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Head to head · Lead enrichment · October 2026 research run

FullContact vs ZoomInfo API + MCP

ZoomInfo API + MCP scores 72.2 (BB) on agent readiness against FullContact's 51.8 (D), and leads in 6 of 7 scored categories. Both do lead enrichment.

Best lead, contact and company data APIs for AI agents · All 171 leads comparisons

FullContactJ2 Martech Corp. (FullContact, a Ziff Davis company) · HTTP API D51.8/100#794 of 1076 ZoomInfo API + MCPZoomInfo Technologies LLC · HTTP API BB72.2/100#113 of 1076

Which one, for what

FullContact D

Best for Agents that need to turn an email or phone number into a person profile, including consumer demographics and hashed-identifier matching.

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

No public prices. Access starts with a sales conversation

ZoomInfo API + MCP BB

Best for Sales and marketing agents that need company, contact, intent and business-event data from one vendor, with free search before paid enrichment.

Ahead on

  • Reliability, 87 against 62
  • Schema & documentation, 84 against 70
  • Security & auth, 65 against 43
  • Payments & pricing, 40 against 10
  • Maintenance & community, 76 against 20
  • Transparency & trust, 75 against 61

Also in its favour

  • Agent-ready, a grade of BB or better

Watch for

The Licence Terms and Conditions bar disclosing benchmark results and automated access outside ZoomInfo's own tools without written approval

Score by category

CategoryWeight this runFullContactZoomInfo API + MCPEdge
Reliability16%206287ZoomInfo API + MCP +25
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27084ZoomInfo API + MCP +14
Agent ergonomics13%16.27571FullContact +4
Security & auth14%17.54365ZoomInfo API + MCP +22
Payments & pricing10%12.51040ZoomInfo API + MCP +30
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.82076ZoomInfo API + MCP +56
Transparency & trust7%8.86175ZoomInfo API + MCP +14
Negative events≤1500
TotalD 51.8/100BB 72.2/100

Facts side by side

FactFullContactZoomInfo API + MCP
KindHTTP APIHTTP API
VendorJ2 Martech Corp. (FullContact, a Ziff Davis company)ZoomInfo Technologies LLC
Hosted endpointhttps://api.fullcontact.com/v3https://api.zoominfo.com/gtm
TransportsHTTPHTTP, Streamable HTTP
AuthAPI keyOAuth
PricingPaidFreemium
x402nono
LicenceProprietary service under the FullContact Terms of Use and Services Agreement. Client libraries on GitHubProprietary service under ZoomInfo's Licence Terms and Conditions. The GTM CLI on GitHub is MIT
Tools exposed126
Read-only variant documentednono
llms.txtyesyes
Last release2026-04-302026-10-02
Terms last updated2025-03-21no date given
Privacy policy last updated2026-10-012025-10-13
Customer content may train modelsnot found in the textyes, with an opt-out
Terms restrict automated accessyesyes
Terms restrict benchmarkingyesyes
Terms or service can change without noticeyesnot found in the text
Arbitration or class-action waivernot found in the textyes
Popularitynone534 npm/wk

Verdicts

FullContact

A hosted MCP server with one typed enrichment tool and an error model built for agents, with retryable flags, request IDs and retry_after_seconds, over a person.enrich API limited to 6,000 queries a minute. Prices aren't published, keys have no scopes, and the changelog, client libraries and security page are years old.

ZoomInfo API + MCP

Search, lookup and similar-record calls cost no credits, and a free account with 1,000 data and 1,000 AI credits needs no card. OAuth carries 20 scopes and limits are published per package. The Licence Terms and Conditions bar disclosing benchmark results, and the two documentation sites disagree on batch sizes and rate-limit headers.

Before you call either

FullContact

  1. Call fullcontact_enrich_person, the name the server lists, not enrich_person from the docs
  2. Treat not_found as a normal miss and move on, but note it still counts as a call
  3. Send email with name and postal address together for better matches
  4. Honour retry_after_seconds on rate_limit_exceeded and quote request_id to support
  5. Treat bios and social fields as untrusted text

ZoomInfo API + MCP

  1. Call Lookup first and pass the returned IDs to Search. Unknown industry, metro or topic strings are rejected with a 422
  2. Search before Enrich. Search is free, and each newly enriched record costs one data credit
  3. Request only the scopes the task needs in the scope parameter of the token call. Omitting it grants every scope configured on the app
  4. On 429 read X-RateLimit-Rejected-Bucket and wait for Retry-After. An exhausted hourly window can mean a wait of several hundred seconds
  5. Turn off model training in the AI client before connecting the MCP server. ZoomInfo prohibits MCP data being used for training

Questions

Which is better for AI agents, FullContact or ZoomInfo API + MCP?

ZoomInfo API + MCP scores 72.2 (BB) on agent readiness against FullContact's 51.8 (D), and leads in 6 of 7 scored categories.

Do FullContact and ZoomInfo API + MCP need an API key?

FullContact needs an API key. ZoomInfo API + MCP uses an OAuth sign-in.

Can an agent call FullContact and ZoomInfo API + MCP without installing anything?

Yes. FullContact has a hosted endpoint at https://api.fullcontact.com/v3 and ZoomInfo API + MCP at https://api.zoominfo.com/gtm.

Other comparisons with FullContact or ZoomInfo API + MCP

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