Principal Engineer (Backend / Platform)About Us
We are a Cambridge, MAโbased rapidly scaling Generative AI startup.
Our platform enables thousands of AI Agents to โthinkโ and cooperate for hours to generate high-quality code at scale for enterprises. We specialize in working with large-scale enterprise codebases and executing large-scale changes. The platform delivers everything AI can produce in a precise manner โ roughly 80% of any roadmap or large-scale feature addition โ supplemented by a human engineering guide to complete the remaining 20% needed for production.
We deliver 3xโ5x engineering velocity improvements to our enterprise customers. With over 27 patents and counting, we are actively hiring senior technologists in Cambridge, MA who are passionate about building AI that leverages โSystem 2 Thinkingโ to solve problems at inference.
We are rapidly growing.
Location
One Kendall Square, Cambridge MA 02139 (In-person role)
The Role
We are hiring a Principal Engineer to take full, hands-on ownership of our 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 โ 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 the platform using the platform itself, holding it 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 (GCP mandatory)
Expert-level Kubernetes experience 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
NoSQL: MongoDB, Cassandra, DynamoDB, or similar
Graph databases (Neo4j) for modeling complex relationships
Vector databases and embeddings infrastructure for semantic search
AI / LLM Tooling
Experience building and operating LLM-powered systems in production
Designing and implementing LLM validation loops (evaluation, feedback, regression testing, failure analysis)
LangSmith or equivalent tooling for tracing and evaluation
Familiarity with models or vendors such as OpenAI or Anthropic is a plus
Frontend & Full-Stack Competency
Strong understanding of frontend frameworks and architecture
Ability to evaluate and contribute to frontend technical decisions
Proven ability to debug, design, and ship across frontend, backend, infrastructure, and AI layers
Enterprise Systems
Ways to Stand Out
Prior experience operating at Principal Engineer / Staff+ scope
Clear ownership of complex systems built and supported in production
Hands-on ownership of LLM validation loops in real environments
Experience combining graph, vector, and relational data models
Proven ability to deliver outsized impact through the right features
Track record of self-direction and uncompromising quality
Youโll Getโฆ
Competitive salary and equity
Medical, dental, and vision insurance for you and your dependents
4% 401(k) match
Flexible vacation, sick days, and work-from-home days
Technology and learning allowance
The opportunity to reshape an entire industry
A beautiful office environment in a vibrant startup community
Unlimited snacks, coffee, espresso, and everything you need to perform at your best
Culture
We work hard, stay curious, and believe in a low-ego, high-output approach. The individual contributor is the most respected role in the company. We manage the work, not the people.
We are roughly 60 employees today and expect to double headcount over the next 6โ8 months. This is a high-growth company operating at high speed.
We move fast on two-way door decisions. A good decision today beats a perfect decision next week.
We believe in being everyday athletes โ prioritizing sleep, movement, and restorative habits to bring our best minds to work.