Principal Backend Engineer (Applied AI)

About the CompanyOur client is a venture-backed applied AI company rebuilding a $500 billion industry that has never had a real software platform underneath it: civil, structural and MEP engineering. Instead of selling software to engineering firms, they acquire them, keep their people and their names, and install their own technology and engineers inside. They are backed by a top-tier venture firm with significant capital set aside for acquisitions with this being highest-priority engineering hire in the company.

Find out more about this role by reading the information below, then apply to be considered.
About the RoleThis is a hands-on Principal engineer seat: you’ll design and build the backend services and product features that bring AI into how engineering firms actually work. That means taking messy, real-world inputs like drawings, specifications, calculations and correspondence, and turning them into reliable production systems built on LLMs and agentic workflows. You’ll own systems from design through production, set the architecture the rest of the team builds on, and work directly with the CTO on technical direction. This is an individual contributor role for someone who still writes code every week.
What You Will DoDesign, build and own backend services and APIs, from new product features to core platform servicesBuild production systems that use LLMs, agents and RAG to parse documents, automate workflows and act on unstructured dataDesign agentic workflows that are reliable in production: evaluation, guardrails, retries, failure handling and human reviewLead the architecture of event-driven and asynchronous systems, including queues, background processing and integrations with legacy softwareShape multi-tenant architecture so each new firm is faster to onboard than the lastOwn reliability for what you ship, including observability, incident response and performanceUse AI coding tools like Claude every day to move faster, and help set how the team uses themPartner with the CTO and forward deployed engineers on long-term architecture and engineering standards
What We Are Looking For8+ years building backend or distributed systems in productionProven ownership of services with real uptime, latency and scale requirements, with clear stories about what you built, the tradeoffs and what brokeExperience designing and evolving APIs, services and event-driven systemsHands-on experience shipping LLM-powered or agentic features to real users, not just prototypesStrong in at least one backend language. Kotlin and Python are used today, but architecture judgment matters more than stack. xzbcwsv Experience at a venture-backed startup or a company with a comparably high technical barComfort with ambiguity, strong communication, and opinions you’ll change when you hear a better argument
Nice to HaveFounding or early engineer experienceDocument processing, OCR or integrations with entrenched enterprise softwareInfrastructure ownership on AWS with infrastructure as codeBackground in civil, structural or MEP engineering, construction tech or CAD/BIM
This Role Is Not a Fit IfYour AI experience is mostly research, model training or prompt engineering, without production backend depthYour recent work is mainly DevOps, SRE or cloud operationsYou’ve moved into management or architecture and no longer write codeYou need a remote or hybrid role
Compensation and Logistics$200,000 to $300,000 base, depending on experienceFounding-stage equity with dilution protection through the Series ARelocation support and full healthcareTitle is flexible across Senior, Staff, Principal or Founding EngineerOn-site in New York City five days a week, with light, flexible travel to acquired firms
Why This Role MattersYou’ll be the CTO’s right hand, building the platform that an entire industry’s transformation runs on, at the stage where your decisions become the foundation.