Best Browser Extensions in 2025

Reduce eye strain in your browser with this extension that provides a dark theme for browsing.

Key Dark Reader features:

Eye Strain Reduction Customizable Settings Improved Battery Life Open Source

Open Source

Flagsmith lets you manage feature flags and remote config across web, mobile and server side applications. Deliver true Continuous Integration. Get builds out faster. Control who has access to new features. We're Open Source.

Key Flagsmith features:

Feature Flags Remote Config A/B/X Testing & Optimization Organization Management

Try for free Open Source freemium

Greasemonkey compatible script manager.

Key Tampermonkey features:

User-Friendly Interface Cross-Browser Support Sync Capabilities Wide Range of Scripts

Violentmonkey is a userscript manager to support running userscripts in web pages.

Key Violentmonkey features:

Free and Open Source Active Development Cross-Browser Support User Script Manager

Open Source

EXPRESSIVE, DYNAMIC, ROBUST CSS.

Key Stylus features:

Simplified Syntax Extensive Feature Set Preprocessor Enhancements JavaScript Interoperability

Open Source

Stylus is a userstyles editor and manager based on the source code of Stylish version 1.5.2.

Key Stylus - User Styles Manager features:

Customization Ease of Use Open Source CSS Preprocessor Support

Open Source

Change the appearance of websites instantly. Preview and install styles created by other users on stylebot.me.

Key Stylebot features:

User-Friendly Interface Customization Real-Time Changes Community-Driven

Open Source

A site for user scripts.

Key Greasy Fork features:

Wide Selection of Scripts Open Source and Community-Driven Ease of Use Free to Use

Night Eye is a browser extension that enables dark mode on any website you visit. It does not ruin your browsing experience by simply inverting images.

Key Night Eye features:

Improved Readability Customizable Settings Wide Browser Support Automatic Scheduling

Accessible color schemes for all websites.

Key Midnight Lizard features:

Customizable Color Schemes Improved Readability Cross-Platform Compatibility User-Friendly Interface

Open Source

Browser Superpowers for your AI Agents: Automate tasks, extract data, create AI web tools, and manage MCP servers in your browser or across millions of them. Secure, private, and scalable.

Customize the way a web page displays or behaves, by using small bits of JavaScript.

Key Greasemonkey features:

Customization User Community Open Source Cross-Platform Compatibility

Open Source

Agile goal and performance management.

Key Momentum features:

Visual Appeal Focus and Productivity Customization Integrated Tools

Puppeteer is a Node library which provides a high-level API to control headless Chrome or Chromium...

Key puppeteer features:

Headless Browsing Full Browser Control Rich API Active Community