# Clay vs ZoomInfo API + MCP

> ZoomInfo scores 72.2 (BB) to Clay's 57.7 (C) for lead search. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/clay-vs-zoominfo
- Markdown: https://www.anchorterminal.com/compare/clay-vs-zoominfo.md (~2,650 tokens)
- Slim: https://www.anchorterminal.com/compare/clay-vs-zoominfo.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/clay-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 Clay's 57.7 (C), and leads in 6 of 7 scored categories. Both do lead search.

- Clay: grade C, 57.7/100, rank #633 of 1076. Markdown https://www.anchorterminal.com/tools/clay.md · JSON https://www.anchorterminal.com/api/v1/tools/clay.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

### Clay (C)

Good for: Agents building prospect lists and enriching contacts or accounts through many providers at once.

Watch for: API keys carry no scopes and act with the user's workspace access

### 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 45
- Agent ergonomics, 71 against 66
- Security & auth, 65 against 48
- Payments & pricing, 40 against 30
- Transparency & trust, 75 against 64

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 | Clay | ZoomInfo API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 45 | 87 | ZoomInfo API + MCP +42 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 84 | 84 | even |
| Agent ergonomics | 13% (16.2 this run) | 66 | 71 | ZoomInfo API + MCP +5 |
| Security & auth | 14% (17.5 this run) | 48 | 65 | ZoomInfo API + MCP +17 |
| Payments & pricing | 10% (12.5 this run) | 30 | 40 | ZoomInfo API + MCP +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 75 | 76 | ZoomInfo API + MCP +1 |
| Transparency & trust | 7% (8.8 this run) | 64 | 75 | ZoomInfo API + MCP +11 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **57.7 · C** | **72.2 · BB** | |

## Facts side by side

| Fact | Clay | ZoomInfo API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Clay Labs Inc. | ZoomInfo Technologies LLC |
| Hosted endpoint | `https://api.clay.com/public/v0` | `https://api.zoominfo.com/gtm` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | OAuth or key | OAuth |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Proprietary service under the Clay Terms of Service. The agent plugin repository carries no licence file | Proprietary service under ZoomInfo's Licence Terms and Conditions. The GTM CLI on GitHub is MIT |
| Tools exposed | none | 26 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-06 | 2026-10-02 |
| Terms last updated | 2024-05-23 | no date given |
| Privacy policy last updated | 2020-09-11 | 2025-10-13 |
| Customer content may train models | not found in the text | yes, with an opt-out |
| Terms restrict automated access | not found in the text | yes |
| Terms restrict benchmarking | not found in the text | yes |
| Terms or service can change without notice | not found in the text | not found in the text |
| Arbitration or class-action waiver | yes | yes |
| Popularity | none | 534 npm/wk |

## Verdicts

**Clay.** A documented Public API with an OpenAPI spec, llms.txt and plan-capped search, plus a JSON-first CLI released several times a fortnight, give agents Clay's people search and multi-provider enrichment. Keys have no scopes, the Claude Code plugin auto-approves most CLI calls, and the privacy policy dates from 2020.

**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

### Clay

1. Fetch GET /search/query-mode/reference before writing a search query
2. Poll routine results until a terminal 200, since 202 means still running
3. Expect HTTP 402 when a plan's search cap is hit, and tell the user the reset date
4. Check GET /credits/balance before large batch runs
5. Ask the user before enabling the plugin's auto-approve hook in a shared workspace

### 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, Clay or ZoomInfo API + MCP?

ZoomInfo API + MCP scores 72.2 (BB) on agent readiness against Clay's 57.7 (C), and leads in 6 of 7 scored categories.

### Do Clay and ZoomInfo API + MCP need an API key?

Clay takes an API key or an OAuth sign-in. ZoomInfo API + MCP uses an OAuth sign-in.

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

Yes. Clay has a hosted endpoint at https://api.clay.com/public/v0 and ZoomInfo API + MCP at https://api.zoominfo.com/gtm.


## For agents

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

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