Senior Full Stack Next.js Developer

Madfish; Remote; GBP 60,000 - 80,000; Full time

Job summary

A leading AI software company in the United Kingdom is looking for a Senior Next.js Developer to join their innovative team. You will work on developing a cutting-edge AI App Builder that allows for rapid app creation using AI-generated code. Successful candidates will have strong experience with Next.js, React, and TypeScript, alongside a deep understanding of performance optimization and error handling. This is a fully remote position offering flexible hours and a collaborative environment.

Benefits

Fully remote work

Flexible hours

Collaborative work environment

Qualifications

• Strong experience with modern web frameworks, particularly Next.js and React.
• Hands-on knowledge of JavaScript runtime concepts and error handling.
• Familiarity with AI tools and low-code platforms is a plus.

Responsibilities

• Develop a live preview system for AI-generated React code.
• Implement hot-reload logic for real-time updates.
• Create an elegant error boundary system for runtime errors.

Skills

Next.js 14+

React 18+

TypeScript

TailwindCSS

Error handling

Performance optimization

Tools

Babel Standalone

PostMessage API

Job description

We’re building something big: an AI App Builder where artificial intelligence writes the code, turning developers’ and founders’ ideas into live apps in just minutes.

Our MVP is ready. Now we’re leveling up. Making the platform faster, smarter, and more powerful.

We’re looking for a Senior Next.js Developer who’s excited to help shape the future of AI-powered software creation.

⚙️ What You’ll Be Building

• A real-time “Live Preview” system that runs AI-generated React code inside an isolated iframe
• Hot-reload logic for instant code updates
• An elegant Error Boundary system that catches and displays runtime errors beautifully
• A flexible front-end environment using TailwindCSS, Babel, and React 18
• Deep performance optimizations. 50+ concurrent previews, Worker-based transforms, caching, and more

🧠 What We’re Looking For

• Strong experience with Next.js 14+, React 18+, TypeScript, and TailwindCSS
• Familiarity with Server Components, App Router, and modern React patterns
• Hands‑on experience with Babel Standalone, iframe sandboxing, and postMessage API (super important)
• Solid understanding of JavaScript runtime, scope isolation, and module execution
• Care for error handling, security, and performance
• Bonus: experience with AI tools, no-code, or low-code builders

💡 You’ll Fit Right In If You…

• Think like a system builder, not just a coder
• Love figuring out how things work under the hood
• Care about architecture, performance, and great UX
• Are genuinely curious about AI, automation, and the future of software
• Can read and write solid technical English

🌍 Why Join Us?

• Be part of the real AI revolution, not just the hype
• Your code will reach thousands of developers worldwide
• Work with a global team of top engineers pushing creative boundaries
• Fully remote, flexible hours, zero micromanagement

💬 Final Thought

“In the future, apps won’t be built by people. They’ll be built by AIs that write code for people.

But the ones building those AIs… are still us.” 💡