From REST API to MCP Server: Convert Your Spring REST APIs into AI Tools

In the rapidly evolving world of Artificial Intelligence, connecting our existing apps with AI Tools/Agents is no longer just a good idea — it’s a must-have. Imagine your existing systems communicating with AI tools, allowing them to understand and work with your data and features using everyday language. You can do this with little effort, easily turning your Spring APIs into strong AI tools thanks to Spring AI’s Model Context Protocol (MCP) server.

In our previous article, I explained what MCP is and why it’s important, even building a practical MCP server for managing blog posts. If you’re curious about how to create an MCP server from scratch, you might want to check that out. Building on that, making our existing systems AI-available is a crucial topic. In this article, I’ll show you just how easy it is to transform a typical Spring Boot REST API into an MCP server.

Understanding The Existing REST API Project

Let’s explain a bit about the existing REST Apı model. In our Finance Wallet application, we have endpoints like: creating a wallet,/api/wallets for retrieving all wallets or /api/wallets/{id} for a specific one. These are designed for direct programmatic access by other applications, web frontends, or mobile clients. They are…