com.layercallPublished by layercall.comOfficial publisherv1.0.0Updated Oct 24, 2026
Score an IP, email, phone, domain or device for fraud in one call, with the signals behind it.
LayerCall is a remote fraud-scoring service that lets an assistant risk-score IPs, emails, phones, domains, devices and whole signups with verdicts.
Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.
Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.
Read https://sourceweft.com/mcp/com.layercall%2Ftrust-api/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.Add this to your client's mcpServers config.
{
"mcpServers": {
"layercall": {
"type": "http",
"url": "https://www.layercall.com/api/mcp",
"headers": {
"Authorization": "Bearer <YOUR_TOKEN>"
}
}
}
}[npm] [PyPI] [License] [Dependencies]
Official clients for LayerCall — score an IP, email, phone number, domain, or a whole signup for fraud in a single call.
Both clients have zero dependencies. A trust check sits on your signup path, which is the worst place in an application to introduce a dependency tree.
Get a free API key — 1,000 lookups a month, no card required, no daily cap.
Every endpoint returns the same shape: a 0–100 risk_score, an
allow | review | block verdict, and the signals behind it.
Prefer step-up over rejection. The review band starts where an ordinary
commercial VPN lands, and most VPN users are ordinary customers. Send them an
OTP or a 3-D Secure challenge instead of a refusal: a real user clears it in
seconds, an attacker cannot, and a false positive costs friction rather than a
customer. This is what Stripe Radar and Sift both converged on.
null means unknown, not "no". newly_registered is null when a TLD
publishes no RDAP (.de, .ru, .ac.uk among them), and mailbox_exists is
null when the mail provider does not answer honestly — Gmail and Yahoo accept
mail for addresses that do not exist. Treating either as a negative finding is
the specific mistake these fields exist to prevent.
Full reference: layercall.com/docs · OpenAPI 3.1: layercall.com/openapi.json
Test-mode keys return deterministic synthetic data, drawn from ranges
reserved for exactly this purpose — RFC 5737 addresses, example.com, the
555-01XX fiction block. Same shape and fields as production, so your assertions
are real ones. They never bill, never hit live data sources, and never write to
the shared reputation network.
Every fixture is documented, so you can assert on exact values rather than "did it return a number": layercall.com/docs/test-mode
LayerCall speaks the Model Context Protocol over Streamable HTTP, so Claude Code, Claude Desktop, ChatGPT, Cursor, VS Code, Windsurf and Zed can run a fraud check mid-conversation. There is nothing to install — it is a remote server, so you add a URL and your API key:
Seven tools are exposed: score_ip, verify_email, lookup_phone,
score_domain, score_device, verify_agent and score_user.
VS Code names the top-level key
servers, notmcpServers. That one difference is the usual reason a copied config silently does nothing.
Per-client setup: layercall.com/docs/mcp
Drop-in for the two places this usually goes. The middleware attaches
req.trust and leaves the decision to you:
There is deliberately no autoBlock: true. A one-line install that starts
rejecting people is the wrong default for a fraud tool — the failure is silent,
it lands on real customers, and you find out from a support ticket.
By default it only scores POST/PUT/PATCH, because a global app.use()
bills a lookup for every request including favicon.ico.
See node/src/express.ts and
node/src/next.ts (scoreRequest, withTrust).
Written for someone mid-incident rather than someone shopping. Each one ends with what a naive version gets wrong — including the parts that need no LayerCall at all.
MIT
Source: README.md at commit e192ad7
Score an IP address
Risk-score an IPv4 or IPv6 address. Detects commercial VPNs (naming the provider where its own published list confirms it), proxies, Tor exit nodes and datacenter hosting, and returns geolocation, ASN and a 0-100 risk score with an allow/review/block verdict.
iprequiredstrictnessVerify an email address
Check an email for syntax, MX records, disposable/throwaway providers, role accounts (info@, admin@), homograph lookalikes and domain age. Returns a 0-100 risk score and an allow/review/block verdict.
emailrequiredstrictnessValidate a phone number
Validate a phone number worldwide against its national numbering plan. Returns E.164, country, line type (mobile/fixed/VoIP/toll-free/premium) and a risk score. Works globally, not US-only.
phonerequiredcountrystrictnessScore a domain
Profile a domain: registration date from RDAP, registrar, MX/SPF/DMARC configuration, disposable-mail and risky-TLD detection. newly_registered is null when the age genuinely could not be determined — treat that as unknown, not as 'established'.
domainrequiredScore a device fingerprint
Judge a browser fingerprint from /fp.js: headless detection, automation frameworks (Selenium, Puppeteer, Playwright), timezone-versus-IP mismatch and repeat-device history. Note the ceiling honestly — the declared signals it relies on are the first thing stealth tooling patches, so a clean result is weaker evidence than a dirty one.
ipdevice_idrequiredVerify a signed AI agent (Web Bot Auth)
Cryptographically verify a Web Bot Auth signature (RFC 9421) — proof of WHICH agent is calling, not a guess from the user-agent. Returns verified true/false plus the agent's identity and declared purpose. This is the only check here that proves rather than infers, so it carries no score and no verdict: a verified assistant acting for a real user is usually welcome, a verified scraper usually is not, and that policy is the caller's. Pass the request the agent made to YOU — the signature covers its method, authority and path.
urlrequiredmethodheadersrequiredScore a whole signup
Score an entire signup in one call — any combination of IP, email, phone and domain — returning a single weighted risk score, a verdict, and the top contributing signals. A hard block on any component is never averaged away. This is the tool to use when judging a person rather than a value. Costs one lookup PER COMPONENT supplied, not one per call, so four identifiers cost four; the response reports the exact figure as billable_lookups, and cached components are refunded.
ipemailphonestrictnessphone_country100% of the applicable checks met
How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.
export LAYERCALL_API_KEY=tl_live_...npx layercall ip 8.8.8.8npx layercall email [email protected]npx layercall domain example.comnpx layercall user --ip 1.2.3.4 --email [email protected]{ "ip": "185.220.101.1", "risk_score": 60, "verdict": "review", "signals": { "is_vpn": true, "is_proxy": true, "is_datacenter": true, "is_tor": true, "recent_abuse": false }, "geo": { "country": "DE", "city": "Berlin", "asn": "AS60729" }, "vpn_provider": null}{ "mcpServers": { "layercall": { "url": "https://www.layercall.com/api/mcp", "headers": { "Authorization": "Bearer YOUR_API_KEY" } } }}import { layercall } from "layercall/express";
app.post("/signup", layercall(), (req, res) => { if (req.trust.verdict === "block") return res.status(403).json({ error: "..." }); if (req.trust.verdict === "review") flagForManualReview(req.trust); createAccount(req.body);});