Senior Full Stack Engineer (AI Platforms)
Location: Remote, UK only
Job Type: Full-time
Industry: Artificial Intelligence / Software Development
About the Role
We are currently partnering with an exceptionally well-funded AI start-up that is building the next generation of proactive, AI-native personal productivity applications.
There are over 5 billion people using basic daily applications—email, notes, tasks, calendars—that were never built for the AI era. This team’s mission is to build proactive, AI-native applications for a global audience, eliminating the need for complex prompting. They are bringing intelligence directly into conversations, daily errands, personal organization, and complex workflows.
Their platform focuses on high reliability for long-running agentic workflows, persistent context, and real-world task completion—dramatically reducing model hallucinations through smart, stateful system design. With significant backing from premier investors, they are scaling a high-density engineering team to organize everyday life for millions.
As a Senior Full Stack Engineer, you will own product features end-to-end across both backend services and client interfaces. You will build high-throughput APIs, design responsive real-time UI components, integrate autonomous AI agents into user workflows, and optimize data persistence and query performance across complex, asynchronous applications.
Key Responsibilities
- End-to-End Engineering: Architect, build, and ship complete full-stack features from database schemas down to responsive client UIs.
- AI & Agent Workflows: Integrate multi-agent workflows, tool-calling frameworks, and streaming LLM outputs into real-time user interfaces.
- Real-Time Data Pipelines: Build and maintain scalable REST/GraphQL endpoints, WebSockets, and event streams for low-latency collaboration (live presence, typing indicators, state syncing).
- Performance & Scale: Profile and optimize API latency, client rendering, background jobs, and database queries under high concurrency.
- State & Persistence: Design robust schemas and caching layers (PostgreSQL, Redis, vector databases) capable of handling persistent context and long-running user sessions.
- Autonomous Execution: Partner directly with technical leaders to translate ambiguous requirements into clean, production-grade software shipped at rapid speed.
Qualifications
- Full-Stack Mastery: Strong commercial experience building production systems using TypeScript, Node.js / Python, and modern frontend frameworks (React, Next.js).
- Backend & API Design: Deep understanding of RESTful API design, background job processing (Celery, BullMQ), and WebSocket / Server-Sent Events (SSE) streaming.
- Database Experience: Hands-on expertise with relational databases (PostgreSQL) and key-value/NoSQL stores (Redis, DynamoDB).
- AI Ecosystem: Direct experience or strong familiarity integrating LLM APIs (OpenAI, Anthropic), vector embeddings, LangChain/LangGraph, or RAG architectures.
- Observability & Tooling: Familiarity with performance profiling, client rendering optimizations, and monitoring tools (Grafana, Prometheus, Datadog).
Tech Stack
- Languages: TypeScript, Node.js, Python
- Frontend: React, Next.js, Tailwind CSS
- Backend: FastAPI, Node.js, REST, WebSockets, Server-Sent Events (SSE)
- Databases: PostgreSQL, Redis, Vector Databases
- DevOps: Docker, Kubernetes, AWS/GCP, CI/CD
How They Work
The company operates as a small, world-class team that values high talent density, rapid iteration, and direct execution. They make decisions collectively, move at fast speeds, and strike a balance between shipping high-quality code and learning quickly. Joining this team requires bringing structure to ambiguity, exercising sharp engineering judgment, and executing independently.