Principal Software Engineer

About this role

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

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- 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, evaluation, and debugging

- Familiarity with specific models or vendors (e.g., OpenAI, Anthropic) is a plus

FRONTEND & FULL-STACK COMPETENCY

- Strong understanding of frontend frameworks and architecture

- Ability to evaluate and contribute to frontend technical decisions

- Demonstrated technical expertise across the full stack — you can debug, design, and ship across frontend, backend, infrastructure, and AI layers

ENTERPRISE SYSTEMS

- Core understanding of how large-scale enterprise systems are designed, integrated, deployed, and operated

- Experience working within — or modernizing — complex, long-lived production environments

WAYS TO STAND OUT

- Prior experience operating at Principal Engineer / Staff+ scope at a highly technical company

- Deep understanding of how enterprise software systems are built and evolved at scale, including tradeoffs around reliability, change management, and long-term maintainability

- Clear ownership of complex systems that you designed, built, and supported in production

- Hands-on ownership of LLM validation loops used to ensure correctness and durability in real environments

- Experience designing systems that combine graph, vector, and traditional data models to support reasoning over complex domains

- Proven ability to deliver outsized impact through the right features, not just more code

- Track record of being a self-learner who requires minimal supervision and gets things done without compromising on quality

COMPENSATION

Total compensation: $300,000 - $500,000

This includes a mix of competitive base salary and equity, tailored to demonstrated Principal-level experience, scope of ownership, and production impact.

YOU'LL GET…

- Competitive salary and equity

- Paid medical, dental, and vision insurance for you and your dependents

- 4% 401(k) match

- Flexible vacation days, sick days, and work-from-home…