Senior Software Engineer

Salary: £90,000 - 90,000 per year

Requirements:

• Strong commercial experience with Python for backend and integration development.
• Strong TypeScript/JavaScript and React experience building production applications.
• Strong API design experience, including REST and/or GraphQL, authentication, authorisation, versioning and streaming.
• Hands-on experience with MCP (Model Context Protocol) or comparable tool/plugin integration technologies, alongside an interest in AI agents and agent-to-agent connectivity.
• Solid experience with AWS, ideally including services such as Lambda, ECS, API Gateway, S3, CloudFront, Cognito and IAM.
• Experience designing and operating distributed or event-driven systems.
• A strong understanding of observability, testing and CI/CD practices.
• Experience working with data platforms or stores such as MongoDB, OpenSearch or Databricks.
• Experience integrating internal systems and third-party services securely and reliably.
• Experience working closely with designers to deliver production-quality frontend applications.
• A good understanding of accessibility and frontend performance.
• Experience with RAG, AI agents, tool use or other generative AI application patterns would be advantageous, although deep ML expertise isnt required.

Responsibilities:

• Own the application and integration layer of AI products end to end, covering APIs, integrations, service boundaries and frontend development.
• Design, build and maintain MCP servers that safely expose systems, content and tooling to AI agents.
• Develop agent-to-agent connectivity, including message contracts, state management, retries and failure handling.
• Design clear, scalable APIs using REST and/or GraphQL, including authentication, authorisation, versioning and streaming interfaces such as SSE or WebSockets.
• Build production frontend applications using React, TypeScript and JavaScript.
• Work closely with UX and product teams to turn designs into accessible, responsive and intuitive interfaces.
• Develop AI-specific user experiences including streaming responses, citations, source information, agent/tool progress and graceful error handling.
• Integrate with internal platforms and third-party services, considering security, scalability, performance and reliability.
• Establish automated testing across backend and frontend applications, including unit, contract and end-to-end testing.
• Work with the platform engineering team on deployment, observability, logging, tracing and operational readiness.
• Act as the technical owner for the application and integration layer, making and documenting key architectural decisions.
• Provide technical guidance, code reviews and mentoring to other engineers.

Technologies:

• AI
• AI Agents
• API
• AWS
• Lambda
• OpenSearch
• Backend
• CI/CD
• Cloud
• Databricks
• Frontend
• GraphQL
• IAM
• JavaScript
• MCP
• MongoDB
• Python
• RAG
• REST
• React
• Security
• TypeScript
• UX UI Design
• Support

More:

We are recruiting for a Senior Software Engineer to join our growing AI team and take ownership of the application and integration layer behind a new generation of AI-powered products. This is a genuinely full-stack engineering role at the intersection of software engineering, APIs, cloud infrastructure and generative AI, with opportunities to shape engineering standards and architecture for future products. The role offers genuine ownership and the chance to work closely with UX, product and platform engineering teams in an AI-focused environment. The Portfolio Group are acting on behalf of our client in recruiting for this position.

last updated 36 week of 2026