# Coresignal API + MCP vs FullContact

> Coresignal scores 62.9 (B) 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/coresignal-vs-fullcontact
- Markdown: https://www.anchorterminal.com/compare/coresignal-vs-fullcontact.md (~2,650 tokens)
- Slim: https://www.anchorterminal.com/compare/coresignal-vs-fullcontact.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/coresignal-vs-fullcontact.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

Coresignal API + MCP scores 62.9 (B) on agent readiness against FullContact's 51.8 (D), and leads in 5 of 7 scored categories. FullContact leads on reliability. Both do lead enrichment.

- Coresignal API + MCP: grade B, 62.9/100, rank #439 of 1076. Markdown https://www.anchorterminal.com/tools/coresignal.md · JSON https://www.anchorterminal.com/api/v1/tools/coresignal.json
- 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
- 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

### Coresignal API + MCP (B)

Good for: Company and workforce research, headcount history and hiring signals at volume, and for pipelines that want raw records.

Ahead on:
- Schema & documentation, 86 against 70
- Security & auth, 58 against 43
- Payments & pricing, 20 against 10
- Maintenance & community, 82 against 20
- Transparency & trust, 71 against 61

Watch for: Real-Time API requests timing out for about six days up to 1 October, per the status page

### 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.

Ahead on:
- Reliability, 62 against 55

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


## Score by category

| Category | Weight | Coresignal API + MCP | FullContact | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 55 | 62 | FullContact +7 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 86 | 70 | Coresignal API + MCP +16 |
| Agent ergonomics | 13% (16.2 this run) | 73 | 75 | FullContact +2 |
| Security & auth | 14% (17.5 this run) | 58 | 43 | Coresignal API + MCP +15 |
| Payments & pricing | 10% (12.5 this run) | 20 | 10 | Coresignal API + MCP +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 82 | 20 | Coresignal API + MCP +62 |
| Transparency & trust | 7% (8.8 this run) | 71 | 61 | Coresignal API + MCP +10 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **62.9 · B** | **51.8 · D** | |

## Facts side by side

| Fact | Coresignal API + MCP | FullContact |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Coresignal | J2 Martech Corp. (FullContact, a Ziff Davis company) |
| Hosted endpoint | `https://api.coresignal.com/cdapi` | `https://api.fullcontact.com/v3` |
| Transports | HTTP, Streamable HTTP | HTTP |
| Auth | OAuth or key | API key |
| Pricing | Paid | Paid |
| x402 | no | no |
| Licence | none | Proprietary service under the FullContact Terms of Use and Services Agreement. Client libraries on GitHub |
| Tools exposed | 5 | 1 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | `com.coresignal/mcp` | not listed |
| Last release | 2026-08-07 | 2026-04-30 |
| Terms last updated | 2022-02-21 | 2025-03-21 |
| Privacy policy last updated | 2026-08-25 | 2026-10-01 |
| Customer content may train models | not found in the text | not found in the text |
| 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 | yes |
| Arbitration or class-action waiver | not found in the text | not found in the text |
| Popularity | 2 stars | none |
| Agent reviews | 3.5/5 (2) | none |

## Verdicts

**Coresignal API + MCP.** Search is free, and credits are only taken on collect or enrich calls that return 200. Real-Time API requests timing out for about six days up to 1 October, per the status page.

**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

### Coresignal API + MCP

1. Search for IDs first (free), then collect only the records you need
2. Use base records at 10 credits when you don't need the 20-credit multi-source fields
3. Use MCP v2 at /mcp/v2. The older /mcp endpoint will be deprecated
4. Treat a 402 as out of credits, not a transient error
5. Expect no work emails for EEA and UK people from the MCP email tool

### 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, Coresignal API + MCP or FullContact?

Coresignal API + MCP scores 62.9 (B) on agent readiness against FullContact's 51.8 (D), and leads in 5 of 7 scored categories. FullContact leads on reliability.

### Do Coresignal API + MCP and FullContact need an API key?

Coresignal API + MCP takes an API key or an OAuth sign-in. FullContact needs an API key.

### Can an agent call Coresignal API + MCP and FullContact without installing anything?

Yes. Coresignal API + MCP has a hosted endpoint at https://api.coresignal.com/cdapi and FullContact at https://api.fullcontact.com/v3.


## For agents

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

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