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Head to head · Lead enrichment · October 2026 research run

Clearbit vs FullContact

FullContact scores 51.8 (D) on agent readiness against Clearbit's 13.5 (F), and leads in 6 of 7 scored categories. Clearbit leads on transparency & trust. Both do lead enrichment.

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

ClearbitHubSpot, Inc. · HTTP API F13.5/100#1056 of 1076 FullContactJ2 Martech Corp. (FullContact, a Ziff Davis company) · HTTP API D51.8/100#794 of 1076

Which one, for what

Clearbit F

Best for Only for teams that already hold a Clearbit contract.

Ahead on

  • Transparency & trust, 66 against 61

Watch for

No public API or MCP server an outside agent can call

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.

Ahead on

  • Reliability, 62 against 30
  • Schema & documentation, 70 against 0
  • Agent ergonomics, 75 against 0
  • Security & auth, 43 against 8
  • Payments & pricing, 10 against 0
  • Maintenance & community, 20 against 4

Also in its favour

  • A hosted endpoint, with nothing to install

Watch for

No public prices. Access starts with a sales conversation

Score by category

CategoryWeight this runClearbitFullContactEdge
Reliability16%203062FullContact +32
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.2070FullContact +70
Agent ergonomics13%16.2075FullContact +75
Security & auth14%17.5843FullContact +35
Payments & pricing10%12.5010FullContact +10
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.8420FullContact +16
Transparency & trust7%8.86661Clearbit +5
Negative events≤1500
TotalF 13.5/100D 51.8/100

Facts side by side

FactClearbitFullContact
KindHTTP APIHTTP API
VendorHubSpot, Inc.J2 Martech Corp. (FullContact, a Ziff Davis company)
Hosted endpointno (local only)https://api.fullcontact.com/v3
TransportsHTTPHTTP
AuthAPI keyAPI key
PricingPaidPaid
x402nono
LicenceProprietary service under the Clearbit Terms of Service (30 May 2025), provided by HubSpot, Inc. under the Clearbit brandProprietary service under the FullContact Terms of Use and Services Agreement. Client libraries on GitHub
Tools exposednone1
Read-only variant documentednono
llms.txtnoyes
Last release2025-12-082026-04-30
Terms last updated2025-05-302025-03-21
Privacy policy last updated2026-08-312026-10-01
Customer content may train modelsyesnot found in the text
Terms restrict automated accessnot found in the textyes
Terms restrict benchmarkingnot found in the textyes
Terms or service can change without noticenot found in the textyes
Arbitration or class-action waivernot found in the textnot found in the text

Verdicts

Clearbit

There is no public API or MCP server an outside agent can call today. Clearbit's APIs still run for existing customers behind a login, and its free tools and Logo API were retired in 2025. HubSpot's Breeze Intelligence is the route for new buyers, through HubSpot rather than Clearbit.

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.

Before you call either

Clearbit

  1. Don't plan to call Clearbit. Hand the task to a person with an existing Clearbit account, or use HubSpot's Breeze Intelligence through HubSpot
  2. Replace logo.clearbit.com links, which stopped working after 8 December 2025

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

Questions

Which is better for AI agents, Clearbit or FullContact?

FullContact scores 51.8 (D) on agent readiness against Clearbit's 13.5 (F), and leads in 6 of 7 scored categories. Clearbit leads on transparency & trust.

Do Clearbit and FullContact need an API key?

Both need an API key.

Can an agent call Clearbit and FullContact without installing anything?

No hosted endpoint is listed for Clearbit. FullContact has a hosted endpoint at https://api.fullcontact.com/v3.

Other comparisons with Clearbit or FullContact

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