Principal JavaScript/Node.js MCP Engineer (FinTech Project)

Are you passionate about building scalable AI integration platforms and defining engineering standards that impact entire organizations? We are looking for a Principal-level JavaScript/Node.js Engineer to lead the development of enterprise-wide MCP foundations and reusable platform capabilities for one of Europe’s fastest-growing FinTech products.

In this role, you will combine hands-on Back-End engineering, platform architecture, and technical leadership to help multiple product teams adopt consistent MCP integration patterns. You will work with TypeScript, Node.js, distributed systems, and modern AI orchestration approaches while shaping internal engineering standards and developer experience practices.

We at Sigma Software offer the opportunity to work on cutting-edge AI-enabled platform initiatives in a collaborative international environment where your technical decisions will directly influence large-scale engineering adoption and long-term platform strategy.

CUSTOMER

Our Customer is one of Europe’s fastest-growing FinTech companies, delivering a comprehensive financial infrastructure platform for businesses. The company provides embedded financial services, including virtual cards, bank transfers, account management, and payment operations through scalable APIs and modern financial technology solutions. Operating in a high-scale and rapidly evolving environment, the Customer places strong emphasis on engineering excellence, platform scalability, and architectural consistency.

PROJECT

The project focuses on building the engineering foundations for enterprise-wide MCP adoption across multiple product teams. The goal is to establish shared architecture standards, reusable TypeScript/Node.js libraries, SDKs, templates, and development practices that enable teams to build scalable MCP-compatible integrations consistently.

As a Principal JavaScript/Node.js MCP Engineer, you will drive platform architecture decisions, define engineering standards, and build reusable tooling for MCP servers, agent orchestration, context management, authentication, and integration workflows. The role also includes defining architectural guidance for MCP, A2A communication, APIs, and service-to-service integrations while helping scale AI integration expertise across the organization.

Key Technologies: TypeScript, JavaScript, Node.js, AWS, MCP, LLM Integrations, APIs, Distributed Systems, SDK Development, Microservices, AI Orchestration.

• Design and implement core MCP platform capabilities, including MCP clients, servers, tool invocation workflows, and integrations with existing backend services
• Define reusable reference architectures, engineering standards, and development patterns for MCP-compatible systems
• Build shared TypeScript/Node.js libraries, SDKs, starter kits, templates, and tooling that accelerate adoption across engineering teams
• Design scalable approaches for conversation state management, agent orchestration, context handling, authentication, and versioning
• Establish architectural guidelines for selecting appropriate integration patterns, including MCP, A2A, APIs, and service-to-service communication
• Collaborate with multiple engineering teams to review technical designs, ensure consistency, and drive platform adoption
• Create technical documentation, best practices, and onboarding materials for developers working with MCP integrations
• Mentor engineers and provide technical leadership across platform and backend initiatives
• Contribute to long-term platform scalability, maintainability, and engineering governance

• At least 7 years of production experience with JavaScript, TypeScript, and Node.js
• Extensive experience in Back-End or platform engineering, including technical leadership at Principal or Staff level
• Proven expertise in designing distributed systems, APIs, SDKs, developer platforms, or Back-End frameworks
• Deep understanding of scalable architecture design, interface contracts, versioning strategies, and reusable platform components
• Hands-on experience with MCP clients, servers, resources, tools, and LLM tool invocation patterns
• Experience building AI-enabled platforms or LLM-based integrations
• Knowledge of Developer Experience best practices and internal platform engineering
• Experience driving technical initiatives across multiple engineering teams and stakeholders
• Experience defining enterprise engineering standards and governance models
• Ability to balance strategic architectural thinking with hands-on implementation
• Experience working in cloud-native and microservice-based environments
• At least an Upper-Intermediate level of English

WILL BE A PLUS

• Experience with Agent-to-Agent communication and orchestration frameworks
• Familiarity with FinTech or regulated environments
• Experience designing reusable SDKs or integration frameworks

PERSONAL PROFILE

• Strong technical leadership and ownership mindset
• Excellent collaboration and cross-team communication skills
• Ability to drive engineering alignment in complex organizations
• Proactive problem solver with strategic thinking capabilities
• Passion for platform engineering, developer enablement, and scalable architecture
• Comfortable operating in fast-paced and evolving technical environments