Principal Software Engineer

Blitzy; Cambridge (MA); On-site; USD 300,000 - 500,000; Full time

Benefits offered by this job

Competitive salary and equity

Paid medical, dental, and vision insurance

Flexible vacation days and work-from-home days

Job summary

Blitzy is hiring a Principal Engineer based in Cambridge, Massachusetts. This role demands full ownership of critical production systems, focusing on delivering impactful features that enhance customer outcomes and engineering velocity.

The successful candidate will operate at a high level of technical expertise, demonstrating strong skills across the full stack while maintaining hands-on involvement in production code. Join us in reshaping software creation with a competitive compensation package.

Qualifications

• 5+ years of experience in a highly technical environment is required.
• Demonstrated ability to ship high-leverage features.
• Experience operating within complex, long-lived production environments.

Responsibilities

• Independently own mission-critical production systems end-to-end.
• Ship high-leverage features improving reliability and performance.
• Make long-term technical decisions and stand behind them.

Skills

Strong technical expertise across the full stack

Backend frameworks and microservices architectures

Expertise across at least two of AWS, GCP, and Azure

Expert-level Kubernetes experience

Strong understanding of frontend frameworks

Experience building and operating LLM-powered systems

Education

Experience operating at Principal Engineer / Staff+ scope

Tools

Python

Node.js

Terraform

Job description

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

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, 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 days

• Technology (hardware, software, reading materials, etc.) equipment and/or allowance

• The opportunity to re‑shape an entire industry and create a platform that changes the future of software creation

• A beautiful office environment with adjacent offices shared by other startups — an energizing community

• Unlimited snacks, fizzy water, coffee, espresso, and whatever else you need to perform at your best