Senior Backend Engineer (AI Platform)

The role

You will build services for LLM infrastructure, including the LLM gateway, retrieval and knowledge services, and an async framework. You will design authorization and build evaluation harnesses for retrieval tuning.

What you will do

• Own the LLM gateway: routing, metering, budgets, guardrail composition, and provider/backend adapters
• Manage the retrieval and knowledge service: connectors, chunking, hybrid search and reranking, grounded answers, and the MCP surface
• Build the eval harness that turns retrieval tuning from judgment into evidence
• Own the async framework, its public API, rate-limit algorithms, and admin tooling
• Design authorization across the whole surface: token hierarchies, capability grammars, and per-tenant isolation
• Own definition of done on everything shipped: evals, traces, cost accounting, and the dashboard

Required qualifications

• 5+ years of deep, production async Python
• Postgres as infrastructure experience with real distributed-systems experience
• Experience shipping API surfaces other engineers build on
• Depth in at least one of LLM gateway concern or retrieval engineering, with credibility on the other
• A cost accounting and evals first mindset
• Production depth in some modern stack
• Practical familiarity with Python 3.12+, asyncpg/SQLAlchemy, Postgres (incl. pgvector), and Redis/Dragonfly with Lua
• Exposure to OpenTelemetry, SSE/streaming lifecycles, OpenAI/Anthropic provider APIs, job frameworks, rate-limit algorithms, and integer-cents money handling

Nice to have

• Past work in energy, real estate, utilities, climate or related fields
• Experience in both startup and enterprise environments

Benefits

• Competitive early-stage startup compensation
• Bonus eligibility
• Health insurance with meaningful coverage for dependents
• Flexible paid time off
• Equity

Before you apply

• Must be willing to travel to Seattle area for final interview and travel 2x/year for company summits
• Applicants must be currently authorized to work in the United States on a full-time basis
• We are unable to sponsor or take over sponsorship of employment visas at this time
• Please only apply to a maximum of 2 roles at a time; applicants who apply to more than 2 roles within a 6 month period will automatically be disqualified

About the company

AZX is a public benefit corporation founded in 2024 that specializes in physics-informed ML and enterprise AI solutions for climate and sustainability challenges. The company is profitable and works with leaders in real estate, energy, logistics, and utilities.