Senior Software Engineer, Core -Source; frontend​/fullstack

Senior Software Engineer, Core Open-Source (frontend/fullstack) - Weights & Biases

Core Weave, the AI hyperscaler, acquired Weights & Biases to create the most powerful end‑to‑end AI platform. Since 2017, we’ve built an expanding footprint of data centers across the US and Europe. By combining core infrastructure with best‑in‑class tools used by over 1,500 organizations—including AstraZeneca, Canva, Cohere, OpenAI, Meta, Snowflake, Square, Toyota, and Wayve—we’re setting a new standard for how AI is built, trained, and scaled.

We’re looking for bold thinkers and agile builders who are excited to shape the future of AI alongside us. If you’re passionate about solving complex problems at the intersection of software, hardware, and AI, there’s never been a more exciting time to join our team.

On the marimo team, we believe the tools we use shape how we think. The marimo core open‑source team develops and maintains the marimo notebook, including the editor frontend, backend compiler/runtime, intermediary server, library, and related projects such as a VS Code extension and Code mirror extensions.

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 the frontend, servers, and editor extensions (e.g., VS Code and Cursor). You will design delightful and powerful interactive experiences in the marimo editor while keeping the UI simple, build scalable and performant data visualizations, and deliver a robust code‑editing experience.

You’ll work openly at a fast pace, engaging with a large, vocal community, triaging issues, and balancing community needs with the roadmap.

• 4+ years of experience in software engineering
• Proficiency in Typescript and core language‑agnostic fundamentals
• Experience building modern React applications
• Strong written and verbal communication skills

• Passion for building developer tools, especially for AI, ML, or data
• Empathy for practitioners and researchers in AI, ML, data engineering, NLP, or other quantitative work
• Eye for visual and interaction design with an emphasis on simplicity
• Enjoyment of engaging with users and the community daily
• Proficiency in Python, or willingness to learn
• Experience with AI engineering, including MCP and agents
• Experience with SQL, databases, and data engineering
• Experience working on open‑source projects

Base salary range: $165,000–$242,000, with additional discretionary bonus, equity, and a comprehensive benefits program.

• Medical, dental, and vision insurance – 100% paid by Core Weave
• Company‑paid Life Insurance
• Voluntary supplemental life insurance
• Short and long‑term disability insurance
• Flexible Spending Account
• Health Savings Account
• Tuition Reimbursement
• Employee Stock Purchase Program (ESPP)
• Mental Wellness Benefits through Spring Health
• Family‑forming support provided by Carrot
• Paid Parental Leave
• Flexible, full‑service childcare support with Kinside
• 401(k) with generous employer match
• Flexible PTO
• Catered lunch each day in our office and data center locations
• Casual work environment
• Work culture focused on innovative disruption

We prioritize a hybrid work environment. Remote work may be considered for candidates located more than 30 miles from an office, depending on role requirements. New hires will attend onboarding at a hub within their first month, and teams gather quarterly to support collaboration.

Core Weave is an equal‑opportunity employer committed to fostering an inclusive and supportive workplace. All qualified applicants 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. Under the Americans with Disabilities Act, Core Weave will provide reasonable accommodations for the hiring process unless undue hardship.

If accommodation is needed, please contact

This position requires access to export‑controlled information. To comply with U.S. Government export regulations, the applicant must be a U.S. person (citizen or permanent resident, refugee, asylee, or otherwise eligible). Eligible personnel may access the information without required export authorization, or obtain the necessary authorization from the U.S. government agency. Core Weave may decline to pursue an export licensing process for legitimate business reasons.