Senior Full-Stack Engineer (Python + Next.js)

Electric Twin Ltd; City Of London; On-site; GBP 65,000 - 85,000; Full time

Job summary

A forward-thinking tech startup in London seeks a Senior Full-Stack Engineer to develop next-generation applied AI tools. You will work with Python, SQL, and Next.js, collaborating directly with senior leadership. The ideal candidate has over 5 years of production software experience, great coding habits, and a passion for AI applications. Join a dynamic team where your contributions make a real impact.

Benefits

Fast-paced development with weekly shipping

Opportunity to impact product direction

Collaboration with experienced team members

Qualifications

• 5+ years' experience building production software, exceptional 4+ years considered.
• Strong proficiency in Python and SQL for scalable back-end systems.
• Skilled with TypeScript, React, and Next.js for high-quality front-end work.

Responsibilities

• Build and ship production features end-to-end across Python, SQL, and Next.js.
• Design APIs, data pipelines, and UIs that make complex outputs intuitive.
• Improve quality and speed through testing and CI/CD.

Skills

Python

SQL

TypeScript

React

Next.js

CI/CD

Tools

GCP

Job description

Electric Twin is building the future of strategic decision-making.

We use large language models (LLMs) to simulate human behaviour, creating science-based synthetic populations that mirror real markets and demographics.

Our platform gives leaders in business and government a new way to explore outcomes - from qualitative polling and quantitative analysis to simulated focus groups and one-to-one discussions. The result: faster insight, stronger evidence, and more confident decisions.

With a unique proposition in the rapidly developing generative AI sector, Electric Twin is poised for significant growth. We're backed by world-class leadership, including:

• Alex Cooper (Co-founder) - Former COO at UNDO, Director of Mass Testing for the UK's Department of Health, and Advisor for 10 Downing Street
• Ben Warner (Co-founder) - Former Chief Advisor on Digital and Data to the UK Prime Minister, Data Scientist at Faculty, and EPSRC Research Fellow at UCL

We're now looking for a Senior Full-Stack Engineer to help us build the next generation of applied AI tools.

What You'll Do

• Build and ship production features end-to-end across Python, SQL, and Next.js.
• Design APIs, data pipelines, and UIs that make complex model outputs intuitive and actionable.
• Own architecture and design decisions - schemas, modularisation, and system patterns.
• Refactor and optimise existing systems for performance and maintainability.
• Improve quality and speed through testing and CI/CD.
• Work side-by-side with founders and senior engineers - we collaborate on-site four days a week.

What We're Looking For

• 5+ years' experience building production software (exceptional 4+ considered).
• Strong proficiency in Python and SQL for scalable back-end systems.
• Skilled with TypeScript, React, and Next.js for high-quality front-end work.
• Solid testing habits and CI/CD experience.
• Product-focused mindset and attention to code quality.
• Comfortable working on-site in a fast-paced, collaborative startup.

Nice to Have

• Experience with data-heavy or high-throughput systems.
• Exposure to applied AI or LLM integrations (no model training required).
• Familiarity with GCP, especially IAM, networking, and security.

Why Electric Twin

• Impact - Shape both the product and how we build it.
• Pace - We ship weekly; your work goes live fast.
• Team - Small, sharp, and experienced.
• Learning - Work hands-on with cutting-edge AI applications that matter.