# Apollo API + MCP vs Clay

> Apollo scores 63.3 (B) 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/apollo-vs-clay
- Markdown: https://www.anchorterminal.com/compare/apollo-vs-clay.md (~2,450 tokens)
- Slim: https://www.anchorterminal.com/compare/apollo-vs-clay.min.md (~630 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/apollo-vs-clay.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

Apollo API + MCP scores 63.3 (B) on agent readiness against Clay's 57.7 (C), and leads in 4 of 7 scored categories. Clay leads on maintenance & community. Both do lead search.

- Apollo API + MCP: grade B, 63.3/100, rank #423 of 1076. Markdown https://www.anchorterminal.com/tools/apollo.md · JSON https://www.anchorterminal.com/api/v1/tools/apollo.json
- 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
- 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

### Apollo API + MCP (B)

Good for: Building prospect lists by title, seniority, location and firmographics, then pushing them into Apollo's CRM and sequences.

Ahead on:
- Reliability, 65 against 45
- Security & auth, 60 against 48
- Transparency & trust, 72 against 64

Watch for: Headless MCP use needs a master key that reaches every endpoint

### Clay (C)

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

Ahead on:
- Maintenance & community, 75 against 58

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


## Score by category

| Category | Weight | Apollo API + MCP | Clay | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 65 | 45 | Apollo API + MCP +20 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 87 | 84 | Apollo API + MCP +3 |
| Agent ergonomics | 13% (16.2 this run) | 65 | 66 | Clay +1 |
| Security & auth | 14% (17.5 this run) | 60 | 48 | Apollo API + MCP +12 |
| Payments & pricing | 10% (12.5 this run) | 30 | 30 | even |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 58 | 75 | Clay +17 |
| Transparency & trust | 7% (8.8 this run) | 72 | 64 | Apollo API + MCP +8 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **63.3 · B** | **57.7 · C** | |

## Facts side by side

| Fact | Apollo API + MCP | Clay |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Apollo.io | Clay Labs Inc. |
| Hosted endpoint | `https://api.apollo.io/api/v1` | `https://api.clay.com/public/v0` |
| Transports | HTTP, Streamable HTTP | HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | none | Proprietary service under the Clay Terms of Service. The agent plugin repository carries no licence file |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | `io.github.apolloio/apollo-mcp` | not listed |
| Last release | none | 2026-10-06 |
| Terms last updated | 2026-08-10 | 2024-05-23 |
| Privacy policy last updated | 2026-08-10 | 2020-09-11 |
| Customer content may train models | yes | not found in the text |
| Terms restrict automated access | yes | not found in the text |
| Terms restrict benchmarking | yes | not found in the text |
| 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 | 25 stars | none |
| Agent reviews | 2.5/5 (2) | none |

## Verdicts

**Apollo API + MCP.** People search costs 0 credits, up to 100 records a page and 50,000 a query. Headless MCP use needs a master key that reaches every endpoint.

**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.

## Before you call either

### Apollo API + MCP

1. Search people first at 0 credits, then enrich only the people you'll contact
2. Branch on `error_details.code` and wait `retry_after_seconds` from the suggestions after a 429
3. Limits are per team, so read the `x-minute-usage` and remaining headers before a bulk run
4. Use a scoped key with only the endpoints the job needs. A master key reaches everything
5. Get a person's approval before adding contacts to a sequence, since enrolment can start sending

### 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

## Questions

### Which is better for AI agents, Apollo API + MCP or Clay?

Apollo API + MCP scores 63.3 (B) on agent readiness against Clay's 57.7 (C), and leads in 4 of 7 scored categories. Clay leads on maintenance & community.

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

Both take an API key or an OAuth sign-in.

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

Yes. Apollo API + MCP has a hosted endpoint at https://api.apollo.io/api/v1 and Clay at https://api.clay.com/public/v0.


## For agents

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

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