FullStack Developer

FULLY REMOTE

OUTSIDE IR35

We are looking for a Full Stack Developer with strong Node.js skills to develop and support frontend and backend systems. A central part of the role is connecting our AI platform with internal and third-party services through APIs and Model Context Protocol (MCP) integrations. You will build features across the application stack and help ensure they operate reliably in production.

Key responsibilities

• Develop backend services in Node.js and JavaScript/TypeScript.
• Build and maintain frontend functionality using an appropriate modern web framework.
• Design, implement, document and integrate APIs connecting our platform, customer applications and external services.
• Develop MCP clients and servers that expose approved tools, resources and capabilities to AI applications.
• Define and validate JSON schemas, API contracts and integration payloads.
• Implement authentication, authorisation, secrets management and appropriate access controls.
• Build database models, queries and migrations that support application requirements.
• Build dependable integrations using timeouts, retries, rate-limit handling and duplicate-request protection where appropriate.
• Validate AI-requested tool calls and enforce permissions before executing actions.
• Add logging, monitoring and useful error handling to support troubleshooting and service reliability.
• Write automated tests, review code and maintain deployment pipelines and technical documentation.
• Work with AI specialists, frontend developers and business analysts to deliver complete features.

Essential experience and skills

• Strong commercial experience with Node.js and JavaScript/TypeScript.
• Demonstrable experience delivering both frontend and backend software.
• Practical experience designing and integrating APIs, including authentication and JSON data handling.
• Working knowledge of MCP and practical experience building MCP integrations or closely comparable AI tool integrations.
• Experience with at least one modern frontend framework, such as React, Vue or Angular.
• Experience with relational or document databases and sound data modelling principles.
• Understanding of secure development, automated testing, version control and deployment practices.
• Ability to investigate problems across the application stack and explain technical decisions clearly.

Desirable experience

• AI platforms, large language model APIs and tool-calling workflows.
• OAuth integrations, webhooks, queues and event-driven processing.
• Cloud infrastructure, containers and continuous integration/delivery.
• Multi-customer applications with strict separation of customer data.