Senior Software Engineer, Query

CircleCI is hiring a Senior Software Engineer for its Query team. The role builds and operates data storage, ingestion pipelines, and query services that provide reliable historical data to CircleCI product teams and customers.

Responsibilities:

• Build AI-natively. AI is how we work. It's not a productivity layer on top of engineering, but the default starting point for how problems get approached and solved
• Shape how we store data at scale. Own and harden our ClickHouse-based storage layer. Design schemas for known and emerging access patterns, and tune ingestion and query performance to support production-scale data
• Build the pipelines that move our data. Design and own ingestion from event streams and durable workflows built on Temporal. Data should arrive reliably, stay queryable while it's in transit, and never slow down the critical path of the services that produce it
• Serve data to the product and to customers. Evolve our platform into the default path for historical queries. Make getting historical data easy, not a bottleneck. Teams should be able to get what they need quickly and with minimal hand-holding, while Query keeps enough visibility into how the data is used to optimize ingestion and reads across every consumer. Build in the indexing, caching, and tiered storage required to keep it performant
• Set technical direction. When the problem is complex or the answer isn't obvious, you lead the design discussion, write up the architecture decision, and make the call. You help decide which data domain we migrate next and how
• Champion observability. Use Honeycomb, Datadog, and Rollbar to understand ingestion lag, query latency, and data correctness. For a data platform, operational data drives stability, not just incident response
• Keep things moving. You take ambiguous data problems from design to production quickly, and you help the people around you move faster too
• You don't just patch problems, you ask why they happened. You'll fix the immediate issue, then solve the underlying team practice, process, or system that let it through

Requirements:

• You use AI tools daily and can speak to what you've built, where they changed your approach, and where they fall short
• You've built or owned data-intensive systems such as ingestion pipelines, event-driven architectures, or analytical and time-series datastores
• You understand the tradeoffs between transactional and analytical storage, and you've designed schemas and tuned queries for high-volume workloads
• You're strong in Go, or strong in a comparable language and eager to work in Go: interface design, data modeling, service integration, and concurrency
• You understand delivery guarantees, idempotency, backpressure, and failure recovery
• You know when to rely on a framework's reliability guarantees rather than building your own
• You've led the design of complex systems and made tradeoffs deliberately
• You leave foundations others can build on
• You raise the quality bar through reviews, mentoring, and direct feedback, not just through the code you write
• 5+ years building and operating production backend systems
• Your work has served real users, and you've treated latency, reliability, and correctness as design concerns
• Experience with ClickHouse or another columnar database is a strong plus
• Familiarity with React and TypeScript is a plus, since you'll occasionally work on the product surfaces that display this data