Principal Software Engineer

ABOUT BLITZY Blitzy is a Cambridge, MA based AI software development platform on a mission to revolutionize the software development life cycle by autonomously building custom software to unlock the next industrial revolution. We're transforming how enterprises build software, turning enterprise requirements into production-ready code with an agentic software development platform that can autonomously execute 80% of the quantum of software development work. We're backed by multiple tier 1 investors, and have proven success as founders of previous start-ups. THE ROLE We are hiring a Principal Engineer to take full, hands-on ownership of Blitzy's most critical production-grade systems and to deliver high-leverage features that materially improve customer outcomes and engineering velocity. This is the most senior individual contributor role at the company today. This is not a Senior-plus role, an architecture-only role, or a promotion-track role. We are looking for someone who has already operated at Principal / Staff+ scope in a highly technical environment and expects to spend their time writing, reviewing, and shipping production code. This role is 100% hands-on. Leverage comes from system ownership, execution quality, and durable technical decisions — not people management or process. WHAT SUCCESS LOOKS LIKE - You independently own mission-critical production systems end-to-end - You ship high-leverage features that materially improve reliability, performance, and customer value - You raise the technical bar through working code and outcomes, not reviews alone - You identify and resolve the hardest technical bottlenecks limiting quality or velocity - You make technical decisions with long-term impact and stand behind them in production - You are a self-directed learner requiring minimal supervision - You are dedicated to getting things done right without making technical compromises - You demonstrate strong technical expertise across the full stack: frontend, backend, infrastructure, and AI systems - You materially increase the effectiveness of the engineering organization through example and judgment AREAS OF OWNERSHIP - End-to-end ownership of production-grade backend systems used by enterprise customers - Correctness, scalability, performance, and operational reliability in real environments - Delivery and stewardship of high-impact features, not just incremental improvements - Building and improving Blitzy using Blitzy, holding the platform to real-world standards - Designing, operating, and evolving LLM validation loops to ensure correctness, consistency, and durability in production - Setting engineering quality and durability expectations across teams without direct reports CORE TECHNOLOGIES & REQUIRED EXPERIENCE This role demands strong, hands-on experience across the full technology stack. You should have deep expertise in most of the following: BACKEND - Python (primary language) - Backend frameworks and microservices architectures - RPC-based services (REST, gRPC) - Node.js and JavaScript (supporting languages) CLOUD & INFRASTRUCTURE - Expertise across at least two of AWS, GCP, and Azure, with GCP mandatory - Expert-level Kubernetes experience for container orchestration in production environments - Terraform for infrastructure as code - Production systems: monitoring, reliability, scalability, and operational tooling DATABASES & DATA SYSTEMS - Strong expertise across both SQL and NoSQL databases - - SQL: PostgreSQL, MySQL, or similar relational databases - NoSQL: MongoDB, Cassandra, DynamoDB, or similar 1. Graph databases (Neo4j) for modeling and searching complex relationships 2. Vector databases / embeddings infrastructure for semantic search and retrieval AI / LLM TOOLING - Experience building and operating LLM-powered systems in production - Designing and implementing LLM validation loops (evaluation, feedback, regression testing, and failure analysis) - LangSmith (or equivalent tooling) for tracing, evaluatio