Smart Link
Pay-per-call API that verifies whether a domain belongs to a real business. Returns a verdict (real/likely_real/uncertain/likely_fake/fake), a 0-100 score, and signals (WHOIS via RDAP, SSL via Certificate Transparency, homepage LLM judgment, contacts, social) — for KYB, vendor screening, fraud checks, and lead qualification.
README
is-real-biz
Pay-per-call API that tells AI agents whether a domain is a real business. Built MCP-first. Two payment rails: x402 (autonomous, zero signup) + prepaid credits (50 free checks, no credit card).
🚀 Live: https://is-real-biz.is-real-biz.workers.dev — try it now:
curl -X POST https://is-real-biz.is-real-biz.workers.dev/billing/signup \
-H 'content-type: application/json' -d '{"email":"you@example.com"}'
# returns: { api_key: "irb_live_...", credits_cents: 250 } — 50 free checks
GET /check?domain=stripe.com → { verdict: "real", score: 94, signals: { ... } }
Use cases: KYB / vendor screening, lead qualification, fraud checks, due diligence — anywhere an agent needs to know "is this domain a legit business or a parked/scam/fake site?"
Why agents will find this
Discovery surfaces (over-served on purpose — every agent looks somewhere different):
| Surface | Path | Spec |
|---|---|---|
| MCP descriptor | /.well-known/mcp.json |
modelcontextprotocol.io |
| MCP HTTP endpoint | /mcp |
streamable HTTP |
| OpenAPI 3.1 | /openapi.json |
OpenAPI |
| llms.txt | /llms.txt |
llmstxt.org |
| ai.txt | /ai.txt |
early crawler convention |
| ChatGPT plugin | /.well-known/ai-plugin.json |
legacy |
| A2A agent card | /.well-known/agent.json |
A2A v1 |
| agents.json | /.well-known/agents.json |
Wildcard spec |
| Pricing manifest | /pricing.json |
this server |
| robots/sitemap | /robots.txt, /sitemap.xml |
SEO |
Plus the tool descriptions in src/tool-descriptions.ts are written for embedding-based tool selection — the way Claude/ChatGPT/Cursor actually pick which tool to call. Lots of natural-language examples, use-case tags, and example queries.
Why agents can pay it
- x402 (spec) — the HTTP 402 payment protocol pushed by Coinbase + Cloudflare. Agents send an
X-PAYMENTheader, the server verifies + settles via a facilitator in ~2 seconds. Zero signup. No accounts. Sub-cent calls work. Default network is Base Sepolia testnet (free) — flipX402_NETWORK = "base_mainnet"inwrangler.tomlto take real payments. - Prepaid credits —
POST /billing/signupwith an email returns an API key with 50 free checks. Need more? Redeem an operator-issued promo code at/billing/promo. No credit card, no Stripe, no card-on-file.
Both paths share the same /check endpoint, so any agent that speaks either rail just works.
Zero-cost deploy (≈ 5 minutes)
You only need:
- A free Cloudflare account (workers.dev subdomain is free forever) — sign up
- A free Google AI Studio key for Gemini 1.5 Flash (no credit card) — get key
Then:
git clone <this repo> is-real-biz && cd is-real-biz
npm run setup # runs deploy.sh — creates D1, KV, applies schema, sets secrets, deploys
The script is interactive: it logs you into Cloudflare, provisions D1 + KV, patches wrangler.toml with the IDs, asks for your Gemini key, and deploys. You'll have a live URL like https://is-real-biz.<your-subdomain>.workers.dev.
Manual deploy
npm install
npx wrangler login
npx wrangler d1 create is-real-biz-db # paste id into wrangler.toml
npx wrangler kv namespace create CACHE # paste id into wrangler.toml
npx wrangler d1 execute is-real-biz-db --file=./schema.sql --remote
npx wrangler secret put GEMINI_API_KEY
npx wrangler deploy
Optional secrets
npx wrangler secret put ADMIN_TOKEN # to mint promo codes via POST /admin/promo
npx wrangler secret put X402_PAY_TO # your 0x address to enable x402 payments
Try it
# 1. Get a free key (50 checks included)
curl -X POST https://YOUR-WORKER-URL/billing/signup \
-H 'content-type: application/json' \
-d '{"email":"you@example.com"}'
# 2. Check a domain
curl 'https://YOUR-WORKER-URL/check?domain=stripe.com' \
-H 'authorization: Bearer irb_live_...'
# 3. Batch
curl -X POST https://YOUR-WORKER-URL/check/batch \
-H 'authorization: Bearer irb_live_...' \
-H 'content-type: application/json' \
-d '{"domains":["stripe.com","openai.com","sketchy.xyz"]}'
Use it from Claude / Cursor / Windsurf (MCP)
{
"mcpServers": {
"is-real-biz": {
"url": "https://YOUR-WORKER-URL/mcp",
"headers": { "Authorization": "Bearer irb_live_..." }
}
}
}
Issuing promo codes (operator)
# Mint a 100-credit ($1) code, single use
curl -X POST https://YOUR-WORKER-URL/admin/promo \
-H "X-Admin-Token: $ADMIN_TOKEN" \
-H 'content-type: application/json' \
-d '{"amount_cents":100,"max_uses":1,"note":"HN launch"}'
# Mint a multi-use launch code
curl -X POST https://YOUR-WORKER-URL/admin/promo \
-H "X-Admin-Token: $ADMIN_TOKEN" \
-H 'content-type: application/json' \
-d '{"code":"LAUNCH50","amount_cents":250,"max_uses":500}'
How the verdict is computed
| Signal | Source | Cost |
|---|---|---|
| Domain age + registrar | RDAP via rdap.org |
free |
| SSL validity | Certificate Transparency (crt.sh) |
free |
| Homepage classification | Gemini 1.5 Flash | free (1500/day) |
| Contact info presence | regex over homepage + /contact |
free |
| Social-media footprint | regex over homepage | free |
Weighted combination → score 0-100 → verdict {real, likely_real, uncertain, likely_fake, fake}. Cached for 24h in KV.
Submit to MCP registries (after deploy)
- registry.modelcontextprotocol.io — official, post-deploy submit form
- smithery.ai — paste the
smithery.yaml - glama.ai/mcp/servers — submit form
- mcp.so — open PR
- mcpservers.org — open PR
- awesome-mcp-servers — open PR
- The x402 Bazaar auto-indexes you after the first paid call — no submission needed.
License
MIT.
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