Principal Engineer (Backend / Platform)

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.

Location: 1 Kendall Square, Cambridge, MA 02139 (In-person)
Compensation: $300,000 – $500,000 (base + equity, tailored to demonstrated Principal-level experience, scope of ownership, and production impact)

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. 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 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

Required Experience

• Prior experience operating at Principal Engineer / Staff+ scope in a highly technical environment
• Deep, hands-on expertise across most of the following:
• • Backend: Python (primary), backend frameworks and microservices, RPC-based services (REST, gRPC), Node.js/JavaScript
  • Cloud & Infrastructure: Expertise across at least two of AWS, GCP, and Azure (GCP mandatory); expert-level Kubernetes; Terraform; production monitoring and reliability tooling
  • Databases & Data Systems: SQL (PostgreSQL, MySQL) and NoSQL (MongoDB, Cassandra, DynamoDB); graph databases (Neo4j); vector databases and embeddings infrastructure
  • AI / LLM Tooling: Building and operating LLM-powered systems in production; designing LLM validation loops; LangSmith or equivalent tracing and evaluation tooling
  • Frontend & Full-Stack: Strong understanding of frontend frameworks; ability to debug, design, and ship across the full stack
• Core understanding of how large-scale enterprise systems are designed, integrated, deployed, and operated

What Makes You Stand Out

• Prior experience operating at Principal Engineer / Staff+ scope at a highly technical company
• Deep understanding of enterprise software systems built and evolved at scale, including tradeoffs around reliability, change management, and long-term maintainability
• Clear ownership of complex systems 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

What Makes This Role Different

Unlike typical senior engineering roles, you'll be:

• The most senior individual contributor at the company — your ownership and judgment set the standard
• Working at the frontier of AI-powered enterprise software development, with over 27 patents and counting
• Building and improving Blitzy using Blitzy itself, holding the platform to real-world production standards
• Making durable technical decisions with direct company-wide impact
• Operating with a high degree of autonomy in a fast-moving, low-ego, high-output environment

Our Culture

Who we are:

Led by two pioneering co-founders we are one of the fastest growing companies in the U.S., creating our own category of enterprise autonomous software development. We automate thousands of hours of software development for our customers, which includes strong representation within the Fortune 500.

How we work:

We move Blitzy Fast: Time is both our company's and our clients' most precious asset. We move quickly and decisively to innovate internally and deliver exceptional software externally.

Championship Mindset: We operate like a professional sports team. We win as a team by holding ourselves and each other to high standards, collaborating in-person, and remaining focused on the mission.

Passion for Invention: We're pushing the frontier of what's possible, requiring constant innovation and iteration.

We Work for the Customer: We focus on delivering outsized value to the customers we work with and expanding those relationships into deep, meaningful partnerships.

We believe in being 'everyday athletes'—taking care of ourselves so we can bring our best minds to work. We promote great sleep, movement, and restorative activities for optimal mental performance. It makes for a happier and more productive team.

Blitzy is an equal opportunity employer committed to building a diverse and inclusive team. We believe different perspectives make us stronger.