CRXJS Maintainers & Contributors

Custom Browser Extensions That Automate Your Workflow

We build Chrome and Edge extensions that integrate with your existing tools, automate repetitive tasks, and save your team hours every day. Built by the people who maintain the tools other developers use to build extensions.

100+
Extension versions shipped
3.9k+
GitHub stars (CRXJS)
MV3
Manifest V3 native

Why We Build Better Extensions

We don't just use the tools - we build them. Our team contributes to CRXJS and has built an internal library that powers all our extension projects.

CRXJS Maintainers & Vite Plugin Authors

We are contributors to CRXJS - the Vite plugin for Chrome extensions created by Jack and Amy. We specialize in writing Vite plugins, so we know the internals of extension build tooling because we help build it.

react-content-script-injector

Our internal library built specifically for injecting React UIs into complex SPA applications. It automatically monitors injection points, handles client-side route changes, and re-mounts components when the host app re-renders. It also handles React Portals so that the full React context is always available - even inside Shadow DOM or injected panels. Real-time error reporting across users means feature flags and A/B tests on the host site never break your extension. Static sites are easy - we specialize in the hard part: React and SPA apps.

Production-Proven Stack

Vite 8 + CRXJS + React + TypeScript with hot module replacement, and TanStack Query for industry-standard data caching and fast access. We run on the latest Vite with backward support for v3 through v8 - so your extension always builds on a proven, up-to-date toolchain. Faster development, fewer bugs, and extensions maintainable for years.

How We Build Your Extension

From idea to Chrome Web Store in weeks, not months.

01

Discovery & Scoping

We analyze your workflow to identify where a browser extension can save the most time. We map out the pages, APIs, and integrations involved.

02

Architecture & Prototyping

Using CRXJS and our react-content-script-injector library, we set up the project with HMR, TypeScript, and a component architecture that scales.

03

Development & Testing

We build iteratively with weekly demos. Content scripts, background workers, popup UIs - covered by end-to-end, integration, and unit tests, then validated across Chrome and Edge with real-world data.

04

Deployment & Maintenance

CI/CD that automatically bumps versions, builds, and deploys to the Chrome Web Store on every merge. Custom installer apps push new builds to QA testers' machines automatically from GitHub. Enterprise sideloading via group policy. We handle updates, Chrome API changes, and Manifest V3 migrations.

Extensions We've Built

Real extensions solving real business problems for e-commerce companies and agencies across Europe.

Allegro Ads Manager

Campaign management extension for Allegro Ads agencies. Automates bid adjustments, bulk operations, and reporting directly from the browser.

Allegro AdsReactAutomation

FBA MultiTool Extension

Browser extension for Amazon FBA sellers using fbamultitool.com. Injects product research data, profit calculations, and supplier insights directly into Amazon product pages.

Amazon FBAProduct ResearchInjected UI

Our Extension Tech Stack

Only the latest and battle-tested libraries - industry-standard tools that ensure fast builds, reliable caching, and long-term maintainability.

CRXJS
Build Tool
React
UI Framework
TypeScript
Type Safety
Vite 8
HMR & Bundling (v3-v8)
Manifest V3
MV3 Native
Shadow DOM
Style Isolation
Tailwind CSS
Styling
E2E & Unit Tests
Quality Assurance
TanStack Query
Data Caching
Plasmo / WXT
Alternatives

Ready to Build Your Extension?

Whether you need a simple productivity tool or a complex enterprise extension, we have the experience and tooling to deliver it right.

Get in touch

Have a project in mind? Let's discuss how we can help.

Or book a call directly: