Senior Software Engineer, molab

CoreWeave is The Essential Cloud for AI™. Built for pioneers by pioneers, CoreWeave delivers a platform of technology, tools, and teams that enables innovators to build and scale AI with confidence. Trusted by leading AI labs, startups, and global enterprises, CoreWeave combines superior infrastructure performance with deep technical expertise to accelerate breakthroughs and turn compute into capability. Founded in 2017, CoreWeave became a publicly traded company (Nasdaq: CRWV) in March 2025. Learn more at www.coreweave.com.

What You’ll Do:

At marimo, we’re on a mission to make the world’s best open-source programming environment for working with data, together with a world-class, scalable, and performant cloud-hosted counterpart. marimo is a reinvention of the Python notebook — it feels like a next-gen reactive Python notebook, but is stored as pure Python that can be versioned with Git, deployed as a data app, run as a script, and reused as a module. Incubated initially with scientists at Stanford, marimo is now used by leading companies, labs, and universities around the world, with millions of downloads since launch and over 17,000 stars on our GitHub repository.

On the marimo team, we believe that the tools we use shape the way we think — better tools, for better minds. If you're passionate about developer tools, thrive in ambiguity, enjoy solving challenging engineering problems at scale, and yearn for greenfield problems, you'll fit right in.

The molab team develops a cloud-hosted marimo notebook service called molab. molab lets anyone in the world experiment with data, build interactive apps, and share their work for free, all using the open-source marimo notebook and accelerated by AI-assisted coding. This is a high impact team and product, undergoing rapid growth and working on many challenging greenfield problems — with an emphasis on building highly available, low latency and fault tolerant systems.

About the role:

As a senior engineer on marimo's molab team, you will help design and implement the backend architecture of molab, solving for high availability, low latency (both the ability to rapidly spin up and spin down notebook kernels on demand, as well as low latency communication between the notebook frontend and backend), stability, and fraud and abuse. You will also be involved in building product features as needed, such as secret management.

Who You Are:

• 5+ years of experience in software engineering