Senior Engineer, Core API - W&B

Core Weave is The Essential Cloud for AI. Built for pioneers by pioneers, Core Weave 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, Core Weave combines superior infrastructure performance with deep technical expertise to accelerate breakthroughs and turn compute into capability.

Founded in 2017, Core Weave became a publicly traded company (Nasdaq: CRWV) in March 2025. Learn more at

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 Core Weave. 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…