my own personal learning process.
The information has been collected from multiple sources, including outputs from A.I. and fact-checked to the best of my ability and should be viewed as my personal notes on the topic that have been shared publicly.

The recommended option for a React Chrome Extension will depend on your specific requirements and the resources you have available.

However, using AWS Lambda and API Gateway together is a common and cost-effective way to build and run the backend of a Chrome Extension.
React
Node.js
AWS Lambda
Firebase

Planning
Before starting to build your extension, it's important to have a clear understanding of the requirements and goals of your project. This includes identifying the main features of your extension, the user flow, and the data that needs to be stored and retrieved. Also, you should consider the performance, scalability, and security of your extension. Additionally, you need to have a clear idea of the architecture and the technologies that will be used to build the extension.
This is a basic example, steps and tasks for building a chrome extension you might need to adjust it depending on your specific requirements and needs.
Define the scope of the chrome extension:
Identify the main features of the extension
Define the target audience
Define the functional and non-functional requirements
Define the success metrics
Design the architecture:
Identify the technologies that will be used
Design the data flow between the extension and the backend
Design the data flow between the extension and the databases
Design the data flow between the extension and the APIs
Build the chrome extension:
Create the basic structure of the extension using React
Implement the web scraping feature using JavaScript
Implement the API calls to the Lambda function using Node.js
Implement the security and privacy measures
Implement the data storage and retrieval feature using Firebase or other NoSQL databases
Test and debug the chrome extension:
Once the extension is built, it's important to test it thoroughly to make sure that it's working as expected. This includes testing the user flow, the data retrieval and storage, and the communication with external services.
Test the extension on different browsers
Test the extension on different operating systems
Test the extension with different data sets
Test the extension with different user scenarios
Debug and troubleshoot any issues
Deploy and publish the chrome extension:
After testing, you'll need to deploy the extension to the Chrome Web Store, so it can be installed by users.
Package the extension for deployment
Publish the extension on the Chrome webstore
Test the extension after publishing
Monitor the extension after publishing
Maintenance
After the extension is deployed, it's important to keep it up-to-date and maintain it. This includes fixing bugs, updating dependencies, and adding new features. It's also important to monitor the performance and usage of the extension, and make adjustments as necessary.
Monitor the extension usage
Monitor the extension performance
Handle user feedback and bug reports
Handle updates and versioning

Framework
There are several JavaScript frameworks that can be used to build a Chrome extension, each with their own set of advantages and disadvantages.
React and Angular are popular choices for building complex and feature-rich web applications, and they can also be used to build a Chrome extension. They provide a robust set of tools and features that can help you manage the state of your extension and make it easier to work with external APIs and databases.
Vue.js is a lightweight framework that is well suited for building small to medium-sized applications. It is easy to learn and has a simple and intuitive syntax.
jQuery is a popular JavaScript library that can be used to easily manipulate the DOM and make HTTP requests. It is a good choice if you are building a simple extension and don't need the additional features provided by a full-featured framework.
It really depends on your experience and familiarity with the framework, as well as the complexity of your extension. I would recommend using React or Angular if you are building a complex extension that will interact with multiple external APIs and databases. If you are building a simple extension, Vue.js or jQuery would be a good choice.
Keep in mind that, regardless of the framework you choose, you will need to have a good understanding of the Chrome Extension API and JavaScript in general to build a functional extension.
React vs Angular
React and Angular are both popular JavaScript frameworks that can be used to build complex web applications and Chrome extensions. Both frameworks are widely used in the industry and have a large and active community of developers.
React is a JavaScript library for building user interfaces. It is maintained by Facebook and has a small footprint and can be easily integrated into other projects. React uses a virtual DOM, which allows for efficient updates and rendering of components. It also has a large ecosystem of third-party libraries, such as React Router for client-side routing and Redux for state management.
