APIFold

Turn any REST API into an MCP server. No code required.

CI 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

1. Sign up at apifold.dev
2. Import a spec (URL, file upload, or browse the registry)
3. Copy the connection snippet into Claude Desktop or Cursor
4. 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