Senior Software Engineer, Query

CircleCI

20h•$165,000 - $255,000

About The Position

The Senior Software Engineer on CircleCI’s Query team builds and operates the data platform that makes pipeline, job, and test history available for product features and customer-facing APIs. The team extracts product data from transactional services and stores it in systems designed for historical and analytical workloads, with the goal of making data storage straightforward for other teams and historical queries fast and dependable at growing scale. The role owns and hardens a ClickHouse-based storage layer, designs schemas for current and emerging access patterns, and improves ingestion and query performance. It also designs and owns ingestion from event streams and durable workflows built on Temporal, ensuring reliable data delivery without slowing the services that produce it. The engineer will help make the platform the default path for historical queries, with indexing, caching, and tiered storage to support performance and ease of use. The position involves setting technical direction through design discussions and architecture decisions, helping choose data domains to migrate, and championing observability with tools such as Honeycomb, Datadog, and Rollbar. The engineer is expected to take ambiguous data problems from design to production, support teammates through reviews and mentoring, and address underlying causes of problems as well as immediate issues. CircleCI describes its engineering approach as AI-native, with AI tools used as a default part of how work is approached and solved.

Requirements

At least 5 years of experience building and operating production backend systems.
Hands-on experience building or owning data-intensive systems, such as ingestion pipelines, event-driven architectures, or analytical and time-series datastores.
Understanding of tradeoffs between transactional and analytical storage.
Experience designing schemas and tuning queries for high-volume workloads.
Strong Go skills, or strong skills in a comparable language and willingness to work in Go, including interface design, data modeling, service integration, and concurrency.
Understanding of distributed systems concepts including delivery guarantees, idempotency, backpressure, and failure recovery.
Experience leading the design of complex systems and making deliberate technical tradeoffs.
Production experience treating latency, reliability, and correctness as design concerns.
Daily use of AI tools and ability to discuss what has been built with them, how they changed the candidate’s approach, and where they fall short.

Nice To Haves

Experience with ClickHouse or another columnar database.
Familiarity with React and TypeScript.

Responsibilities

Own and harden the ClickHouse-based storage layer.
Design schemas for known and emerging data access patterns and tune ingestion and query performance for production-scale workloads.
Design and own data ingestion from event streams and durable workflows built on Temporal.
Ensure data arrives reliably, remains queryable while in transit, and does not slow the critical path of source services.
Evolve the platform into the default path for historical queries and make historical data easy for product teams and customers to access.
Build indexing, caching, and tiered storage to maintain performance.
Lead complex design discussions, document architecture decisions, make technical decisions, and help determine which data domains to migrate.
Use Honeycomb, Datadog, and Rollbar to monitor ingestion lag, query latency, and data correctness.
Take ambiguous data problems from design through production and help teammates move faster.
Investigate why problems occurred, resolve immediate issues, and address underlying team practices, processes, or systems.
Raise engineering quality through code reviews, mentoring, and direct feedback.
Use AI tools as a core part of engineering work and build AI-natively.