Angular, on the other hand, is a full-featured framework for building web applications. It is maintained by Google and provides a complete set of tools and features, including a powerful template engine, a dependency injection system, and a built-in CLI tool for generating and scaffolding new projects. Angular uses a real DOM, which allows for a more natural and intuitive way of working with the DOM.
Both React and Angular are suitable choices for building a Chrome extension. However, depending on your experience and familiarity with the framework, as well as the complexity of your extension, one may be more appropriate than the other.
If you are more familiar with React, it may be easier for you to use that to build your extension. If you are more familiar with Angular, it may be a better choice.
If you are new to both of the frameworks, I would recommend learning React first as it will have a shallower learning curve and it's easier to pick up.
In any case, both frameworks are powerful and can be used to build a high-quality Chrome extension, just make sure to take into account the complexity of your project and the resources you have available to complete it.
Other Languages

JavaScript
JavaScript is a versatile programming language that is commonly used for building web applications and browser extensions. React, which is the front-end library that you'll be using, is also written in JavaScript, so it makes sense to use JavaScript for the front-end of your extension.
Node.js
Node.js, on the other hand, is a JavaScript runtime that allows you to run JavaScript code on the server side, so you can use Node.js to build the backend of your extension. Node.js is widely used for building backends for web applications and browser extensions because it's lightweight, fast, and has a large ecosystem of modules and libraries.
JavaScript and Node.js are a perfect match for building web and browser-based applications, and they are widely adopted in the industry, so you'll find many developers with experience in these technologies.
You can also use other languages like Python, Ruby, or Go, but it is important to keep in mind that JavaScript and Node.js are the most common and recommended languages for building web and browser-based applications.
It is also important to note that the database you choose might have a specific language to connect and query, so make sure to check that the developers you hire are proficient in that language as well.
Run code
There are a few different options for running code in the backend for a chrome extension. One popular option is to use a serverless platform like AWS Lambda, which allows you to run code without provisioning or managing servers.
Another option is to use a container orchestration platform like Kubernetes or Docker, which allows you to run your code in containers and manage the scaling and deployment of your application.
Here's a high-level overview of the steps you would take to run code in the backend for a chrome extension:
Write the code for your backend application in a language that is supported by your chosen platform (e.g. Node.js for Lambda or any language with a runtime image available in Docker hub)
Package your code and any dependencies into a deployable format (e.g. a zip file for Lambda or a container image for Kubernetes)
Deploy your code to your chosen platform. For example, you can use the AWS Lambda console to create a new function and upload your code, or use a tool like kubectl to deploy your containerized application to a Kubernetes cluster.
Update the chrome extension to call the API of the backend code.
Once your code is deployed, you can test it by making requests to the API endpoint provided by your platform (e.g. the API Gateway URL for Lambda or the service endpoint for Kubernetes)
Once you have tested the code and confirmed that it is working as expected, you can release it to your users by publishing the chrome extension on the chrome web store.
Continuously monitor the backend code and update it as needed.
It is important to note that running code in the backend for a chrome extension also requires security and scalability considerations. It is recommended to use a VPC, configure security groups, use https and authentication methods to secure the API calls and protect the data.
AWS Lambda
Lambda provides a secure and isolated environment to run your code in response to events, such as an API request, without having to provision or manage servers. You can use Lambda to execute your backend code, such as scraping the webpage and checking the external database, and handle the heavy lifting of securely connecting to your backend services.
Lambda VS Firebase Cloud Functions AWS Lambda and Firebase Cloud Functions are both serverless compute services that allow you to run your code without provisioning or managing servers.
Lambda is a service provided by Amazon Web Services (AWS) that allows you to run your code without provisioning or managing servers. It supports a wide range of programming languages, including JavaScript, Python, and C#.
Firebase Cloud Functions is a service provided by Google Firebase that allows you to run your code in response to specific events, such as changes to your Firebase Realtime Database or Firestore. Cloud Functions supports JavaScript and TypeScript.
