Senior Full Stack Engineer (Backend Focus)

Rapidly Expanding AI Startup

Remote (UK-based)

Competitive Salary + Strong Equity with potential early realisation (12–18 months)

We’re working with an early Series A, rapidly scaling AI startup building a next-generation platform that helps enterprises turn AI ambition into production-grade, measurable business outcomes.

The product enables teams to design, deploy, and operationalise AI agents in real-world environments with strong early traction already across enterprise customers.

This is a high-ownership engineering role, with a clear emphasis on backend systems, architecture, and scalable AI infrastructure, while still contributing across the full stack when needed.

Why this role stands out

✔️ Early Series A stage, strong funding, fast growth trajectory, product already in market.

✔️ Real enterprise traction, working systems already in production with global clients.

✔️ Backend ownership, core services, architecture, and system design responsibility.

✔️ AI-native product, building deeply with LLMs, agents, and streaming systems.

✔️ Small, elite engineering team, high autonomy, low ego, high trust environment.

✔️ High-impact equity, meaningful upside tied directly to company scale.

️ What you’ll be doing

• Own end-to-end product features, with a strong focus on backend systems and architecture.

• Design and build scalable Python services (FastAPI or similar) powering AI workflows.

• Build and operate AI-native systems – async processing, streaming pipelines, state-heavy workflows.

• Collaborate with Product, Design, and AI teams to ship production-grade features.

• Contribute to frontend development (TypeScript / React) where needed for full feature ownership.

• Drive engineering quality across testing, performance, observability, and reliability.

• Help shape technical direction and mentor other engineers in a high-trust environment.

⚙️ Tech environment

Backend (core focus):

• Python (FastAPI or similar).

• Async/concurrent systems, API design, distributed workflows.

Frontend:

TypeScript, React, Next.js.

Data:

• Postgres (schema design, performance tuning, migrations).

Auth & Security:

• OAuth / OIDC, JWT, RBAC / ABAC.

AI / Platform:

• LLM integrations and tool/function calling.

• Streaming architectures to frontend.

• Vector databases.

• Agent-based systems and state management.

✅ What we’re looking for

• Strong experience as a backend-leaning full stack engineer in production environments.

• Deep expertise in Python backend systems (FastAPI or similar).

• Strong TypeScript + React capability (able to ship end-to-end features).

• Experience building SaaS platforms with authentication and permissions.

• Exposure to AI-native development or LLM-powered systems.

• Strong product thinking and ability to work in ambiguous environments.

• Comfortable taking ownership of core backend architecture and services.

Why join

This is a chance to join an early Series A company at a pivotal scaling point, where engineering decisions directly shape product direction, architecture, and long-term success.

You’ll be joining a small, highly technical team building infrastructure for the next wave of enterprise AI adoption.