How to Make a Chrome Extension — A 2026 Guide

Two ways to make a Chrome extension

There are two practical paths in 2026.

The first is the traditional path — hand-write the manifest, the content scripts, the background worker, the popup. This requires JavaScript fluency, familiarity with Chrome's extension APIs, and patience with Manifest V3's quirks. Time investment for a basic working extension: 4–8 hours for an experienced developer, longer for beginners.

The second is the AI path — describe what you want in plain English, an AI generates the full Manifest V3 package, you load it into Chrome. Time investment: 3–5 minutes total. No coding required.

This guide covers both. If you want to learn the underlying tech, follow the manual path first to understand the pieces. If you just want a working extension, jump to the AI path.

Path A — Make a Chrome extension by hand (the long version)

Step 1: Set up the project folder. Create an empty folder. Inside it, create three files: manifest.json, popup.html, and popup.js.

Step 2: Write the manifest. manifest.json is the entry point Chrome reads first. Minimum content:

{
  "manifest_version": 3,
  "name": "My Extension",
  "version": "1.0",
  "description": "What this extension does",
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icon16.png",
      "48": "icon48.png",
      "128": "icon128.png"
    }
  },
  "permissions": [],
  "host_permissions": []
}

Adjust permissions based on what your extension needs to do. storage for data persistence. activeTab for accessing the current tab. tabs for managing multiple tabs. notifications for browser notifications. Add host permissions like "https://*.example.com/*" for cross-origin requests.

Step 3: Build the popup UI. popup.html renders when the user clicks the extension icon. Standard HTML, plus a script reference. Cannot use inline onclick= handlers — Manifest V3 CSP forbids inline scripts.

Step 4: Add a content script (if needed). If your extension modifies webpages, you need a content script. Create content.js and reference it in manifest.json:

"content_scripts": [{
  "matches": ["<all_urls>"],
  "js": ["content.js"]
}]

Step 5: Add a service worker (if needed). For background logic, alarms, or long-lived state, add a service worker. Service workers in V3 are not persistent. They're killed after inactivity. Use chrome.storage for state.

Step 6: Generate icons. Chrome requires PNG icons at 16×16, 48×48, and 128×128. Save as icon16.png, icon48.png, icon128.png in the extension folder.

Step 7: Load it into Chrome. Open chrome://extensions. Toggle "Developer mode" in the top right. Click "Load unpacked." Select your extension folder. The extension installs and the icon appears in your Chrome toolbar.

Step 8: Iterate. Test the extension. Find bugs. Edit code. Click the "Refresh" button on your extension card in chrome://extensions to reload the changes.

Step 9: Publish. When the extension works: zip the folder. Pay the $5 Chrome developer fee. Upload the zip. Fill in store listing details. Submit for review. Most reviews complete within 1–7 days.

Path B — Make a Chrome extension with AI (the short version)

PlugThis collapses Path A into three steps:

Step 1: Open PlugThis. Type a description of what your extension should do — what it does, which sites it runs on, what UI it has, what data it remembers.

Step 2: PlugThis generates the full Manifest V3 package — manifest, content scripts, popup, service worker, icons — in 60–90 seconds.

Step 3: Download the zip. Load it into Chrome via chrome://extensions → Developer mode → Load unpacked.

Done. Total time: 3–5 minutes.

When to use which path

Use Path A (hand-coded) when:

• You want to learn how Chrome extensions actually work
• You have a complex extension with niche requirements
• You're a developer and prefer writing code over describing it
• You're contributing to an existing extension codebase

Use Path B (AI) when:

• You want a working extension fast
• You don't know JavaScript or Chrome APIs
• You're prototyping and iteration speed matters
• You have lots of extension ideas and want to validate them quickly

Most people benefit from Path B for the build, then Path A for understanding. Build with PlugThis, then read the generated code if you want to know what it's doing.