Senior Full-Stack Engineer (TypeScript & LLM Integration) - £110K, Remote UK

JR United Kingdom; Watford; Remote; GBP 90,000 - 110,000; Full time

Job summary

A leading AI start-up is seeking several Senior Full-Stack Engineers to join their product team in Watford. You'll be working on innovative software powered by AI, focusing on web application development and AI integration using cutting-edge technologies like TypeScript and Next.js. This is a unique opportunity to shape the future of AI-driven applications with a talented team.

Qualifications

• Proven experience in a unified codebase combining application logic and AI components.
• Strong proficiency in building modern web applications with Next.js and TypeScript.
• Practical experience with AI models such as ChatGPT, including API integration.

Responsibilities

• Build and maintain web application features using TypeScript, React, Node + Next.js.
• Integrate and optimize commercially available LLMs via prompt engineering.
• Design and optimize the MySQL database.

Skills

TypeScript

AI Integration

Next.js

Prompt Engineering

tRPC

Prisma

LangChain

Job description

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Senior Full-Stack Engineer (TypeScript & LLM Integration) - £110K, Remote UK, watford, hertfordshire

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Client:

Oliver Bernard

Location:

watford, hertfordshire, United Kingdom

Job Category:

Other

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EU work permit required:

Yes

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Job Views:

12

Posted:

09.06.2025

Expiry Date:

24.07.2025

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Job Description:

A hugely exciting AI start-up is seeking several experienced Full-Stack Engineers to join a dynamic product team, focused on building innovative software powered by cutting-edge AI technologies.

This is a unique opportunity for a passionate developer to contribute to an ambitious product and work at the forefront of AI integration.

About the Role

The successful candidate will work within a unified codebase that powers both the B2B software platform and its custom AI capabilities. Responsibilities will span the full feature lifecycle, from design (including data structures) to AI integration, enhancing user experiences through advanced Large Language Models.

Key Responsibilities

• Build and maintain web application features using TypeScript, React, Node + Next.js
• Contribute to and maintain a monorepo that includes both the B2B SaaS platform and AI/LLM modules
• Integrate and optimize commercially available LLMs (e.g., OpenAI, Gemini) via prompt engineering and inference pipeline management
• Implement multi-step LLM workflows using orchestration frameworks such as LangChain.
• Design and optimize the MySQL database
• Develop and maintain type-safe RPC endpoints using tRPC and TypeScript to ensure smooth frontend-backend communication
• Rapidly onboard to a modern TypeScript stack to support high-velocity feature development

Required Qualifications

• Proven experience working in a unified codebase combining application logic and AI/LLM components
• Strong proficiency in building modern web applications with Next.js, tRPC, TypeScript, and Prisma
• Practical experience integrating with AI models such as ChatGPT or Gemini, including prompt engineering and API management
• Familiarity with tools like LangChain (or similar) to implement multi-step AI workflows
• A demonstrated ability to learn quickly and deliver functional features in a fast-paced environment

Preferred Qualifications

• Experience deploying and fine-tuning custom AI models
• Prior experience developing B2B software platforms with multi-user functionality