Senior Engineer, Core API - W&B

CoreWeave•New York City, NY

2d•$165,000 - $242,000•Hybrid

About The Position

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. 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.

Requirements

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

Nice To Haves

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

Responsibilities

building and evolving the core backend systems and shared infrastructure that power our platform
define, maintain, and scale that foundation
own and improve internal schema and code generation tooling that ensures consistency and correctness across services
work on and extend our custom job scheduler, improving reliability, observability, and execution guarantees for distributed workloads
contribute to safely execute large-scale concurrent and distributed operations
defining and maintaining API standards across teams, ensuring performance, backward compatibility, and clear evolution strategies
collaborate closely with Product and various Engineering teams to design systems that are reliable, scalable, and maintainable over time