Senior Software Engineer I

CoreWeave•Philadelphia, NJ

11d•Onsite

About The Position

Applications Engineering, part of CoreWeave’s Data Infrastructure organization, builds the software CoreWeave uses to plan and operate its own infrastructure business. Some of that is UNION, our data platform, where anyone in the company can query the lakehouse in plain language and stand up their own dashboards, applications, and agents. The rest is the applications behind decisions like which data centers get which hardware and when, for a company adding gigawatts of capacity a year. Engineering, finance, supply chain, and data center operations all depend on what we ship. You will build full-stack applications, and features in UNION itself, and own all of it in production, from the interface down to the data model. Our stack is TypeScript with React and Next.js, Python services running on Kubernetes, and Postgres alongside the lakehouse. We care more that you have built and run this kind of software than which frameworks you built it in. A good share of the work is AI-facing, meaning natural language interfaces and agents that operate on governed data, plus the evaluation work that tells you whether they are any good. Owning a product area here means you sit with the people who run the process and work out with them what the software should do. You are also the one who answers for it when it breaks. Most of these processes have never been written down anywhere, so a fair amount of the job is working out what to build before you build it.

Requirements

5+ years building and operating production software, including both backend services and modern web frontends.
Strong Python and TypeScript.
Real experience in React, Next.js, or a comparable modern framework.
Experience designing and running HTTP APIs that other services depend on, including timeouts, retries, and keeping writes correct when a call fails partway through.
Strong SQL and relational data modeling, including schemas that had to be changed after they were already live.
Experience shipping LLM-backed features to production, including how to measure whether their output was correct.
Hands-on experience with containers and deployment tooling such as Docker, Helm, and Kubernetes, and with operating your own services.
Experience wiring applications up to data platforms and analytical databases such as Spark, Kafka, StarRocks, or Snowflake.
Experience with CI/CD, automated testing, observability, and on-call for the software you own.
Experience working directly with non-engineers on problems nobody had specified yet, and shipping software they adopted.

Nice To Haves

Experience building AI-native applications such as text-to-SQL interfaces, copilots, agents, or automated insight generation.
Experience with agent frameworks such as LangGraph, and with the tracing and evaluation tooling around them.
Experience designing and running distributed systems in cloud-native environments such as Kubernetes.
Familiarity with open table formats such as Iceberg, Delta, or Hudi, and with query engines such as StarRocks, Snowflake, or BigQuery.
Experience building internal platforms or tools that other teams used to answer their own questions.
Background in an operationally heavy domain such as capacity planning, supply chain, or finance.

Responsibilities

Build full-stack applications and features in UNION.
Own applications and features in production, from the interface down to the data model.
Develop AI-facing features, including natural language interfaces and agents that operate on governed data.
Conduct evaluation work to assess the quality of AI-generated output.
Collaborate with process owners to define software requirements.
Troubleshoot and resolve issues when software breaks.
Determine what to build before development begins, as many processes are not documented.