The Model Communication Protocol (MCP) is an emerging open standard that allows AI agents to interact with external services through a uniform interface. Instead of writing custom integrations for each API, an MCP server exposes a set of tools that a client AI can discover and invoke dynamically. This decoupling means API providers can evolve their back ends or add new operations without breaking existing AI clients. At the same time, AI developers gain a consistent protocol to call, inspect, and combine external capabilities. Below are eight solutions for converting existing APIs into MCP servers. This article explains each solution’s purpose, technical approach, implementation steps or requirements, unique features, deployment strategies, and suitability for different development workflows.
FastAPI-MCP: Native FastAPI Extension
FastAPI-MCP is an open-source library that integrates directly with Python’s FastAPI framework. All existing REST routes become MCP tools by instantiating a single class and mounting it on your FastAPI app. Input and output schemas defined via Pydantic models carry over automatically, and the tool descriptions derive from your route documentation. Authentication and dependency injection behave exactly as in normal FastAPI endpoints, ensuring that any security or validation logic you already have remains effective.
Under the hood, FastAPI-MCP hooks into the ASGI application and routes MCP protocol calls to the appropriate FastAPI handlers in-process. This avoids extra HTTP overhead and keeps performance high. Developers install it via pip, add a minimal snippet such as:
from fastapi import FastAPIfrom fastapi_mcp import FastApiMCPapp = FastAPI()mcp = FastApiMCP(app)mcp.mount(path="/mcp")The resulting MCP server can run on the same Uvicorn process or separately. Because it is fully open-source under the MIT license, teams can audit, extend, or customize it as needed.
RapidMCP: Zero-Code REST-to-MCP Conversion Service
RapidMCP provides a hosted, no-code pathway to transform existing REST APIs, particularly those with OpenAPI specifications, into MCP servers without changing backend code. After registering an account, a developer points RapidMCP at their API’s base URL or uploads an OpenAPI document. RapidMCP then spins up an MCP server in the cloud that proxies tool calls back to the original API.
Each route becomes an MCP tool whose arguments and return types reflect the API’s parameters and responses. Because RapidMCP sits in front of your service, it can supply usage analytics, live tracing of AI calls, and built-in rate limiting. The platform also plans self-hosting options for enterprises that require on-premises deployments. Teams who prefer a managed experience can go from API to AI-agent compatibility in under an hour, at the expense of trusting a third-party proxy.
MCPify: No-Code MCP Server Builder with AI Assistant
MCPify is a fully managed, no-code environment where users describe desired functionality in natural language, such as “fetch current weather for a given city”, and an AI assistant generates and hosts the corresponding MCP tools. The service hides all code generation, infrastructure provisioning, and deployment details. Users interact via a chat or form interface, review automatically generated tool descriptions, and deploy with a click.
Because MCPify leverages large language models to assemble integrations on the fly, it excels at rapid prototyping and empowers non-developers to craft AI-accessible services. It supports common third-party APIs, offers one-click sharing of created servers with other platform users, and automatically handles protocol details such as streaming responses and authentication. The trade-off is less direct control over the code and reliance on a closed-source hosted platform.
Speakeasy: OpenAPI-Driven SDK and MCP Server Generator
Speakeasy is known for generating strongly typed client SDKs from OpenAPI specifications, and it extends this capability to MCP by producing a fully functional TypeScript MCP server alongside each SDK. After supplying an OpenAPI 3.x spec to Speakeasy’s code generator, teams receive:
- A typed client library for calling the APIDocumentation derived directly from the specA standalone MCP server implementation in TypeScript
The generated server wraps each API endpoint as an MCP tool, preserving descriptions and models. Developers can run the server via a provided CLI or compile it to a standalone binary. Because the output is actual code, teams have full visibility and can customize behavior, add composite tools, enforce scopes or permissions, and integrate custom middleware. This approach is ideal for organizations with mature OpenAPI workflows that want to offer AI-ready access in a controlled, maintainable way.
