How to create a Google Chrome extension?
If you’re a Google Chrome user, you probably have extensions: these are programs you can install to modify the functionality of your browser.
For example, Chrome extensions can help you automate specific tasks in your browser, change existing behaviors, or make your software more comfortable. There are even extensions for Chrome that can help you improve the SEO of your website.
How does a Chrome extension work?
The only difference between a Chrome extension and a regular website is that extensions contain a “manifest” file, which gives them a specific function to perform.
How to create a Google Chrome extension
It may seem obvious, but not everyone uses Chrome as a browser: if you’re not a Chrome user, make sure you install it before you proceed.
Throughout the process, be sure to check your work frequently. Correcting coding errors as you go along rather than at the end will be easier.
Let’s get started!
Step 1: Determine the needs of your Chrome extension
The first step in creating your Chrome extension is to define a feature.
What will it do? What will it look like? Some extensions work with a cloud service and provide additionnal features (like VPN extensions for example), while others are standalone applications that can provide you with easy access to the WHOIS records of a domain for example.
An icon is also needed to appear in the Google Chrome Store. All icons must be square, and otherwise, they may be distorted. If you don’t provide an icon, Chrome will add one for you by default.
Let’s assume that if you’re reading this article, you already have your application and the service it should provide in mind and move on.
Step 2: Create a directory for your Chrome extension
Every project has its folder! To begin, you must create a new directory that will host all your extension files.
This is important because, for Chrome to load your plugin, it must be directed to a single folder containing all your extension files. You will add all the files you need for your extension to this folder.
Step 3: Create the manifest.json file for your extension
The next step is creating the manifest file for your extension: this is the file that tells Chrome how to load the extension correctly, which is very important! Without it, the button to install the extension is missing.
Create a file called “manifest.json” and add it to your directory, then add the code you need, which will tell the browser the name, icons, and where to find the features of your extension.
Step 4: Load your extension into Chrome and check for errors.
Now it’s time to test your extension to make sure Chrome is running it correctly:
Go to chrome://extensions in your Google Chrome browser.
Check the “Developer mode” box in the upper right corner.
Click “Load unpackaged extension,” which will display a file selection dialog box.
If your extension is valid, it should load immediately. If it is not valid, you will see an error message at the top of your page. In this case, check for errors, correct them and try to load your extension again.
The most common errors are syntax errors. Check all your commas and brackets and make sure they are formatted correctly. If you can’t find the errors in your file, you can get a developer to create your extension.
Step 5: Develop your script
Next, you will need to add a script to tell your extension what to do.
First, create a file called background.js in your extensions directory, and put your script there.
Then, go back to your extension’s management page and click “reload.”
Be sure to add the scripts to your manifest file.
Step 6: Create your user interface
Your extension can have several types of user interfaces, from pop-ups to tooltips and more.
Again, you must declare this code in your manifest to be considered.
Step 7: Use the Chrome APIs
In this step, we’ll dive into the most helpful tool in your development process: the Chrome APIs found on the developpers portal.
These APIs allow you to :
- request user permissions,
- listen and react to events,
- store user data,
- interact with the browser
- access unique features such as Bluetooth, audio, and notifications
You can browse the Chrome API Documentation and find APIs that may be relevant to your extension.
Step 8: Test your Chrome extension
Like A/B testing in marketing, it’s essential to test your extension to ensure everything works.
Test it yourself first, of course. Then get someone else to do it, and do it without giving them specific instructions, to make sure it’s intuitive to use.
Make any necessary changes, and then test your extension again.
You can still optimize and improve your extension even after launching it.
We hope this guide explains to you how to create a Chrome extension. Now you will need to get it published!