Senior Full Stack Engineer - React, Typescript, Node, Serverless AWS, Claude - Global B2B SaaS at Smart-Sourcer, United Kingdom (Only), 9 Months, £600-£800 per day

Senior Full Stack Engineer - React, Typescript, Node, Serverless AWS, Claude - Global B2B SaaS

? £600-£800 per day ? Outside IR35 ? 9 months ? 100% remote

We're hiring a Senior Full Stack Engineer to architect, build and ship complex, high-performance features for a greenfield, enterprise-scale B2B SaaS platform. This is a hands-on, forward-deployed role where you'll work directly with clients and own outcomes end-to-end across the stack.

You'll be:

• Architecting and delivering high-performance Full Stack TypeScript applications across React and Node, operating within a large, distributed, enterprise SaaS ecosystem.
• Working directly with clients to elicit real workflow requirements, prototype in-session, and translate messy real-world problems into production grade software.
• Driving product thinking, scoping, trade-offs and delivery, you won't be waiting for a PO to tell you what to build.
• Using Claude Code and advanced agentic workflows to augment development, orchestrating multi-agent patterns, managing context, running parallel workstreams and embedding AI-native engineering into everyday delivery.
• Crafting beautiful, interactive UX from low-fidelity inputs using a modern design system, producing polished UI without waiting for perfect Figma.
• Influencing architecture, patterns, state management, API design and performance across a large-scale platform.
• Raising the engineering bar through pairing, PR review, testing discipline, accessibility, performance and secure-by-default coding.

You'll bring:

• Deep expertise in TypeScript, React, Node, modern FE architecture, and state management (Redux Toolkit, Zustand, TanStack Query, Apollo).
• Strong Back End fundamentals: serverless AWS, REST, GraphQL, relational NoSQL modelling.
• Experience in high volume, high transaction SaaS systems
• Genuine client-facing confidence, discovery sessions, whiteboard-to-code, pushing back on bad requirements.
• A pragmatic, outcome-oriented mindset with strong product instincts.

. ? £600-£800 per day ? Outside IR35 ? 9 months ? 100% remote