Senior Software Engineer, Core Open-Source- Marimo

As a senior software engineer on marimo's core open source team, you'll take ownership of projects across marimo's open-source ecosystem, focusing on marimo's Back End and its Python ecosystem. You will influence critical decisions on library design, ensuring our APIs remain simple yet composable; you'll also design new capabilities that push the boundaries of interactive computing without complicating the user experience. 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 will exercise judgment to balance the needs of our community with the roadmap and vision. Description of the Team

The marimo core open source team develops and maintains the marimo open source notebook, including the editor frontend, Back End (data flow compiler and runtime), an intermediary server, the marimo library, and related projects such as a VS Code extension and CodeMirror extensions. Who You're a Great Fit If

• 4+ years of experience in software engineering.
• Proficiency in Python, with strong fundamentals that are language agnostic.
• Proficiency in computer systems, including parallel computing (threading, multiprocessing), concurrency (asynchronous programming), basic networking/inter-process communication.
• Experience in library design and/or open-source development.
• Strong communication skills, written and verbal.

Preferred

• 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.
• Enjoyment in connecting with users and community daily.
• Proficiency in Typescript, or a willingness to learn.
• Experience with AI engineering, including MCP and agents.
• Experience with SQL, databases and data engineering.
• Experience with at least one systems language, such as C or Rust.

You Might Be A Good Fit If

• You love crafting developer tools, especially for AI, ML, or data.
• You're curious about the day-to-day work of AI/ML/data engineers, researchers, and scientists.
• You enjoy building in the open and engaging with your users.

Base salary range: $165,000 to $242,000. The starting salary will be determined based on job-related knowledge, skills, experience, and market location. Total rewards include a discretionary bonus, equity awards, and a comprehensive benefits program (all based on eligibility).

Benefits include:

• Medical, dental, and vision insurance - 100% paid by CoreWeave.
• Company-paid Life Insurance.
• Voluntary supplemental life insurance.
• Short- and long-term disability insurance.
• Flexible Spending Account.
• Health Savings Account.
• Tuition Reimbursement.
• Participation in Employee Stock Purchase Program (ESPP).
• Mental Wellness Benefits through Spring Health.
• Family-forming support via Carrot.
• Paid parental leave.
• Flexible, full-service childcare support with Kinside.
• 401(k) with generous employer match.
• Flexible PTO.
• Catered lunch each day in office and data center locations.
• A casual work environment.
• A work culture focused on innovative disruption.

Workplace

We prioritize a hybrid work environment. Remote work may be considered for candidates located more than 30 miles from an office, on a case-by-case basis. New hires will be invited to attend onboarding at a hub within the first month and teams meet quarterly to support collaboration. Equal Opportunity Employer

CoreWeave is an equal-opportunity employer committed to fostering an inclusive and supportive workplace. All qualified applicants and candidates will receive consideration for employment without regard to race, color, religion, sex, disability, age, sexual orientation, gender identity, national origin, veteran status, or genetic information.

CoreWeave will ensure that qualified applicants and candidates with disabilities receive reasonable accommodations for the hiring process, unless an accommodation would cause an undue hardship. If a reasonable accommodation is needed, please contact (see below) Export Control Compliance

This position requires access to export-controlled information. To conform to U.S. Government export regulations applicable to that information, applicants must be U.S. persons or otherwise eligible under the applicable statutes. Location New York, NY, United States of America Industry IT Rate $165k - $242k Company CoreWeave

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.