FullStack Developer

M4 Partners; United States; Remote; USD 90,000 - 150,000; Full time

Job summary

M4 Partners is seeking a Full Stack Developer with strong Node.js skills to connect our AI platform with internal and third-party services through APIs and MCP integrations. You will build features across the stack and ensure reliable production operations.

Responsibilities include developing backend services, building frontend functionality, and designing APIs with authentication and data handling. You will work with AI specialists and business analysts to deliver complete features, with a

Qualifications

• Strong commercial experience with Node.js and JavaScript/TypeScript.
• Experience delivering both frontend and backend software.
• Design and integrate APIs including authentication and JSON data handling.
• Knowledge of MCP and building MCP integrations or similar AI tool integrations.
• Experience with at least one modern frontend framework (React, Vue, Angular).
• Experience with relational or document databases and solid data modeling.
• Understanding of secure development, automated testing, version control and deployment practices.
• Ability to investigate problems across the application stack and explain technical decisions clearly.

Responsibilities

• Develop backend services in Node.js and JavaScript/TypeScript.
• Build and maintain frontend functionality using a modern web framework.
• Design, implement, document and integrate APIs connecting our platform and external services.
• Develop MCP clients and servers exposing tools, resources and capabilities to AI apps.
• Define and validate JSON schemas, API contracts and integration payloads.
• Implement authentication, authorization, secrets management and access controls.
• Build database models, queries and migrations to support requirements.
• Create reliable integrations with timeouts, retries, and rate-limit handling.

Skills

Node.js

JavaScript/TypeScript

Frontend framework

APIs design

MCP integrations

Databases

Security & testing

Version control

Tools

React

Vue

Angular

Job description

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