Full Stack Developer

Job Description

About The Role • You will design and build applications that solve real business problems. This may include internal tools, client-facing applications, dashboards, portals, workflow automation, data-driven interfaces and AI-enabled features. • We take an AI-first approach to development. The successful candidate must be fluent in AI-assisted development, using tools such as Claude Code, Cursor, GitHub Copilot or similar as part of their normal workflow to accelerate delivery across the stack. • You will be expected to apply strong engineering judgement when using AI-assisted development tools, including reviewing, testing and taking responsibility for all code produced. This includes ensuring that AI-generated code meets appropriate standards for quality, security, maintainability and performance. • What You’ll Be Doing • Building applications for internal and client use. • Developing user interfaces, back-end logic, APIs and database-backed functionality. • Integrating with AI platforms, LLM APIs and third-party systems. • Configuring prompts, agents or workflows where required. • Connecting applications to data sources, APIs and business systems. • Testing, improving and maintaining applications after release. • Working with internal teams and clients to turn ideas into working solutions. • Ensuring applications are secure, maintainable and suitable for business use. • What We’re Looking For • We are looking for a practical, capable developer who can take requirements and turn them into working applications. • You should be comfortable across the main parts of application development, including front-end interfaces, back-end logic, databases, APIs and integrations. You should also be fluent in AI-assisted development and understand how to integrate AI capabilities where they add value. • This role would suit an experienced full stack developer who has built real applications, can make sensible technical decisions and is comfortable taking ownership of delivery. • Essential Experience • Typically 6+ years’ commercial software development experience. • Strong experience building modern software applications. • Strong JavaScript and/or TypeScript experience. • Experience with frameworks such as React, Next.js or similar. • Experience with Node.js, including building APIs and application logic. • Experience working with databases and data models, such as PostgreSQL, Supabase, Firebase or similar. • Experience designing and integrating REST APIs. • Understanding of authentication, authorisation and secure application design. • Fluent in AI-assisted development using tools such as Claude Code, Cursor, GitHub Copilot or similar. • Able to review, test and take responsibility for all code produced, including AI-generated code. • Experience integrating AI tools, LLMs or AI-enabled features into applications. • Relevant AI Experience • Relevant AI experience may include: • OpenAI, Anthropic Claude, Azure OpenAI, Microsoft Copilot or similar platforms. • LLM API integration. • Prompt design and structured AI outputs. • AI agents or workflow automation. • Retrieval-augmented generation, known as RAG. • Function calling, tool calling or similar approaches. • Understanding AI risks, including accuracy, validation, security and data privacy. • We do not expect candidates to have used every AI tool or framework. The key requirement is practical experience using AI to build, improve and enhance applications. • Useful Technical Skills • Relevant technologies may include: • Application development: React, Next.js, TypeScript, Node.js, Python • Data and APIs: PostgreSQL, Supabase, Firebase, REST APIs • Cloud and deployment: Vercel, Azure, GitHub • AI development: OpenAI, Anthropic Claude, Azure OpenAI, LangChain, LangGraph or similar frameworks • We are open on the exact technology stack. The key requirement is that you can build high-quality applications and integrate AI capabilities in a practical, secure and maintainable way. • Why Join Celon? • · Competitive Salary plus Benefits • · Fully remote role aligned to UK working hours • · HMO with up to 3 Dependents • · Paid Vacation and Sick Leaves • · Paid PH and UK Holidays • · Company Equipment Provided • · Join a delivery-focused consultancy with real technical ownership