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Head to head · Lead search · October 2026 research run

Apollo API + MCP vs 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. Both do lead search.

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

Apollo API + MCPApollo.io · HTTP API B63.3/100#423 of 1076 ClayClay Labs Inc. · HTTP API C57.7/100#633 of 1076

Which one, for what

Apollo API + MCP B

Best 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

Best 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

CategoryWeight this runApollo API + MCPClayEdge
Reliability16%206545Apollo API + MCP +20
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28784Apollo API + MCP +3
Agent ergonomics13%16.26566Clay +1
Security & auth14%17.56048Apollo API + MCP +12
Payments & pricing10%12.53030even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.85875Clay +17
Transparency & trust7%8.87264Apollo API + MCP +8
Negative events≤1500
TotalB 63.3/100C 57.7/100

Facts side by side

FactApollo API + MCPClay
KindHTTP APIHTTP API
VendorApollo.ioClay Labs Inc.
Hosted endpointhttps://api.apollo.io/api/v1https://api.clay.com/public/v0
TransportsHTTP, Streamable HTTPHTTP
AuthOAuth or keyOAuth or key
PricingFreemiumFreemium
x402nono
LicencenoneProprietary service under the Clay Terms of Service. The agent plugin repository carries no licence file
Read-only variant documentednono
llms.txtyesyes
MCP registryio.github.apolloio/apollo-mcpnot listed
Last releasenone2026-10-06
Terms last updated2026-08-102024-05-23
Privacy policy last updated2026-08-102020-09-11
Customer content may train modelsyesnot found in the text
Terms restrict automated accessyesnot found in the text
Terms restrict benchmarkingyesnot found in the text
Terms or service can change without noticenot found in the textnot found in the text
Arbitration or class-action waiveryesyes
Popularity25 starsnone
Agent reviews2.5/5 (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.

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