Senior Software Engineer, Core API - Weights & Biases

Weights & Biases; Sunnyvale (CA); On-site; USD 120,000 - 150,000; Full time

Benefits offered by this job

Medical, dental, and vision insurance – 100% paid for

401(k) with a generous employer match

Flexible PTO

Catered lunch each day

Job summary

Weights & Biases seeks a Backend Engineer to enhance core systems that power the platform at CoreWeave. You'll focus on evolving backend infrastructure, improving operational efficiency, and defining API standards. Ideal candidates have 5+ years of relevant experience.

This role offers opportunities to influence how systems are built and managed at scale, fostering an environment of collaboration and innovation.

Qualifications

• 5+ years of backend engineering experience building and operating production systems.
• Proven experience designing and maintaining distributed systems at scale.
• Strong proficiency in Go, Python, or a comparable backend systems language.

Responsibilities

• Build and evolve core backend systems and shared infrastructure.
• Improve internal schema and code generation tooling.
• Define and maintain API standards to ensure performance.

Skills

Backend engineering experience

Designing and maintaining distributed systems

Designing APIs (REST, GraphQL, gRPC)

Proficiency in Go or Python

Implementing concurrency patterns

Optimizing system performance

Job description

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

You will be responsible for building and evolving the core backend systems and shared infrastructure that power our platform. A significant portion of backend logic is shared across services, and this role will help define, maintain, and scale that foundation.

You will own and improve internal schema and code generation tooling that ensures consistency and correctness across services. You will work on and extend our custom job scheduler, improving reliability, observability, and execution guarantees for distributed workloads. You will contribute to safely execute large-scale concurrent and distributed operations.

You will play a key role in defining and maintaining API standards across teams, ensuring performance, backward compatibility, and clear evolution strategies. You will collaborate closely with Product and various Engineering teams to design systems that are reliable, scalable, and maintainable over time.

About The Role

The Core Systems team is responsible for the foundational backend infrastructure that powers Weights & Biases within CoreWeave. Much of the platform’s critical logic is shared across services, and this role sits at the center of that foundation. You will work on the systems that other engineers build upon — from execution frameworks and schedulers to schema tooling and API standards.

This is a high‑leverage role focused on durability, scalability, and long‑term maintainability. The systems you design and evolve will directly impact reliability, developer velocity, and the ability of the platform to scale with growing workloads. You’ll collaborate across teams to ensure that shared backend abstractions remain clean, performant, and consistent as we continue to expand our adoption of technologies like GraphQL and gRPC.

If you enjoy owning deep technical infrastructure, shaping engineering standards, and building systems that other engineers depend on every day, this role offers meaningful scope and impact.

Who You Are

• 5+ years of backend engineering experience building and operating production systems.
• Proven experience designing and maintaining distributed systems at scale.
• Hands‑on experience designing and evolving APIs (REST, GraphQL, and/or gRPC).
• Strong proficiency in Go, Python, or a comparable backend systems language.
• Experience implementing concurrency and parallelism patterns in production systems.
• Demonstrated ownership of shared infrastructure, internal platforms, or developer tooling used by multiple teams.
• Experience diagnosing and optimizing system performance, including CPU, memory, I/O, and network bottlenecks.

Preferred

• Familiarity with schema management, code generation tools, or interface definition systems (e.g., protobuf, OpenAPI, GraphQL schemas).
• Experience building or operating custom job schedulers, workflow engines, or execution frameworks.
• Experience defining cross‑team API standards and governance models.
• Background in high‑scale data or ML infrastructure systems.
• Experience improving reliability through observability, metrics, and SLO‑driven development practices.

Why Us?

We work hard, have fun, and move fast! We’re in an exciting stage of hyper‑growth that you will not want to miss out on. We’re not afraid of a little chaos, and we’re constantly learning. Our team cares deeply about how we build our product and how we work together, which is represented through our core values:

• Be Curious at Your Core
• Act Like an Owner
• Empower Employees
• Deliver Best‑in‑Class Client Experiences
• Achieve More Together

We support and encourage an entrepreneurial outlook and independent thinking. We foster an environment that encourages collaboration and provides the opportunity to develop innovative solutions to complex problems. As we get set for takeoff, the growth opportunities within the organization are constantly expanding. You will be surrounded by some of the best talent in the industry, who will want to learn from you, too. Come join us!

What We Offer

In addition to a competitive salary, we offer a variety of benefits to support your needs. The benefits below reflect our US‑based offerings; for roles in other locations, benefits vary and are shared during the hiring process.

• Medical, dental, and vision insurance – 100% paid for by CoreWeave
• Company‑paid Life Insurance
• Voluntary supplemental life insurance
• Short and long‑term disability insurance
• Flexible Spending Account
• Health Savings Account
• Tuition Reimbursement
• Ability to Participate in 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 a generous employer match
• Flexible PTO
• Catered lunch each day in our office and data center locations
• A casual work environment
• A work culture focused on innovative disruption

California Applicants

California Consumer Privacy Act

Equal Opportunity & Accommodations

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.

As part of this commitment and consistent with the Americans with Disabilities Act (ADA), CoreWeave will ensure that qualified applicants and candidates with disabilities are provided reasonable accommodations for the hiring process, unless such accommodation would cause an undue hardship. If reasonable accommodation is needed, please contact: [e-mail].

Export Control Compliance

This position requires access to export controlled information. To conform to U.S. Government export regulations applicable to that information, applicant must either be (A) a U.S. person, defined as a (i) U.S. citizen or national, (ii) U.S. lawful permanent resident (green card holder), (iii) refugee under 8 U.S.C. 1157, or (iv) asylee under 8 U.S.C. 1158, or (B) eligible to access the export controlled information without a required export authorization, or (C) eligible and reasonably likely to obtain the required export authorization from the applicable U.S. government agency. CoreWeave may, for legitimate business reasons, decline to pursue any export licensing process.

• 1157, or (iv) asylee under 8 U.S.C. 1158, (B) eligible to access the export controlled information without a required export authorization, or (C) eligible and reasonably likely to obtain the required export authorization from the applicable U.S. government agency.
• 1158, (B) eligible to access the export controlled information without a required export authorization, or (C) eligible and reasonably likely to obtain the required export authorization from the applicable U.S. government agency.