openunfurl

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.

• Endpoint: https://openunfurl.vercel.app/api/mcp
• Transport: Streamable HTTP, stateless (POST JSON-RPC 2.0, single application/json response — no sessions, no SSE)
• Exposes exactly one tool: unfurl — input { "url": "https://example.com" }, returns the same preview JSON as the REST endpoint (also as structuredContent)

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

• v0.1 parses static HTML only — no headless browser, no JS-rendered SPAs. If a site renders its <meta> tags client-side you get the static fallback.
• Best-effort per-instance IP rate limit — a soft abuse brake, not a guarantee (serverless instances are ephemeral and not shared).
• 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.

git clone https://github.com/SolvoHQ/openunfurl
cd openunfurl
npx vercel --prod

License

MIT — see LICENSE.