AI Engineer, Core

We are looking for an AI Engineer (Core) with 5–10 years of experience to build the foundational infrastructure behind Build's agentic AI platform. You'll be a backend/infra-focused engineer who thrives on high ownership, sharp technical opinions, and the challenge of designing production-grade systems for high-stakes AI workflows. This is a rare opportunity to join a 4-person engineering team and shape the entire technical foundation of a vertical AI company working with some of the biggest names in institutional real estate.

What will you be doing?

• Build and evolve the core agent runtime — tool orchestration, workflow state, retries, fallbacks, and resumability for long-running agents
• Design and maintain retrieval and context systems that help agents reason over geospatial, financial, and document data
• Own observability, monitoring, alerting, and CI/CD pipelines for production AI systems
• Work with distributed systems, Postgres, columnar DBs, and queue systems (e.g. Kafka) to ensure reliability at scale
• Contribute to eval infrastructure — replaying traces, catching regressions, and measuring agent quality in production

Key Requirements

• Deep backend/infra experience — distributed systems, databases (Postgres, columnar DBs), observability, and CI/CD — with strong opinions you can defend
• Proficient in Python (primary), Go, or Rust; can articulate trade-offs between languages clearly
• Experience with AWS (Lambda, ECS, etc.), Kafka or similar queue systems, and production-grade backend architecture
• High agency and ownership mindset — comfortable with broad, ambiguous scope and delivering without heavy process