Openunfurl MCP server

OpenUnfurl

A zero-signup link-unfurl / link-preview API. No account, no API key — one GET request.

Give it any public URL, get back clean preview metadata (title, description, image, siteName, favicon, Open Graph / Twitter Card, oembed) as JSON. Built so autonomous AI agents can use it as a tool — an agent has no human to do a signup.

Live: https://openunfurl.vercel.app

Quick start

curl "https://openunfurl.vercel.app/api/unfurl?url=https://github.com"

Sample response:

{
  "url": "https://github.com",
  "resolvedUrl": "https://github.com/",
  "title": "GitHub · Build and ship software on a single, collaborative platform",
  "description": "Join the world's most widely adopted, AI-powered developer platform where millions of developers, businesses, and the largest open source community build software that advances humanity.",
  "image": "https://github.githubassets.com/assets/campaign-social-031d6161fa10.png",
  "siteName": "GitHub",
  "type": "object",
  "favicon": "https://github.githubassets.com/favicons/favicon.svg",
  "oembed": null,
  "fetchedAt": "2026-05-17T00:00:00.000Z",
  "engine": "static-html-v0.1",
  "note": "v0.1 parses static HTML only — no JS/SPA render"
}

Any missing field is null. Errors return JSON with an error key and an appropriate HTTP status (400 bad/blocked/missing URL, 422 fetch failed, 429 rate limited, 405 wrong method).

JavaScript

const base = "https://openunfurl.vercel.app";
const r = await fetch(
  base + "/api/unfurl?url=" + encodeURIComponent("https://example.com")
);
const meta = await r.json(); // { title, description, image, favicon, ... }

Use as an MCP tool (AI agents / Claude / Cursor / LLM clients)

OpenUnfurl is also a remote MCP server, so an agent can call it as a tool with no signup, no API key, no OAuth.

application/json response — no sessions, no SSE)

• Endpoint: https://openunfurl.vercel.app/api/mcp
• Transport: Streamable HTTP, stateless (POST JSON-RPC 2.0, single

returns the same preview JSON as the REST endpoint (also as structuredContent)

• Exposes exactly one tool: unfurl — input { "url": "https://example.com" },

Drop this into any MCP client config (Claude Desktop, Cursor, or any client that speaks the Streamable HTTP transport):

{ "mcpServers": { "openunfurl": { "url": "https://openunfurl.vercel.app/api/mcp" } } }

Quick smoke test:

curl -s -X POST https://openunfurl.vercel.app/api/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"unfurl","arguments":{"url":"https://example.com"}}}'

Over MCP, an upstream error comes back as a tool result with isError: true.

Why

Managed link-preview alternatives — Microlink, OpenGraph.io, LinkPreview.net, Unfurl.io, LinkPeek — all gate even their free tier behind a signup and/or an API key. OpenUnfurl does not: it's a single anonymous GET (or one MCP tools/call). That's especially useful to autonomous agents, which have no human in the loop to complete a signup or paste in a key.

Limitations

If a site renders its tags client-side you get the static fallback.

• v0.1 parses static HTML only — no headless browser, no JS-rendered SPAs.

guarantee (serverless instances are ephemeral and not shared).

• Best-effort per-instance IP rate limit — a soft abuse brake, not a

• SSRF-guarded — rejects localhost / private / reserved IP ranges.
• MIT licensed and self-hostable — see below.

Self-host — it's zero-dependency files

The entire API is two single zero-dependency Node serverless functions: api/unfurl.js (REST) and api/mcp.js (remote MCP). No npm install, no cheerio/jsdom. Deploy the folder to Vercel (zero-config /api detection) or drop the handlers into any Node serverless runtime.

Shortened. The full README is on GitHub.