Both services allow you to run your code in response to specific events and scale automatically, but Lambda has more support for programming languages and has more advanced features for monitoring and debugging. On the other hand, Cloud Functions is tightly integrated with other Firebase services, and it's easier to set up and use for Firebase specific use cases.
It will depend on your use case and existing infrastructure which one will be the best fit for you.
If you are already using Firebase and want to add serverless functionality, Cloud Functions would be the more natural choice.
If you want more flexibility and control over your serverless infrastructure, Lambda might be the better option.
API Gateway
An API Gateway is a service that sits in front of your backend services and APIs, acting as a reverse proxy and routing incoming requests to the appropriate service or resource. An API Gateway can help you to handle common concerns such as security, rate limiting, caching, and logging in a centralized way.
When you use an API Gateway to handle requests for your chrome extension, you can use it to authenticate and authorize requests, perform input validation, and transform incoming requests and outgoing responses.
With an API Gateway, you can also define different routes, methods and endpoints to access different functionalities of your backend. For example, you can use the API Gateway to expose different endpoints for different functionalities such as creating an account, login, searching databases and so on.
AWS has a service called Amazon API Gateway, which is a fully managed service that makes it easy to create, publish, maintain, monitor, and secure APIs at any scale. You can use Amazon API Gateway to create an API that acts as a “front door” for applications to access data, business logic, or functionality from your backend services, such as AWS Lambda, AWS AppSync, or an HTTP endpoint.
Other cloud providers such as Azure and GCP also have their own API Gateway Services.
Overall, an API Gateway can help you to build a more robust and scalable architecture for your chrome extension, by separating the concerns of the client and the backend, and allowing you to add new features and services more easily.

Using API Gateway, AWS Lambda, and Firebase together
You can use an API Gateway, AWS Lambda, and Firebase together to build your chrome extension. Below is a high-level overview of how they can work together:
The chrome extension sends a request to the API Gateway.
The API Gateway authenticates and authorizes the request, and routes it to the appropriate Lambda function.
The Lambda function, written in Node.js, performs the necessary logic and data processing, such as querying or updating data in the Firebase database.
The Lambda function returns the response to the API Gateway, which can transform or format the response before sending it back to the chrome extension.
The chrome extension receives the response and displays the information to the user.
By using this approach, you can separate the concerns of the frontend and the backend, and take advantage of the benefits of each service.
The chrome extension only needs to handle the UI and user interactions, while the Lambda function and Firebase handle the data processing and storage. The API Gateway acts as a gatekeeper, handling security, rate-limiting, and other common concerns.
It's worth mentioning that there are other databases options other than Firebase, like MongoDB, MySQL, and PostgreSQL that can be used as well, depending on your needs and preferences.
It's also worth noting that Firebase can also handle the authentication and authorization for your extension, so you don't have to implement that on your own.
Storage
Using an Amazon S3 bucket for storage is a good choice if you need to store large amounts of data, such as images or other files. S3 is an object storage service, which means it stores data as objects, rather than as files or blocks. Each object is stored in a bucket, which is a container for objects.
S3 offers a number of benefits for storing data, including:
Scalability: S3 can store and retrieve any amount of data, at any time, from anywhere on the web.
Data availability: S3 is designed for 99.999999999% (11 9's) of durability.
Security: S3 provides a number of security features, including encryption, access control, and monitoring.
Performance: S3 provides low-latency and high-throughput performance, and it can be used to store and retrieve data in a variety of formats, such as text, images, and video.
To use S3 for storage, you can create a new bucket and then upload your data to it using the S3 web console, the AWS SDK, or the AWS CLI. Once your data is stored in an S3 bucket, you can retrieve it at any time using the same tools.
Additionally, S3 also offers features such as versioning, lifecycle policies, and cross-region replication which can be useful in certain use cases.
In summary, S3 is a good choice for storing images or other files because it offers scalability, data availability, security, and performance.
Database
All these databases are great for a Chrome extension and can handle high-performance and high-concurrency workloads, but it depends on our specific requirements. Make sure you evaluate each option based on factors such as data model, scalability, performance, security, and pricing before making a decision.
