Open Source Browser Extensions
Browser extensions add features to web browsers or adapt how websites behave, helping people improve privacy, customize interfaces, automate routine tasks, and access tools without leaving a page. They typically run with permissions to read or change browsing data, so their design and security practices matter as much as their features. Many use web technologies and browser extension APIs, with compatibility varying across browsers and versions.
Open source options include content blockers, password and privacy tools, accessibility aids, research utilities, productivity features, and integrations with online services. When choosing one, review its license, permission requests, maintenance activity, browser support, and data handling practices. Check whether it depends on external services or specific software, and whether its features fit your workflow. These tools can be useful for everyday users, developers, researchers, and organizations seeking control over their browsing experience.
21 repositories · updated October 13, 2026
maskit: Locally Mask Sensitive Data Before AI Requests
Maskit is a local privacy gateway that replaces sensitive information in AI requests with consistent placeholders, then restores it in responses. It is aimed at developers using AI coding tools or web assistants who want a configurable layer between their data and model providers.
NewHealth 61/100
OpenWebAgent: Build LLM-Powered Web Browsing Agents
OpenWebAgent combines a Chrome extension with a configurable server to let LLM-based agents interpret webpages and take actions. It suits developers prototyping browser agents who can operate and maintain the server stack themselves.
InactiveHealth 17/100
GHunt: Investigate Google Accounts and Assets with OSINT
GHunt is a Python framework for investigating Google-related data, including email addresses, Gaia IDs, Drive files, and BSSIDs. It suits OSINT researchers and authorized investigators who need CLI or library workflows with JSON export.
QuietHealth 35/100
scramble: Improve Writing with AI in Your Browser
Scramble is a Chrome extension that applies AI prompts to selected text on webpages. It suits people who want customizable writing help and a choice of hosted or local LLM providers instead of a fixed editing workflow.
InactiveHealth 21/100
opendia: Connect AI Models to Your Browser
OpenDia is an MCP server and browser extension that lets compatible AI clients inspect and control your existing browser. It suits people who want local browser automation across their logged-in sessions, tabs, and pages.
ActiveHealth 60/100
chrome-extension-boilerplate-react-vite: Build Browser Extensions with React
A TypeScript starter for building Chrome and Firefox extensions with React and Vite. It provides a modular setup for extension pages, shared packages, development reloads, and browser testing, but is archived and read-only.
ArchivedHealth 33/100
Addon: Remove Tracking Parameters from Browser URLs
ClearURLs is a Firefox- and Chromium-based browser extension that strips tracking elements from URLs. It also offers link-cleaning tools and several protections against browser-based tracking, but its recent development activity is limited.
InactiveHealth 30/100
read-frog: Learn Languages While Reading the Web
Read Frog is a browser extension for language learners who want translation and AI-assisted study tools alongside everyday web reading. It supports multiple AI providers, selection and subtitle translation, text-to-speech, and flashcards.
ActiveHealth 80/100
SponsorBlock: Skip Sponsor Segments in YouTube Videos
SponsorBlock is a crowdsourced browser extension that automatically skips sponsor segments and other marked sections in YouTube videos. It suits viewers who want community-submitted skips across supported browsers and related clients.
ActiveHealth 56/100
Screenity: Record and Annotate Your Screen in Chrome
Screenity is a privacy-focused Chrome extension for recording screens, cameras, and audio, with annotation and basic video editing. It suits people making tutorials, demos, or feedback videos who want a free, no-sign-in workflow.
ActiveHealth 36/100
page-assist: Use Local AI Models While Browsing
Page Assist is a browser extension that brings local AI chat into a sidebar or web UI, including questions about the page you are viewing. It supports Ollama, Chrome AI, and OpenAI-compatible endpoints.
ActiveHealth 58/100
mitaka: Search and Scan OSINT Indicators in Your Browser
Mitaka is a browser extension for identifying and looking up domains, IPs, hashes, CVEs, and other OSINT indicators. It refangs selected text and routes it to supported search and scanning services.
ActiveHealth 43/100