Senior Software Engineer, Frontend/Fullstack

The marimo core open source team develops and maintains the marimo open source notebook. Today, this includes the marimo editor frontend, the marimo backend which includes the core dataflow compiler and runtime, an intermediary server, the marimo library, and an ecosystem of related projects, such as a VS Code extension, codemirror extensions, and more. This team has the crucial role of shepherding the future of one of Python's fastest growing and most impactful open-source projects.

As a senior software engineer on marimo's core open source team, you’ll take ownership of projects across marimo's open-source ecosystem, with an emphasis on marimo's frontend, servers, and editor extensions (such as VS Code and Cursor). You will design delightful and powerful interactive experiences in the marimo editor, while making sure that the user interface remains simple; you will also lead building scalable and performant data visualizations, a robust code editing experience, and other related tasks. You'll work in the open, at a fast pace — engaging promptly and empathetically with a large and vocal community of users and contributors, triaging their issues and reading between the lines to understand their unstated needs. All the while, you'll exercise judgment to balance the needs of our community with the team's roadmap, opinionated vision, and taste.

• 4+ years of experience in software engineering

• Proficiency in Typescript, strong fundamentals that are language agnostic

• Experience building modern React applications

• Strong communication skills, written and verbal

Preferred Qualifications:

• A passion for and experience building developer tools, especially for AI, ML, or data

• A passion for working with data, with the ability to empathize with practitioners and researchers in AI, ML, data engineering, NLP, or other quantitative work

• An eye for visual and interaction design, with an emphasis on simplicity

• You find enjoyment in connecting with users and community daily

• Proficiency in Python, or a willingness to learn

• Experience with AI engineering, including MCP and agents

• Experience with SQL, databases, and data engineering

• Experience working on open-source projects

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.