Welcome to Massimo

Why Massimo?

Type-Safe Clients

Automatically generate TypeScript types from your OpenAPI or GraphQL schemas for complete type safety in your applications.

Framework Agnostic

Works seamlessly with any JavaScript framework - Node.js, React, Vue, Angular, and more. Use in both server and browser environments.

Developer Experience

Simple CLI commands to generate clients, with support for custom headers, authentication, and request/response interceptors.

Production Ready

Battle-tested in production environments with built-in error handling, retry logic, and telemetry support.

Platform-Specific Clients

Massimo generates optimized clients for different environments:

Node.js Client

Powered by Undici - Uses the high-performance Undici HTTP client for optimal performance in Node.js environments. Features connection pooling, HTTP/2 support, and advanced request pipelining.

Web Client

Powered by Fetch - Uses the native Fetch API for browser compatibility. Lightweight bundle size with full support for modern web standards and browser features.

Node.js Client Features

• Built on Undici for maximum performance
• Connection pooling and keep-alive
• HTTP/2 and pipelining support
• Stream processing for large responses
• Native Node.js integration

Web Client Features

• Uses native Fetch API
• Minimal bundle size
• Browser-native error handling
• CORS support
• Works with all modern frameworks

Quick Start

Generate a typed client for your API in seconds:

# For OpenAPI (auto-detects ESM/CommonJS from package.json)
npx massimo-cli http://api.example.com/openapi.json --name my-client

# For GraphQL with explicit module format
npx massimo-cli http://api.example.com/graphql --name my-client --type graphql --module esm

Then use it in your code:

ESM (ECMAScript Module)

import client from './my-client/my-client.mjs'

const api = await client({ url: 'http://api.example.com' })
const result = await api.getUsers()

Features

• OpenAPI & GraphQL Support - Generate clients from OpenAPI 3.0+ specs or GraphQL schemas
• TypeScript Types - Full type safety with automatically generated TypeScript definitions
• Module Format Support - Automatic detection and generation of ESM or CommonJS modules
• TypeScript Declaration Extensions - Smart generation of .d.mts and .d.cts files for module-specific type definitions
• Dual Runtime Support - Optimized clients for both Node.js (Undici) and browsers (Fetch)
• Authentication - Built-in support for custom headers and authentication strategies
• Fastify Integration - First-class Fastify plugin for seamless server integration
• Error Handling - Comprehensive error types and response validation