web2mcp

web2mcp

Turn any website or REST API into MCP tools — one tiny Cloudflare Worker, zero dependencies.

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GitHub's 665 REST endpoints → 2 MCP tools, ~147,000 tokens of tool definitions → ~300 (catalog mode)

Every AI agent (Claude, ChatGPT, Cursor, your own bots…) now speaks the Model Context Protocol. But most websites and apps don't. web2mcp is the glue: describe an HTTP API in a few lines of config and it instantly becomes an MCP tool that any agent can call — hosted for free on Cloudflare's edge.

 Claude / Cursor / any MCP client

│ MCP (Streamable HTTP, JSON-RPC) ▼ ┌──────────────────────────┐ │ web2mcp (CF Worker) │ connectors/*.js or CONNECTORS_JSON └──────────────────────────┘ │ │ │ Wikipedia GitHub any REST API / web page …

Try it now

A public demo is running at https://web2mcp.cwei59969.workers.dev (tool list) with the MCP endpoint at:

https://web2mcp.cwei59969.workers.dev/mcp

Paste it into any client that supports remote MCP servers, or:

curl -s https://web2mcp.cwei59969.workers.dev/mcp -H 'content-type: application/json' \

-d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"weather_forecast","arguments":{"latitude":35.68,"longitude":139.69}}}'

The demo is rate-limited by the free plan and has reader_read disabled. Deploy your own for real use.

Why

• Config, not code. A connector is a plain object: base URL, path, query, params. No SDK to learn.
• Zero runtime dependencies. ~500 lines of readable JavaScript. Audit it in 10 minutes.
• Token-friendly output. pick and fields trim giant JSON responses down to what the model needs.
• Free hosting. Runs on the Cloudflare Workers free plan. Deploy in one click.
• Safe by default. Requests are locked to each connector's host, arguments are type-checked, secrets stay server-side, optional bearer auth.
• OpenAPI import. Convert any OpenAPI 3 spec into a connector with one command.

Built-in connectors (no API keys)

Deploy your own in one click

Click Deploy to Cloudflare above. Cloudflare copies this repo into your GitHub account, asks for an AUTH_TOKEN (any long random string, e.g. openssl rand -hex 32), then builds and deploys it. A minute later your server is live at https://web2mcp. .workers.dev/mcp, and every push to your copy redeploys it. The free Workers plan is enough.

Quick start

git clone https://github.com/charleswei118/web2mcp && cd web2mcp

npm test # unit tests, no install needed (Node 20+) npm run smoke # calls every built-in tool against the real APIs npx wrangler dev # local server at http://localhost:8787/mcp npx wrangler deploy # your own https://web2mcp. .workers.dev/mcp

Optional: protect your endpoint

npx wrangler secret put AUTH_TOKEN

Connect an AI client

Claude Desktop / Cursor / Windsurf (via mcp-remote):

{

"mcpServers": { "web2mcp": { "command": "npx", "args": ["-y", "mcp-remote", "https://web2mcp. .workers.dev/mcp", "--header", "Authorization: Bearer ${WEB2MCP_TOKEN}"], "env": { "WEB2MCP_TOKEN": "your-token" } } } }

Run locally over stdio (no Cloudflare account needed; same connectors):

{

"mcpServers": { "web2mcp": { "command": "npx", "args": ["-y", "github:charleswei118/web2mcp"], "env": { "ENABLED_CONNECTORS": "wikipedia,hackernews,weather" } } } }

Or with Docker: docker build -t web2mcp . && docker run -i --rm web2mcp. Environment variables work the same as Worker bindings (ENABLED_CONNECTORS, CONNECTORS_JSON, MAX_OUTPUT_CHARS, TOOL_MODE=catalog).

Clients that support remote MCP servers natively (Claude.ai custom connectors, ChatGPT connectors, the OpenAI Responses API, Cloudflare AI Playground…) can use the URL directly. Test with the official inspector:

npx @modelcontextprotocol/inspector   # transport: Streamable HTTP, URL: .../mcp

Write a connector

Create connectors/myapi.js and add it to connectors/index.js:

export default {

name: "openlibrary", // tool names become openlibrary_ description: "Search books on Open Library.", baseUrl: "https://openlibrary.org", headers: { /* "authorization": "Bearer ${MY_API_KEY}" */ }, tools: [ { name: "search", description: "Search books by title or author.", method: "GET", // GET | POST | PUT | PATCH | DELETE path: "/search.json", // "{arg}" in the path is URL-encoded query: { q: "{query}", limit: "{limit}" }, params: { query: { type: "string", required: true, description: "Title or author" }, limit: { type: "integer", minimum: 1, maximum: 20, default: 5 }, }, pick: "docs", // dotted path into the JSON response fields: ["title", "author=author_name", "year=first_publish_year"], }, ], };

Template rules:

No-code option: put connectors in the CONNECTORS_JSON secret (a JSON array of the same objects) and they appear without touching the code. Use ENABLED_CONNECTORS="wikipedia,weather" to expose only some.

From an OpenAPI spec

node scripts/openapi2connector.js https://petstore3.swagger.io/api/v3/openapi.json petstore --only GET > connectors/petstore.js

Catalog mode: 665 endpoints, 2 tools

Exposing every endpoint as its own tool floods the model's context. In catalog mode web2mcp exposes just two tools:

• search_api — find operations by keywords; returns their names and argument schemas
• call_api — run one operation by name with an arguments object

Measured with GitHub's full REST OpenAPI spec (GET operations only, converted with scripts/openapi2connector.js):

Turn it on per request with /mcp?mode=catalog, or for the whole deployment with the variable TOOL_MODE = "catalog" (?mode=tools switches back). Try it on the demo: https://web2mcp.cwei59969.workers.dev/mcp?mode=catalog.

Endpoints

Supported MCP methods: initialize, ping, tools/list, tools/call, plus empty resources/list and prompts/list. Protocol versions 2025-06-18, 2025-03-26, 2024-11-05.

Roadmap

• Catalog mode (search_api + call_api) — v0.2
• Load OpenAPI specs at runtime from a URL
• One-click “Deploy to Cloudflare” — v0.2
• HTML scraping connectors (CSS selectors via HTMLRewriter)
• Per-tool rate limits and KV caching
• OAuth for connectors that need user accounts
• Connector registry: share connectors as JSON files
• Agent-to-agent (A2A) chat rooms on Durable Objects

PRs with new connectors are very welcome — see CONTRIBUTING.md.

Responsible use

Only connect APIs and sites you are allowed to use. Respect each service's terms, robots rules and rate limits, and keep credentials in Worker secrets.

License

MIT

If web2mcp saves you time, please ⭐ the repo — it helps others find it.