Senior TypeScript Backend Engineer – Remote, AI-Powered

Darwin Recruitment; Greater London; Remote; GBP 94,000 - 140,000; Full time

Job summary

Darwin Recruitment is seeking a freelance Senior TypeScript Backend Engineer to join a product development team for a 3-month contract, with high extension potential. The role is remote across Europe, 100% remote, working on backend services and AI-powered features.

You will design, build and iterate features end to end using Node.js (NestJS/Express/Fastify), with emphasis on API design and scalable architectures.

Qualifications

• Senior-level, hands-on TypeScript expertise on the backend (Node.js with NestJS, Express or Fastify)
• Proven delivery of production-grade applications from concept through to release
• Strong API design and system integration experience
• Ability to own features independently with minimal oversight
• Working knowledge of LLMs, agentic AI and AI-powered applications
• Familiarity with AI agent frameworks, orchestration patterns and tool integrations (advantageous)
• Background in fast-paced, experimental product environments (advantageous)

Responsibilities

• Design and implement backend features end-to-end with a focus on scalable services
• Collaborate on AI-powered capabilities and integrations with LLMs
• Own features from concept to release with minimal oversight

Skills

TypeScript backend

Node.js

NestJS/Express/Fastify

API design

LLMs / AI

AI agent frameworks

Job description

Darwin Recruitment is seeking a freelance Senior TypeScript Backend Engineer to join a product development team for a 3-month contract, with high extension potential. The role is remote across Europe, 100% remote, working on backend services and AI-powered features.

You will design, build and iterate features end to end using Node.js (NestJS/Express/Fastify), with emphasis on API design and scalable architectures.