Staff Engineer — Pigment CSS at MUI

Research, build, document, and help ship a next-gen zero-runtime CSS-in-JS library with a focus on performance and great developer experience.

Details of the role

• Location: Remote (preference for UTC-6 to UTC+5).

• Type of work: Full-time (contractor or employee depending on circumstances).

• Level: 5 or above.

• We're a remote company, we prefer asynchronous communication over meetings.

The company

MUI's story began in 2014 with Material UI, the most successful React implementation of Google's Material Design. Today, Material UI stands as one of the most popular open-source libraries on GitHub and has paved the way for the fully-fledged startup known as MUI (founded in 2019), which now boasts an ever-expanding ecosystem of React UI products. We're a company of 31+ people as of late 2023, and we're growing.

The products

MUI is best known for our flagship product, Material UI—but this is just one of three core component libraries we maintain. Base UI is our headless component library, and Pigment CSS is a zero-runtime CSS-in-JS library, that is a replacement of the current styling engine that uses emotion/styled-components under the hood. We also host Design Kits and pre-built Templates.

Beyond the core libraries, MUI X offers advanced components like the Data Grid, Date and Time Pickers, and Charts, for more complex user interactions and data visualization needs.

We're also making ambitious moves to incorporate our full suite of components into Toolpad, a low-code admin builder tool for assembling full-stack apps faster than ever.

Learn more about MUI's products in this blog post: An introduction to the MUI ecosystem.

The culture

MUI is a fully remote company with a team that spans the globe. The majority of our work is asynchronous, and we rely on written communication to collaborate. We're radically transparent: nearly all of our work happens in public. Each contributor has the freedom to decide how and when they work, and that work is primarily self-directed: it's your responsibility to define and complete your own tasks in a timely manner.

For additional details about the culture, you can check our careers and about pages and also our public Handbook.

Why we're hiring

We believe CSS-in-JS is the best styling API with the best developer experience for writing CSS. We've used it in Material UI since v1 (back then, with JSS, and currently with Emotion in v5). However, there are key challenges we need to overcome to keep using this stack: improving performance and compatibility with React 19 features, including React Server Components. That's why, about a year ago, we started to work on Pigment CSS! We recently released an early alpha version, introduced at React Conf 2024, for which we're seeing early positive adoption and some community validation.

This is just the beginning, though. There's so much to do to make Pigment CSS a reliable and mature option for the future of Material UI and for many developers looking for a next-generation CSS-in-JS styling engine. We're well-positioned to make this happen, so we're looking for a talented engineer to join the team and help us get further beyond!

Why this is interesting

The core components that will depend on this library are widely used, you will receive a lot of feedback on your work. The community has high expectations, they will push you to do better, every day.

Our products empower React developers to build awesome applications faster – we see millions of developers on MUI's docs every year, one million a month.

The role

Key responsibilities

• Build. You will provide solutions for integrating the library with various bundlers and frameworks. You will build new features and improve the DX of the library.

• Nurture community contributions. You will provide guidance and direction to unlock the contributions of the community. Your time will often be way better spent doing this than fixing the problems yourself.

• Shape the product. You will be laser-focused on the end goal. It's not about solving technical challenges but about the problems solved for the users.

• Keep technical debt in check. You will make sure we can keep shipping features at a reasonable pace, align the team on "one way" of doing things and make sure engineers follow the conventions.

• Be a solver. You will dig deep into arbitrarily complex problems and find an appropriate path forward. Some focus on a given area for long periods, others bounce from hotspot to hotspot as guided by organizational leadership.

The best parts of this job

• You'll be at the cutting edge of application development — working on one of the fastest-growing CSS-in-JS libraries on the market.

• You'll be part of an active, open, friendly community of developers that are excited about building awesome applications.

• Your role will be key to making MUI the go-to UI solution for building applications, websites, and design systems that does not have to trade performance for a great developer experience.

The worst parts of this job

• Shifting context. You will necessarily have to shift context and dive into a different feature before the current one is done. It may even be in an area of the codebase you're unfamiliar with or don't have a ton of understanding about. It's fun, rewarding work, but it can be very challenging.

• We move quickly but don't sacrifice quality. We ship early, often, and quickly. You may not be initially comfortable with the cadence with which we ship high-quality features and improvements to end-users. By doing so, we sacrifice on solving each problem 100% in exchange for fast feedback. Solving 50-70% of the issue with quality should be enough for any given iteration. Our users quickly tell us when we haven't pushed a solution far enough.

• MUI has a large codebase. You may bang your head against the wall at times, and then write tests to assist future you 😌. The work you will be doing is somewhat unique and idiosyncratic. You probably have not had a similar role before.

• In open-source, you're faced with a nonstop stream of bug reports and support requests. That means you need to develop an intuition for when to ignore something, and when to dig in further.

Who we're looking for

We're looking for someone with strong core JavaScript skills. More important than specific technical skills though is that you're a strong problem solver who loves to learn. Details matter to you.

Required

• Expertise in the modern JavaScript ecosystem. Pigment CSS is built on the shoulders of giants, you need to use technologies such as TypeScript, Node.js, Babel, Rust, or SWC.

• A track record of demonstrating an eye for product and solving real-world user problems. If you have a knack for solving problems at the root cause, shipping beautiful user interfaces and intuitive APIs, we want you on our team.

• Experience building and shipping production code in a team setting with a passion for writing tested, performant, and high-quality code.

• Strong written and verbal communication skills. As part of the team, you'll interface both directly and indirectly with community members and enterprise customers, and contribute to user documentation. Clear communication is fundamental in creating intuitive and compelling resources.

• Ability to dive into complex problems. You should be able to quickly assess, understand, and iterate upon aspects of our codebase.

• Ready and willing to ask and answer questions. If you're comfortable saying you're unsure, asking for help; but equally reaching out to assist others, you'll be an incredible addition to our team. We thrive because of continuous learning. First-time mistakes should be celebrated, not blamed.

• Leadership skills. You will help build the community and collaborate with it. You will guide and mentor contributors, steering the community in the right direction.

• Past work with front-end infrastructure. Perhaps you've written a Babel plugin or even worked on a problem similar to the ones Pigment CSS aims to address. It would be great if you could address this in your cover letter!

Nice to have (but not required)

• You've maintained an active repository before. Maybe you've helped maintain a popular open-source repository, or perhaps you've worked on internal repositories that saw contributions from multiple teams. Previous experience with highly active repository workflows is a definite plus for this role.

• You have contributed code to a CSS-in-JS library. A history of contributing to a CSS-in-JS library is a plus.

Benefits and compensation

Competitive compensation depending on the profile and location. We are ready to pay top market rates for a person who can clearly exceed the role's expectations. You can find the other perks & benefits on the careers page.

Don't meet every requirement? Apply anyway! Research shows that certain folks are less likely to apply for a role than others unless they meet 100% of the outlined qualifications. If this role excites you, we want to hear from you. We'd love for you to share the unique skills, passion, and experience you could bring to MUI.