Database options
MongoDB: MongoDB is a popular, document-oriented NoSQL database that is well-suited for storing semi-structured data. It is a good option if you need a database that can handle high write and read throughput, and it's easy to scale horizontally. MongoDB also has a rich query language and supports secondary indexes, making it easy to perform complex queries.
Firebase Realtime Database: Firebase Realtime Database is a cloud-based NoSQL database that stores data as JSON and can be accessed directly from client-side code. It's great for real-time applications, and it has built-in security and authentication features, It can also handle high read and write throughput and supports offline access to data.
Amazon DynamoDB: Amazon DynamoDB is a fully managed NoSQL database service that provides fast and predictable performance with seamless scalability. It's a good option if you need a highly available and scalable database, and it also has built-in security and compliance features.
Google Cloud Firestore: Cloud Firestore is a flexible, scalable NoSQL cloud database to store and sync data for client- and server-side development. It is a document-oriented database, and it has built-in security and compliance features.
SingleStore: SingleStore is a managed database service that provides a high-performance, globally distributed SQL database that can be used as a drop-in replacement for traditional relational databases like MySQL or PostgreSQL. SingleStore is designed to handle high-performance, high-concurrency workloads, and it can be used to power real-time analytics and OLAP workloads
MySQL: Is a popular, open-source relational database management system (RDBMS) that is known for its reliability, high performance, and ease of use. It is widely used in web applications and can be used to store structured data. MySQL also supports a variety of storage engines, including InnoDB and MyISAM, which can be used for different use cases.
PostgreSQL: On the other hand, is a powerful, open-source RDBMS that is known for its robustness, scalability, and support for advanced data types and indexes. It is widely used in web applications, data warehousing, and business intelligence systems. PostgreSQL supports a wide variety of data types and has a rich set of data manipulation and management features.
Both MySQL and PostgreSQL are good options for your React Chrome Extension project, but you'll need to evaluate each option based on your specific requirements. If you need a high-performance and scalable database that can handle a lot of concurrent write and read operations, NoSQL databases like MongoDB, Firebase, DynamoDB, Cloud Firestore, or SingleStore are a better option. If you need a database that supports advanced data types, indexes, and complex queries, PostgreSQL is a better option.
Database interaction
It is also important to keep in mind that the database choice also depends on the developers you hire and their proficiency in a specific database.
You can use Node.js to interact with databases like Firebase. Firebase provides a Node.js library that you can use in your Node.js code to interact with its various services, including the Realtime Database, Cloud Firestore, and Authentication.
The Firebase Node.js library provides a simple and powerful API that you can use to read, write, and query data from Firebase, as well as perform authentication and authorization tasks. The library supports real-time data synchronization, offline data access, and automatic data scaling.
You can use the Firebase Node.js library in your Node.js code to connect to the Firebase services and perform various database operations like creating, reading, updating and deleting records.
In addition to Firebase, you can also use other popular database solutions such as MongoDB, MySQL, PostgreSQL, etc. with Node.js using their specific libraries or drivers like Mongoose, Sequelize, etc.
It's worth noting that Firebase is a BaaS (Backend as a Service) solution that provides a lot of built-in features like authentication, storage, and hosting. It abstracts away the complexity of managing a backend and allows you to focus on building your application.
In summary, you can use Node.js to interact with Firebase and other databases, and it provides libraries and drivers that makes it easy to do so.
Security
It is important to ensure that the extension and the backend services are secure. This includes securing the communication between the frontend and the backend, encrypting the data that is stored, and implementing authentication and authorization mechanisms.
Best practices
Here are some steps you can take to ensure that your Chrome Extension has the correct permissions to access the external database and that you are following best practices for securing and protecting user data:
Use OAuth2 or OpenID Connect for authentication: Use OAuth2 or OpenID Connect to authenticate users and obtain access tokens that can be used to access the external database. This will ensure that only authorized users can access the database, and that their data is protected.
Use HTTPS for all network communication: Use HTTPS for all network communication between the Chrome Extension and the external database. This will ensure that all data transmitted between the extension and the database is encrypted and secure.
Use a Content Security Policy: Use a Content Security Policy (CSP) to define a set of rules that the browser should follow when loading resources for your extension. This will help prevent cross-site scripting (XSS) and other security vulnerabilities.
Use a Permission Model: Use a permission model for your Chrome Extension that only requests the minimum necessary permissions to access the external database. This will help prevent the extension from having too much access to the user's data.
Use a Secure Connection to the Database: Use a secure connection to the external database such as SSL/TLS, to encrypt the communication between the extension and the database. This will help prevent eavesdropping or tampering of data.
Use Role-based Access Control: Use role-based access control (RBAC) to define what actions different users can perform on the database. This will help ensure that only authorized users can access and modify the data.
Use Regular Security Audit: Perform regular security audits on your extension and the database, to ensure that all the best practices are being followed and that there are no vulnerabilities.
By following these best practices, you can ensure that your Chrome Extension has the correct permissions to access the external database, and that you are following best practices for securing and protecting user data.
Firebase
Firebase provides several security features that can help you handle user authentication and data protection for your Chrome Extension.
Authentication: Firebase provides a built-in authentication service that supports multiple authentication methods, including email and password, Google, Facebook, and more. It also supports OAuth2 and OpenID Connect to authenticate users and obtain access tokens.
Real-time Database Rules: Firebase provides real-time database rules that you can use to define the security rules for your data. This can help ensure that only authorized users can access and modify the data in the database.
Firebase Security Rules: Firebase provides security rules that you can use to define the security rules for your data, you can use these rules to define who can read and write data in your database. This can help ensure that only authorized users can access and modify the data in the database.
Firebase Authentication: Firebase provides a built-in authentication service that supports multiple authentication methods, including email and password, Google, Facebook, and more. It also supports OAuth2 and OpenID Connect to authenticate users and obtain access tokens.
Firebase Hosting: Firebase hosting provides a secure and fast way to host your web app, with automatic SSL certification, and global CDN.
Firebase provides a lot of built-in features that can help you handle user authentication and data protection for your Chrome Extension, it also has a lot of built-in security features that help to protect your data from unauthorized access, and it can also handle the heavy lifting of securely connecting to your backend services.
Users privacy
When building a chrome extension, it's important to consider user privacy and rights, and to make sure that you are only tracking the data that is necessary for the functioning of your extension and not collecting any unnecessary data.
Here are some things to consider when designing the tracking and data collection for your chrome extension:
Collect only the data you need: Only collect the data that is required to provide the functionality of your extension, and do not collect any unnecessary data.
Be transparent with users: Clearly communicate to users what data is being collected, why it is being collected, and how it will be used. Provide a privacy policy that explains this in detail.
Obtain user consent: Obtain user consent before collecting any data, and make it easy for users to understand and control their data.
Use secure storage: Use secure storage for any data that is collected, such as a secure database, to protect the data from unauthorized access.
Limit data retention: Limit the amount of time that data is retained, and delete data that is no longer needed.
Use encryption: Use encryption to protect data in transit and at rest.
Keep data anonymous: When possible, keep the data anonymous by using unique identifiers, rather than storing personal data.
Keep in mind the rights of the users: Such as GDPR and CCPA, and make sure you are in compliance with the regulations.
By following these best practices, you can ensure that your chrome extension respects user privacy and rights while collecting only the data that is necessary for the functioning of the extension.
Cost
The estimated cost of setting up a React Chrome Extension with a backend service, using technologies like JavaScript, Node.js, React, Firebase and an S3 bucket, will depend on various factors such as the specific services and resources you use, the amount of traffic your extension generates, and the size of your database.
Here's a rough estimate of the costs you can expect for each service:
JavaScript and Node.js: There is no cost associated with using JavaScript and Node.js to build your extension.
