Senior Backend Engineer, MCP / AI Integrations (Python/AWS/MCP)

NO AGENCIES. INDEPENDENT FREELANCERS ONLY. READ THIS FIRST: This role builds MCP (Model Context Protocol) servers that expose real production APIs to AI agents, with real authentication, scoping and audit controls. If your MCP or AI agent experience is limited to demos and tutorials, and you cannot explain how you would enforce least privilege on an agent-initiated write, do not apply. This will be the first thing we test. You will own MCP server development: the secure layer that lets AI platforms and agents work with the client's vendor APIs. Shipped MCP experience is a strong plus. A strong Python API engineer who has built LLM tool-calling or agent integrations and can reason about security will also succeed. Full-time, long-term engagement. Key Responsibilities: • Build MCP servers that securely expose vendor APIs to AI platforms and agents • Design authentication, scoping and rate controls for agent-initiated calls against production systems • Implement logging, monitoring and guardrails for agent activity • Document MCP tools and schemas so client teams and AI platforms can adopt them • Work with the lead architect on the MCP security model and evolve it as the protocol matures • Build general REST and GraphQL integrations with third-party business applications when MCP demand is light Requirements: • 5+ years of backend engineering with strong Python (will be tested during screening) • MCP server development experience, or strong demonstrated ability to work with MCP: agent tooling, LLM function calling, or AI platform integrations • REST and GraphQL API design and integration • OAuth, API authentication, webhooks, error handling and monitoring • AWS deployment with Docker and CI/CD • Security-first mindset: least privilege, audit trails, input validation • Fluent English • Minimum 4 hours daily overlap with US Eastern time, full-time availability Nice to Have: • Published or open-source MCP servers (include links in your application) • Experience with Anthropic, OpenAI or similar platform APIs and agent frameworks • SQL and BigQuery • Enterprise SaaS integration background