# FullContact vs ZoomInfo API + MCP

> ZoomInfo scores 72.2 (BB) to FullContact's 51.8 (D) for lead enrichment. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/fullcontact-vs-zoominfo
- Markdown: https://www.anchorterminal.com/compare/fullcontact-vs-zoominfo.md (~2,750 tokens)
- Slim: https://www.anchorterminal.com/compare/fullcontact-vs-zoominfo.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/fullcontact-vs-zoominfo.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-14

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.

- FullContact: grade D, 51.8/100, rank #794 of 1076. Markdown https://www.anchorterminal.com/tools/fullcontact.md · JSON https://www.anchorterminal.com/api/v1/tools/fullcontact.json
- ZoomInfo API + MCP: grade BB, 72.2/100, rank #113 of 1076. Markdown https://www.anchorterminal.com/tools/zoominfo.md · JSON https://www.anchorterminal.com/api/v1/tools/zoominfo.json
- Best lead, contact and company data APIs for AI agents: https://www.anchorterminal.com/best/lead-data/index.md
- All 171 leads comparisons: https://www.anchorterminal.com/compare/lead-data/index.md

## Which one, for what

### FullContact (D)

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

Watch for: No public prices. Access starts with a sales conversation

### ZoomInfo API + MCP (BB)

Good 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

| Category | Weight | FullContact | ZoomInfo API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 62 | 87 | ZoomInfo API + MCP +25 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 70 | 84 | ZoomInfo API + MCP +14 |
| Agent ergonomics | 13% (16.2 this run) | 75 | 71 | FullContact +4 |
| Security & auth | 14% (17.5 this run) | 43 | 65 | ZoomInfo API + MCP +22 |
| Payments & pricing | 10% (12.5 this run) | 10 | 40 | ZoomInfo API + MCP +30 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 20 | 76 | ZoomInfo API + MCP +56 |
| Transparency & trust | 7% (8.8 this run) | 61 | 75 | ZoomInfo API + MCP +14 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **51.8 · D** | **72.2 · BB** | |

## Facts side by side

| Fact | FullContact | ZoomInfo API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | J2 Martech Corp. (FullContact, a Ziff Davis company) | ZoomInfo Technologies LLC |
| Hosted endpoint | `https://api.fullcontact.com/v3` | `https://api.zoominfo.com/gtm` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | API key | OAuth |
| Pricing | Paid | Freemium |
| x402 | no | no |
| Licence | Proprietary service under the FullContact Terms of Use and Services Agreement. Client libraries on GitHub | Proprietary service under ZoomInfo's Licence Terms and Conditions. The GTM CLI on GitHub is MIT |
| Tools exposed | 1 | 26 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-04-30 | 2026-10-02 |
| Terms last updated | 2025-03-21 | no date given |
| Privacy policy last updated | 2026-10-01 | 2025-10-13 |
| Customer content may train models | not found in the text | yes, with an opt-out |
| Terms restrict automated access | yes | yes |
| Terms restrict benchmarking | yes | yes |
| Terms or service can change without notice | yes | not found in the text |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | none | 534 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.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/fullcontact-vs-zoominfo.json, and with the fewest tokens: https://www.anchorterminal.com/compare/fullcontact-vs-zoominfo.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "fullcontact", "b": "zoominfo"}`. From a terminal: `anchor compare fullcontact zoominfo`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/fullcontact.json and https://www.anchorterminal.com/api/v1/tools/zoominfo.json

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