React: There is no cost associated with using React to build the front-end of your extension.
Firebase: Firebase offers a free Spark plan that includes a Realtime Database and Cloud Firestore, with limits on usage and storage. If your usage exceeds the free tier limits, you'll be charged for the additional usage. The pricing for Firebase can be found here:
S3: S3 charges for data storage, data transfer, and requests. The pricing for S3 can be found here:
AWS Lambda: Can be a cost-effective solution for running the code for your React Chrome Extension, especially if you expect to have low-to-medium traffic at the start, and your database is small. The pricing for Lambda can be found here:
API Gateway: Can be a cost-effective solution for running the code for your React Chrome Extension, especially if you expect to have low-to-medium traffic at the start, and your database is small. The pricing for API Gateway can be found here:

AWS Lambda is a serverless compute service that lets you run your code without provisioning or managing servers. You can use Lambda to execute your backend code in response to events such as an API request, a change in a database, or a file upload to S3. With Lambda, you only pay for the compute time you consume, and you don't have to worry about scaling, patching, or managing servers.
API Gateway is a fully managed service that makes it easy to create, publish, maintain, monitor, and secure APIs at any scale. You can use API Gateway to create RESTful, HTTP, and WebSocket APIs and handle the heavy lifting of securely connecting to your backend services, including Lambda, DynamoDB, and more.
It's important to keep in mind that the cost of running your code on Lambda or API Gateway will depend on the amount of traffic your extension generates, the number of requests, and the duration of the requests.
Keep an eye on the cost and usage of these services and adjust your usage accordingly.

Other factors
Scalability: It is important to ensure that the extension and the backend services are scalable. This includes using services that can automatically scale based on usage, and implementing caching mechanisms to improve performance.
Performance: It is important to optimise the performance of the extension, including the backend services, to ensure that the extension is responsive and can handle high traffic.
Monitoring and logging: It is important to monitor and log the usage and performance of the extension, and the backend services, to identify and troubleshoot issues, and to improve the overall user experience.

FAQ
Can I use Ubuntu?
Yes, it's possible to build and run a React Chrome Extension with a backend service using Ubuntu as the operating system.
You can use Ubuntu as your development environment and use technologies like JavaScript, Node.js, React, and Postgres to build your React Chrome Extension and its backend service.
You can use Node.js to write your backend code and run it on Ubuntu. You can then use a web framework like Express.js to handle the routing and API calls. Postgres can be installed and run on Ubuntu to use as a database.
For frontend, you can use React to build the extension and package it using webpack.
You can use AWS S3 bucket to store files and you can use AWS Lambda and API Gateway to run your backend code and handle API requests, this can be done with the AWS SDK for Node.js, which can be installed on Ubuntu to interact with the AWS services.
It's important to note that while it is possible to build and run your chrome extension with a backend service using Ubuntu, depending on the complexity of your project, it may be beneficial to use a managed service like AWS Lambda, API Gateway, and S3 bucket, as they can provide you with a more robust and scalable solution.
Additionally, it is important to have knowledge and experience of the technologies you plan to use and to consider the security and scalability of your solution.
Can I use Containers?
Containers are a powerful technology that can be useful for many types of applications, but for Chrome Extension, it's not necessarily required.
Chrome Extensions are client-side applications that run in the browser and interact with web pages. The typical use case for containers in a Chrome Extension is if you need to run a specific version of a library or runtime environment, or if you want to package your application and its dependencies together for easy deployment.
However, for a Chrome Extension, it's not necessary to containerize it, as long as you can package your code and dependencies together and deploy it as a Chrome Extension.
Using AWS Lambda and API Gateway as your backend service, and storing your files in S3 bucket, you can achieve the desired functionality without the need to containerize.
However, depending on the complexity and scalability of your chrome extension, you may want to consider containerization in the future if it becomes necessary.
It's important to keep in mind that the choice of whether or not to containerize your chrome extension will depend on your specific requirements and the resources you have available.

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