Manifest.json Versions Explained
MV1, MV2, and MV3
Every browser extension depends on a file called manifest.json. This file defines how an extension behaves, what permissions it needs, and how it interacts with websites. Over time, Chrome introduced multiple manifest versions to improve security, privacy, and performance.
What Is Manifest.json?
manifest.json is the core configuration file of any browser extension. It tells the browser essential information such as:
- Extension name and version
- Permissions it requires
- Background scripts or service workers
- Content scripts and UI elements
- Icons and extension behavior
Without this file, an extension cannot be installed or executed.
Manifest Version 1 (MV1)
Manifest V1 was the earliest version used in Chrome extensions.
- Very basic structure
- Limited security controls
- No longer supported by modern browsers
Status: Fully deprecated and not usable today.
Manifest Version 2 (MV2)
Manifest V2 became the standard for many years and powered most popular extensions.
- Persistent background pages
- Powerful webRequest API
- Flexible permissions system
- Widely used by ad blockers and privacy extensions
However, MV2 allowed too much unrestricted access, which led to privacy and performance concerns.
Status: Being phased out by Chrome.
Manifest Version 3 (MV3)
Manifest V3 is the latest and currently required standard for Chrome extensions. It focuses on user safety, privacy, and efficiency.
- Background pages replaced with service workers
- declarativeNetRequest instead of blocking webRequest
- Stricter permission controls
- Improved performance and battery usage
While MV3 limits some advanced behaviors, it creates a safer ecosystem for users.
Manifest V2 vs Manifest V3
- MV2: More control, less security
- MV3: More security, rule-based control
- MV3: Better performance and privacy
Why Manifest Version Matters
The manifest version directly impacts:
- Extension performance
- User privacy and security
- Long-term compatibility with Chrome
- How ad blockers and privacy tools work
Extensions built on Manifest V3 are more future-proof and trusted by browsers.
Final Thoughts
The evolution from MV1 to MV3 shows how browser extensions are becoming safer and more efficient. While Manifest V2 played a major role in extension history, Manifest V3 is the future.
At Extension Bazaar, we encourage modern, secure extensions that respect user privacy and follow the latest browser standards.
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