How to Build a Modern Chrome Extension with Manifest V3 Best Practices

Browser extensions are one of the fastest ways to build high-impact tools using the frontend skills you already have (HTML, CSS, and JavaScript).

However, if your experience was based on Manifest V2, building extensions in 2026 requires adapting to Manifest V3 (MV3) standards—including event-driven service workers, stricter Content Security Policies (CSP), and promise-based Chrome APIs.

What’s Covered in This Guide:

1. Structuring manifest.json under Manifest V3 specifications
2. Designing popup UIs and styling with modern CSS
3. Working with event-driven background service workers
4. Injecting and managing content scripts safely
5. Cross-component messaging via chrome.runtime.sendMessage
6. Managing persistent state using chrome.storage.local

Check out the full tutorial and code snippets on SunnyWriteUps.