# What are MCP Servers?

DevFeed: [What are MCP Servers?](<https://devfeed.tech/articles/what-are-mcp-servers-1711.md>)

Original publisher: [Read original article](<https://fly.io/blog/mcps-everywhere/>)

Published: 2025-06-12T00:00:00Z

Content type: article

Language: en

Sources: [The Fly Blog](<https://devfeed.tech/sources/the-fly-blog.md>)

Topics: [Model Context Protocol](<https://devfeed.tech/topics/model-context-protocol.md>), [Model Context Protocol (MCP)](<https://devfeed.tech/topics/model-context-protocol-mcp.md>), [API](<https://devfeed.tech/topics/api.md>), [Large Language Model](<https://devfeed.tech/topics/llm.md>), [browser](<https://devfeed.tech/topics/browser.md>), [cursor](<https://devfeed.tech/topics/cursor.md>), [Visual Studio Code](<https://devfeed.tech/topics/visual-studio-code.md>), [fly.io](<https://devfeed.tech/topics/fly-io.md>)

Tags: [api](<https://devfeed.tech/tags/api.md>), [cdn](<https://devfeed.tech/tags/cdn.md>), [close-to-users](<https://devfeed.tech/tags/close-to-users.md>), [cursor](<https://devfeed.tech/tags/cursor.md>), [deploy-app-servers](<https://devfeed.tech/tags/deploy-app-servers.md>), [docker](<https://devfeed.tech/tags/docker.md>), [elixir](<https://devfeed.tech/tags/elixir.md>), [fly](<https://devfeed.tech/tags/fly.md>), [fly-io](<https://devfeed.tech/tags/fly-io.md>), [heroku-alternative](<https://devfeed.tech/tags/heroku-alternative.md>), [heroku-competitor](<https://devfeed.tech/tags/heroku-competitor.md>), [hosting](<https://devfeed.tech/tags/hosting.md>), [http](<https://devfeed.tech/tags/http.md>), [i](<https://devfeed.tech/tags/i.md>), [llm](<https://devfeed.tech/tags/llm.md>), [mcp](<https://devfeed.tech/tags/mcp.md>), [model-context-protocol](<https://devfeed.tech/tags/model-context-protocol.md>), [networking](<https://devfeed.tech/tags/networking.md>), [postgresql-clusters](<https://devfeed.tech/tags/postgresql-clusters.md>), [servers](<https://devfeed.tech/tags/servers.md>), [sse](<https://devfeed.tech/tags/sse.md>), [vscode](<https://devfeed.tech/tags/vscode.md>)

## AI overview

This article explains Model Context Protocol (MCP) through analogies to USB-C, Alexa Skills, and API 2.0. It describes how MCP connects AI models to data sources and tools, supports multiplexing and server push, and provides introspection about available tools and their arguments.

## Source excerpt

With Fly.io, you can get your app running globally in a matter of minutes, and with MCP servers you can integrate with Claude, VSCode, Cursor and many more AI clients. Try it out for yourself! The introduction to Model Context Protocol starts out with: MCP is an open protocol that standardizes how applications provide context to LLMs. Think of MCP like a USB-C port for AI applications. Just as USB-C provides a standardized way to connect your devices to various peripherals and accessories, MCP provides a standardized way to connect AI models to different data sources and tools. That paragraph, to me, is both comforting ("USB for LLM"? Cool! Got it!), and simultaneously vacuous (Um, but what do I actually do with this?). I've been digging deeper and have come up with a few more analogies and observations that make sense to me. Perhaps one or more of these will help you. MCPs are Alexa Skills You buy an Echo Dot and a Hue light. You plug them both in and connect them to your Wi-Fi. There is one more step you need to do: you need to install and enable the Philips Hue skill to connect the two. Now you might be using Siri or Google Assistant. Or you may want to connect a Ring Doorbell camera or Google Nest Thermostat. But the principle is the same, though the analogy is slightly stronger with a skill (which is a noun) as opposed to the action of pairing your Hue Bridge with Apple HomeKit (a verb). MCPs are API 2.0 HTTP 1.1 is simple. You send a request, you get a response. While there are cookies and sessions, it is pretty much stateless and therefore inefficient, as each request needs to establish a new connection. WebSockets and Server-Sent Events (SSE) mitigate this a bit. HTTP 2.0 introduces features like multiplexing and server push. When you visit a web page for the first time, your browser can now request all of the associated JavaScript, CSS, and images at once, and the server can respond in any order. APIs today are typically request/response. MCPs support multi