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Prerequisites

  • Node.js 22+ — check with node --version
  • npm — comes with Node.js

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Create Your First Schema

1

Install FlowMCP Core

Create a new project and install the core library:
mkdir my-flowmcp-project
cd my-flowmcp-project
npm init -y
npm install flowmcp-core
Add "type": "module" to your package.json for ES module support.
2

Write a Schema

Create a file called coingecko-ping.mjs:
export const main = {
    namespace: 'coingecko',
    name: 'Ping',
    description: 'Check CoinGecko API server status',
    version: '2.0.0',
    root: 'https://api.coingecko.com/api/v3',
    requiredServerParams: [],
    requiredLibraries: [],
    headers: {},
    routes: {
        ping: {
            method: 'GET',
            path: '/ping',
            description: 'Check if CoinGecko API is online',
            parameters: [],
            output: {
                mimeType: 'application/json',
                schema: {
                    type: 'object',
                    properties: {
                        gecko_says: { type: 'string', description: 'Response message' }
                    }
                }
            }
        }
    }
}
This schema declares a single route that calls the CoinGecko ping endpoint. No API key required.
3

Validate and Call

Create a file called test.mjs:
import { FlowMCP } from 'flowmcp-core'
import { main } from './coingecko-ping.mjs'

// Validate the schema against 79 rules
const { status, messages } = FlowMCP.validateSchema( { schema: main } )
console.log( status ? 'Schema valid!' : messages )

// Call the API
const result = await FlowMCP.fetch( {
    schema: main,
    routeName: 'ping',
    userParams: {},
    serverParams: {}
} )

console.log( result.dataAsString )
// → {"gecko_says":"(V3) To the Moon!"}
Run it:
node test.mjs
You should see Schema valid! followed by the CoinGecko ping response.
4

Run as MCP Server

Create a file called server.mjs to expose your schema as an MCP tool:
import { FlowMCP } from 'flowmcp-core'
import { Server } from '@modelcontextprotocol/sdk/server/index.js'
import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js'
import { main } from './coingecko-ping.mjs'

const server = new Server(
    { name: 'my-first-server', version: '1.0.0' },
    { capabilities: { tools: {} } }
)

FlowMCP.activateServerTools( { server, schemas: [main] } )

const transport = new StdioServerTransport()
await server.connect( transport )
Install the MCP SDK:
npm install @modelcontextprotocol/sdk
Run the server:
node server.mjs
Your MCP server is now running over stdio. AI clients like Claude Desktop can connect to it and call the coingecko__ping tool.
The tool name is auto-generated from namespace + routeName: coingecko__ping. AI clients see this name along with the route description to decide when to call it.

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What Just Happened?

  1. You declared an API endpoint as a schema (no server code needed)
  2. FlowMCP validated the schema structure (79 rules)
  3. FlowMCP called the API with correct URL construction and headers
  4. FlowMCP exposed the schema as an MCP tool with auto-generated Zod validation
The same pattern works for any REST API — add authentication via requiredServerParams and headers, add parameters via the parameters array, add response transformation via the handlers export.

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What’s Next

Schema Creation

Learn the full schema format with authentication, parameters, and handlers

CLI Reference

Search, activate, and call 187+ pre-built schemas from the command line

Examples

Real-world schema examples for common APIs