Senior Full Stack Engineer - Agent Experience
Summary
Builds the UI and backend for an AI agent workspace where users interact with autonomous agents; ships features continuously in Next.js/React/TypeScript and Python/FastAPI.
Sydney · Full-time · On-site/hybrid
SuperNinja is an AI workforce that plans, writes code, runs research and ships real work for customers. You would own the surface where people meet that agent — the thread, the workspace, the moment a task becomes a deliverable. It is the highest-visibility slice of the product and it changes weekly.
What you'll do
Own end-to-end slices of the agent experience — UI, API and the backend services behind them, not just the frontend of someone else's endpoint.
Ship agent-facing features into production continuously and stay on them: reliability, latency, incidents, observability.
Turn ambiguous product bets into working software in days, then decide from usage data whether to double down or delete it.
Work directly with our AI and science engineers on how tools, context and streaming behave in the product.
What we're looking for
5+ years building and operating full-stack products in production.
Strong TypeScript/React (we run Next.js) and genuine backend depth in Python (FastAPI) — you can design a schema and debug a slow query, not only call an API.
Product instinct: you argue about the shape of the feature, not only the ticket.
Comfort with high change rates and incomplete specs. Agentic products do not hold still.
Stack: Next.js/React/TypeScript, Python/FastAPI, Postgres/Supabase, AWS (CDK, CloudFront, ECS, Lambda, Cognito), containerised agent sandboxes.