Senior Full Stack Engineer (Backend-Leaning)

Series A AI Startup, Rapid Expansion

Remote (UK-based)

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

A rapidly scaling AI startup is building infrastructure that helps enterprises turn AI ambition into real, measurable business value.

The platform enables teams to discover, assemble, and deploy production-grade AI agents with enterprise-grade control, observability, and reliability. The product is already in production with early enterprise customers and is now scaling quickly.

We’re looking for a Senior Full Stack Engineer (backend-leaning) to own critical services and help shape how AI-native systems are built at scale.

Why this role stands out

✔️ Early Series A stage with real enterprise traction in production.

✔️ High ownership over backend architecture and core product systems.

✔️ AI-native platform built around LLMs, agents, and streaming workflows.

✔️ Small, high-trust engineering team with strong technical bar.

✔️ End-to-end product ownership across backend and frontend.

✔️ Meaningful equity with strong upside potential.

️ What you’ll be doing

• Own end-to-end product features across backend, frontend, and infrastructure.

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

• Architect async systems, streaming pipelines, and state-heavy workflows.

• Build high-quality UX for AI-driven products (React / TypeScript / Next.js).

• Collaborate closely with Product, Design, and AI/ML teams.

• Improve reliability, observability, performance, and testing across systems.

• Influence technical direction and engineering standards.

• Mentor and support other engineers through reviews and pairing.

⚙️ Tech environment

Backend (core focus):

Python (FastAPI or similar), async/concurrent systems, distributed workflows, API design.

Frontend:

TypeScript, React, Next.js.

Data:

Postgres (schema design, migrations, performance tuning).

AI / Platform (nice to have):

• LLM integrations (tool/function calling).

• Streaming architectures to frontend.

• Vector databases.

• Agent-based systems & state management.

Auth & Security:

OAuth / OIDC, JWT, RBAC / ABAC

✅ What we’re looking for

• Senior-level experience shipping production web applications.

• Strong Python backend experience (FastAPI or similar).

• Strong TypeScript + React capability.

• Experience building SaaS platforms with authentication and permissions.

• Exposure to AI/LLM-based systems (advantageous but not essential).

• Strong database fundamentals (Postgres).

• Product mindset and comfort with ambiguity.

• Strong communicator across engineering and product teams.

Why join

This is an opportunity to join at a pivotal scaling stage in a company building infrastructure for enterprise AI adoption.

You’ll have significant ownership over core systems, real influence on product direction, and the chance to shape a category-defining platform from an early stage.

The team is small, technical, and fast-moving, with a strong focus on craft and impact.