Senior Frontend Infrastructure & Performance Engineer

Slack, San Francisco

Slack's cloud-based collaboration tools and services are used worldwide.

People love working on Slack — it is a complex web application used by millions of people for hours or even days at a time. Our engineering team is tasked with keeping it fast and reliable, and maintaining the systems that the rest of our frontend team uses to build their features.

We’re looking for a Senior Software Engineer with experience in behind-the-scenes JavaScript to get the job done — if you’re more interested in wrangling WebSockets than writing CSS, you’ll fit right in here. We love performance optimization, writing unit tests, improving maintainability, and iterating on best-practices with the rest of the frontend teams. We also work with backend infrastructure engineers to design new services to better support Slack clients.

Our work depends on working closely with other teams at Slack, so communication and collaboration skills are a must. This is an opportunity to work on a small team that directly affects how Slack’s desktop web client is built.

This position is based in San Francisco and reports to one of our engineering managers.


  • You know the weirdest parts of JavaScript and love working with it anyway.
  • You know your way around the performance profiling and debugging tools in your web browser of choice.
  • You’re up to speed with WebSockets, Fetch, Promises, ES6, and beyond.
  • You’ve worked with React (or at least understand why it’s important). Familiarity with Redux and Lodash will also come in handy.
  • You’ve been working with front end frameworks and libraries professionally for 5+ years (and having built or contributed to some is a big plus.)
  • Diving into a new system to understand mysterious behavior excites you.
  • You write understandable, testable code with an eye towards maintainability and scalability.
  • You are a strong communicator and are equally comfortable talking with your immediate team, other frontend engineers, or even backend infrastructure engineers.
  • You are ready to learn, but just as excited to teach.
  • You understand that the perfect solution is informed by the people who will be building on your work, rather than being purely dependent on technical merits. Empathy is a feature.
  • You have a bachelor's degree in Computer Science, Engineering or related field, or equivalent training, fellowship, or work experience. 

About Slack

Empathy. Courtesy. Playfulness. Craftsmanship. Solidarity — these are some of the values we live by, as a company. We work by them, too: we’re building a platform and products we believe in — knowing there is real value to be gained from helping people, wherever they are, simplify whatever it is that they do and bring more of themselves to their work.

We’re building a strong, diverse team of curious, creative people who want to find a purpose in their work and support each other in the process. We work hard and we play to win… within normal business hours. And then we go home.

That balance is important: It enables us to truly do the best work of our lives. As a result, we create a place where all kinds of work happens — and happens well — all while working alongside people we respect and admire.

Want to learn more about Slack? Visit Slack's website.