1Lookup MCP¶

Contact verification without leaving the conversation. 1Lookup is a data verification platform whose hosted MCP server lets an agent validate a phone number, verify an email address, or look up an IP mid-workflow. OAuth 2.1 with dynamic client registration (RFC 7591) and PKCE means there is no API key to paste into a config file; tool calls spend the same universal credits as the 1Lookup REST API, one credit per lookup, and get_account is free.

Server type: Remote Streamable HTTP (hosted)
Endpoint: https://app.1lookup.io/api/mcp
Auth: OAuth 2.1 with DCR + PKCE (SSE disabled)
Tools: 5 (validate_phone, verify_email, ip_lookup, bulk_verify, get_account)
Registry: io.1lookup/1lookup (active)
Plans: paid, every plan starts with a 7-day free trial

Why This Matters for Operators¶

Lead hygiene and compliance are the same workflow: a bad list wastes outbound effort, and dialing numbers on a Do-Not-Call list is a fine. 1Lookup's tools answer the three questions that gate outbound work: is this phone real, mobile or landline, and DNC-listed? Is this email deliverable, or disposable? Is this visitor a proxy or VPN? bulk_verify handles up to 50 values per call, which is the shape real list-cleaning takes.

Tools & Capabilities¶

Tool	What it does
`validate_phone`	Line type, carrier, and DNC status for a phone number
`verify_email`	Email deliverability plus disposable and role-based flags
`ip_lookup`	IP geolocation with proxy, VPN, and Tor detection
`bulk_verify`	Up to 50 values per call
`get_account`	Remaining plan credits (free, spends no credits)

Installation¶

{
  "mcpServers": {
    "1lookup": {
      "type": "http",
      "url": "https://app.1lookup.io/api/mcp"
    }
  }
}

Connect with one URL; the OAuth 2.1 flow handles registration and consent.

Configuration¶

OAuth 2.1 with PKCE, no API key or secret in the config file. Requires a paid plan; tool calls spend credits at one credit per lookup. The endpoint returns 401 on anonymous initialize, which is the expected live-and-gated posture.

Business Relevance¶

Outbound compliance: DNC checks before dialing campaigns.
List hygiene: strip disposables and role addresses before sends.
Fraud triage: proxy and VPN detection on inbound leads and logins.
Agent-native ops: verification inside the CRM workflow instead of a separate tab.

Integration with CorpusIQ¶

1Lookup's verification results pair with CorpusIQ connectors for the CRM side: enrich and flag contacts in HubSpot or Close as they are verified, log DNC status in Airtable for campaign compliance, and trigger follow-up automations from the verification outcome.

Limitations¶

Paid plan required after the 7-day trial; credits are consumed per lookup.
OAuth-only auth; headless environments need to complete the browser flow once.
Verification data reflects the vendor's coverage and freshness, not a legal certification of compliance.