License Transformer npm Node

APIFold reads an OpenAPI 3.x or Swagger 2.x specification and generates a live, production-ready MCP server endpoint. AI agents — Claude, Cursor, Copilot, or any MCP-compatible client — can connect immediately. Tool calls execute real HTTP requests to real upstream APIs with securely stored credentials. No stubs, no mocks, no glue code.

Quick Start

CLI (fastest)

npx apifold serve ./your-openapi-spec.yaml --base-url https://api.example.com

One command. Your spec becomes a running MCP server with SSE transport on localhost:3000. Connect Claude or Cursor immediately.

From the API Registry

npx apifold serve --registry stripe --base-url https://api.stripe.com

Ships with 8 pre-configured API specs: Stripe, GitHub, Slack, HubSpot, Twilio, OpenAI, Notion, and Petstore.

Hosted Platform

Sign up at apifold.dev
Import a spec (URL, file upload, or browse the registry)
Copy the connection snippet into Claude Desktop or Cursor
Your MCP server is live with a unique endpoint URL

Features

OpenAPI 3.x + Swagger 2.0 — auto-converts Swagger 2.0 specs transparently
CLI tool — npx apifold serve for zero-config local MCP servers
API registry — one-click deploy from 8 curated API specs
OAuth 2.0 — Authorization Code (PKCE), Client Credentials, 8 provider presets, auto token refresh
Access profiles — tool-level permissions (Read Only / Read-Write / Full Access)
Analytics — call volume, latency percentiles, error breakdown, usage quotas
Custom domains — use mcp.yourcompany.com with DNS verification
Unique endpoint IDs — cryptographic, unguessable URLs per server
SSE + Streamable HTTP — both MCP transport modes supported
Vault encryption — AES-256-GCM for all stored credentials
SSRF protection — DNS pinning, redirect blocking, private IP rejection

CLI

npm install -g @apifold/cli

Command	Description
`apifold serve <spec>`	Start an MCP server from an OpenAPI spec
`apifold serve --registry stripe`	Start from a registry spec
`apifold transform <spec>`	Output MCP tool definitions as JSON
`apifold validate <spec>`	Parse-only validation with warnings
`apifold init [spec]`	Generate an `apifold.config.yaml` template

Config file

# apifold.config.yaml
spec: ./openapi/stripe.yaml
port: 3001
transport: sse
baseUrl: https://api.stripe.com
auth:
  type: bearer
  token: ${STRIPE_API_KEY}
filters:
  tags: [payments, customers]
  methods: [get, post]

Self-Hosting

Development

git clone https://github.com/Work90210/APIFold.git
cd APIFold
pnpm install
cp .env.example .env
docker compose -f infra/docker-compose.dev.yml up -d
pnpm dev

Open http://localhost:3000 to access the dashboard.

Production

cp .env.example .env
# Edit .env with your production values
docker compose -f infra/docker-compose.yml up -d

Using the Transformer Library

The core conversion logic is a standalone MIT-licensed npm package:

npm install @apifold/transformer

import { parseSpec, transformSpec, autoConvert } from "@apifold/transformer";

// Auto-convert Swagger 2.0 if needed
const { spec } = await autoConvert(rawSpec);

// Parse and transform
const parsed = parseSpec({ spec });
const { tools } = transformSpec({ spec: parsed.spec });
// tools = MCPToolDefinition[] ready for any MCP server

Architecture

graph LR
    Spec["OpenAPI / Swagger\nSpec"] --> Transformer

    subgraph MT["APIFold"]
        Transformer["Transformer\n(MIT lib)"]
        Transformer --> Runtime["Runtime\nExpress + SSE"]
        Web["Web App\nNext.js"] --> DB["Postgres 16\nRedis 7"]
        Runtime --> DB
        CLI["CLI Tool\nnpx apifold"]
        Registry["API Registry\n8 specs"]
    end

    Runtime --> Upstream["Upstream API\n(Stripe, GitHub, etc.)"]
    Agent["AI Agent\nClaude, Cursor,\nCopilot, etc."] -- "MCP / SSE" --> Runtime

Component	Path	Description
Transformer	`packages/transformer`	OpenAPI to MCP conversion. Pure functions. MIT licensed.
Runtime	`apps/runtime`	Express MCP server with SSE/HTTP, OAuth token refresh, access profiles.
Web App	`apps/web`	Next.js dashboard. Import specs, manage credentials, analytics, custom domains.
CLI	`apps/cli`	Standalone CLI tool. `npx apifold serve` for local MCP servers.
Registry	`packages/registry`	Curated catalog of 8 validated API specs with one-click deploy.
Types	`packages/types`	Shared TypeScript type definitions.
UI	`packages/ui`	Design system and component library.

Available Commands

Command	Description
`pnpm dev`	Start all services with hot-reload
`pnpm build`	Build all packages
`pnpm test`	Run tests
`pnpm lint`	Lint all packages
`pnpm typecheck`	Type-check all packages
`pnpm format`	Format all files with Prettier
`pnpm db:migrate`	Run database migrations
`pnpm db:studio`	Open Drizzle Studio

Contributing

All code contributions must go through a pull request and be approved before merging. See the contribution guide.

Want to add an API to the registry? See packages/registry/CONTRIBUTING.md.

Security

For security issues, please refer to our security policy. Do not post security vulnerabilities as public GitHub issues.

License

@apifold/transformer — MIT License
Everything else — GNU Affero General Public License v3.0

APIFold