Higress MCP Marketplace: Open-Source API Gateway at Scale
Higress is an open-source API gateway built atop Envoy and Istio, extended to support the MCP protocol. Its conversion tool takes an OpenAPI spec and generates a declarative YAML configuration that the gateway uses to host an MCP server. Each API operation becomes a tool with templates for HTTP requests and response formatting, all defined in configuration rather than code. Higress powers a public “MCP Marketplace” where multiple APIs are published as MCP servers, enabling AI clients to discover and consume them centrally. Enterprises can self-host the same infrastructure to expose hundreds of internal services via MCP. The gateway handles protocol version upgrades, rate limiting, authentication, and observability. It is particularly well suited for large-scale or multi-API environments, turning API-MCP conversions into a configuration-driven process that integrates seamlessly with infrastructure-as-code pipelines.
Django-MCP: Plugin for Django REST Framework
Django-MCP is an open-source plugin that brings MCP support to the Django REST Framework (DRF). By applying a mixin to your view sets or registering an MCP router, it automatically exposes DRF endpoints as MCP tools. It introspects serializers to derive input schemas and uses your existing authentication backends to secure tool invocations. Underneath, MCP calls are translated into normal DRF viewset actions, preserving pagination, filtering, and validation logic.
Installation requires adding the package to your requirements, including the Django-MCP application, and configuring a route:
from django.urls import pathfrom django_mcp.router import MCPRouterrouter = MCPRouter()router.register_viewset('mcp', MyModelViewSet)urlpatterns = [ path('api/', include(router.urls)),]This approach allows teams already invested in Django to add AI-agent compatibility without duplicating code. It also supports custom tool annotations via decorators for fine-tuned naming or documentation.
GraphQL-MCP: Converting GraphQL Endpoints to MCP
GraphQL-MCP is a community-driven library that wraps a GraphQL server and exposes its queries and mutations as individual MCP tools. It parses the GraphQL schema to generate tool manifests, mapping each operation to a tool name and input type. When an AI agent invokes a tool, GraphQL-MCP constructs and executes the corresponding GraphQL query or mutation, then returns the results in a standardized JSON format expected by MCP clients. This solution is valuable for organizations using GraphQL who want to leverage AI agents without settling on a REST convention or writing bespoke GraphQL calls. It supports features like batching, authentication via existing GraphQL context mechanisms, and schema stitching to combine GraphQL services under one MCP server.
gRPC-MCP: Bridging gRPC Services for AI Agents
gRPC-MCP focuses on exposing high-performance gRPC services to AI agents through MCP. It uses protocol buffers’ service definitions to generate an MCP server that accepts JSON-RPC-style calls, internally marshals them to gRPC requests, and streams responses. Developers include a small adapter in their gRPC server code:
import "google.golang.org/grpc"import "grpc-mcp-adapter"func main() { srv := grpc.NewServer() myService.RegisterMyServiceServer(srv, &MyServiceImpl{}) mcpAdapter := mcp.NewAdapter(srv) http.Handle("/mcp", mcpAdapter.Handler()) log.Fatal(http.ListenAndServe(":8080", nil))}This makes it easy to bring low-latency, strongly typed services into the MCP ecosystem, opening the door for AI agents to call business-critical gRPC methods directly.
Choosing the Right Tool
Selecting among these eight solutions depends on several factors:
- Preferred development workflow: FastAPI-MCP and Django-MCP for code-first integration, Speakeasy for spec-driven code generation, GraphQL-MCP or gRPC-MCP for non-REST paradigms.Control versus convenience: Libraries like FastAPI-MCP, Django-MCP, and Speakeasy give full code control, while hosted platforms like RapidMCP and MCPify trade off some control for speed and ease.Scale and governance: Higress shines when converting and managing large numbers of APIs in a unified gateway, with built-in routing, security, and protocol upgrades.Rapid prototyping: MCPify’s AI assistant allows non-developers to spin up MCP servers instantly, which is ideal for experimentation and internal automation.
All these tools adhere to the evolving MCP specification, ensuring interoperability among AI agents and services. By choosing the right converter, API providers can accelerate the adoption of AI-driven workflows and empower agents to orchestrate real-world capabilities safely and efficiently.
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