Full-Stack Engineer

Frontier puts AI in front of operations teams — surfacing execution drift, risk exposure, and approved next actions through a product people trust and want to use. The product engineering team in Sofia builds the application layer that makes this real.

The Role

You build the products that put our AI in front of customers — the application layer around the agents, models, and pipelines the AI organization produces. You work end-to-end: polished, responsive front-ends and the backend services and APIs behind them, integrated both with our AI capabilities and with SubcontractorHub's core platform.

You care about UX and about the unglamorous parts — auth, multi-tenancy, error states, latency, performance — that make an AI feature feel trustworthy in production rather than like a demo.

Tech Stack

• Frontend: React, TypeScript, modern CSS
• Backend: Python, FastAPI, Pydantic
• APIs: REST, streaming responses
• Database & cache: PostgreSQL, MariaDB, Valkey
• Integration: LangGraph / FastAPI AI services
• Cloud & observability: AWS (ECS Fargate), Sentry, Datadog

What We're Looking For

• 4+ years building and shipping full-stack web applications in production.
• Frontend — Strong with React and TypeScript, with real care for UX.
• Backend — Comfortable building APIs and services in Python with FastAPI.
• Databases — Solid relational SQL (PostgreSQL, MariaDB), schema design, and query performance.
• AI-product sensibility — Experience integrating LLM or ML features into applications — streaming output, handling latency and failure, and designing for non-deterministic responses — is a strong advantage.
• Multi-tenant SaaS realities — Auth, tenancy isolation, rate limiting, and observability.
• Communication — Clear written communication across PRs, proposals, and technical notes.