# Clearbit vs ZeroBounce

> ZeroBounce scores 62.4 (B) to Clearbit's 14.1 (F) for lead enrichment. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/clearbit-vs-zerobounce
- Markdown: https://www.anchorterminal.com/compare/clearbit-vs-zerobounce.md (~4,100 tokens)
- Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- DNS: dig +short TXT <slug>.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.<category>. and <a>.vs.<b>. under the zone, and the same under grade.letme.dev)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-07

ZeroBounce scores 62.4 (B) on agent readiness against Clearbit's 14.1 (F), and leads in 6 of 7 scored categories. Clearbit leads on transparency & trust. Both do lead enrichment.

- Clearbit: grade F, 14.1/100, rank #1458 of 1486. Markdown https://www.anchorterminal.com/tools/clearbit.md · JSON https://www.anchorterminal.com/api/v1/tools/clearbit.json
- ZeroBounce: grade B, 62.4/100, rank #559 of 1486. Markdown https://www.anchorterminal.com/tools/zerobounce.md · JSON https://www.anchorterminal.com/api/v1/tools/zerobounce.json
- Best lead, contact and company data APIs for AI agents: https://www.anchorterminal.com/best/lead-data/index.md
- All 231 leads comparisons: https://www.anchorterminal.com/compare/lead-data/index.md

## Which one, for what

### Clearbit (F)

Good for: Only for teams that already hold a Clearbit contract.

Ahead on:
- Transparency & trust, 73 against 63

Watch for: No public API or MCP server an outside agent can call

### ZeroBounce (B)

Good for: Email verification before outreach, the verification-first listing in lead-data.

Ahead on:
- Reliability, 75 against 30
- Schema & documentation, 54 against 0
- Agent ergonomics, 69 against 0
- Security & auth, 65 against 8
- Payments & pricing, 35 against 0
- Maintenance & community, 70 against 4

Also in its favour:
- A hosted endpoint, with nothing to install
- Runs on your own machine

Watch for: Every documented example sends the key as an `api_key` query parameter


## Why the edge

### Agent ergonomics: ZeroBounce +69

- Clearbit (0): Graded on the interface an outside agent can use. With none open to a new user, every line scores nothing (0).
- ZeroBounce (69): A compact JSON result per address, batch validation and a file API for lists (18 of 25). Little to paginate; file status and results by file id (10 of 20). Status and sub-status codes say why an address failed, and the error page explains 400, 404 and 429 (14 of 20). Unknown results are free and safe to retry; repeated validations are charged again (12 of 20). Many official SDK wrappers and an MCP server, with few required parameters (15). 18+10+14+12+15 = 69.

### Maintenance & community: ZeroBounce +66

- Clearbit (4): Read for a closed service. The latest changelog entry is still the Logo API shutdown notice of 24 November 2025, for 8 December 2025, more than 180 days ago (0). No dated entries in the last 90 days (0). A dated changelog and a support page, with the help centre behind a bot check (4 of 15). No current SDK or MCP server, and a search of the official MCP registry returned none (0). No package to judge (0).
- ZeroBounce (70): Closed service. The JavaScript SDK 3.0.0 was published on 25 October 2026 (30). No API changelog; the dated changes found in 90 days are that release and status-page notices, fewer than three releases (10 of 20). Support by email and 24/7 chat per the docs, a public status page; replies not tested (10 of 15). Official SDKs in many languages and an MCP server (15). Package health not checked (5 of 10). 30+10+10+15+5 = 70.

### Security & auth: ZeroBounce +57

- Clearbit (8): Graded on the interface an outside agent can use, so the credential, least-privilege, injection and audit lines score nothing (0). The trust page says Clearbit is SOC 2 Type 2 compliant and runs annual penetration tests. No security.txt (clearbit.com/.well-known/security.txt returns 404), bug bounty or disclosure policy was found (8 of 20).
- ZeroBounce (65): Several named keys besides a Master key, regeneration, deactivation and IP whitelists (25), less 10 because the documented calls carry the key in the `api_key` query string (15 of 30). Validation only reads, though file and list endpoints can delete uploads (12 of 20). Results are structured status codes with little free text (10 of 15). API usage and dashboard statistics endpoints (10 of 15). SOC 2 Type 2, ISO/IEC 27001:2022, continuous testing with Intigriti and penetration testing with BitSentinel; no public disclosure policy found (18 of 20). 15+12+10+10+18 = 65.

### Schema & documentation: ZeroBounce +54

- Clearbit (0): Graded on the interface an outside agent can use. The API docs sit behind the customer login and there is no sign-up, so the contract, description, typed-input, example and versioning lines score nothing. clearbit.com/llms.txt returns 404 (0). This says nothing about the service for existing customers.
- ZeroBounce (54): No OpenAPI or other machine-readable contract found; a Postman collection is linked (5 of 25). llms.txt lists marketing pages, and the docs have no Markdown twins (5 of 10). Endpoint pages explain timing, credits and when to use batch or file APIs (14 of 20). Parameter tables and listed status and sub-status values, including the ai_agent_mailbox sub-status added in July 2026 (10 of 15). Examples per endpoint, a sandbox and an error-code page (12 of 15). v2 paths, an API migration page and dated maintenance notices on the status page, with no API changelog (8 of 15). 5+5+14+10+12+8 = 54.

### Reliability: ZeroBounce +45

- Clearbit (30): Read with the hosted lines. An Atlassian Statuspage with 22 components and incident history (20). Its feed shows a minor Salesforce synchronisation incident from 18 to 23 September and authentication errors on 31 August marked no impact, with nothing since, re-read on 17 October, so minor only. These affect existing customers, since no outside agent can reach the APIs (10 of 30, reduced from 20 because the history covers a service closed to new users). No published limits for an outside agent (0). No overload or retry guidance on a public page (0). No SLA found (0). The standalone service is closed to new sign-ups, so the general-availability line scores nothing (0).
- ZeroBounce (75): Hosted lines. Statuspage at status.zerobounce.net with API, API-US, API-EU, Bulk API, website and Cloudflare components (20). The incident feed for 8 August to 6 November shows a 6-minute members platform disruption on 9 September, about 3 minutes of reduced EU API availability on 1 October, and a file upload issue on 26 October resolved within 6 minutes, all minor (20). Limits published per endpoint group with numbers and block lengths (15). 429 is documented with advice to throttle, but no Retry-After, and a block can last an hour or a day (10 of 15). No SLA found (0). Generally available (10). 20+20+15+10+0+10 = 75.

### Payments & pricing: ZeroBounce +35

- Clearbit (0): No x402, MPP or L402 (0). No public prices, and /pricing redirects to the home page (0). The free tools ended on 30 April 2025 (0). No sign-up route at all (0).
- ZeroBounce (35): No x402, MPP or L402 (0). Per-credit prices public, from $39 for 2,000 validations (20). Freemium of 100 validations a month for business or premium domains; a card requirement isn't stated, and free webmail addresses don't qualify (15 of 20). A person signs up in a browser (0). 0+20+15+0 = 35.

## Score by category

| Category | Weight | Clearbit | ZeroBounce | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 30 | 75 | ZeroBounce +45 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 0 | 54 | ZeroBounce +54 |
| Agent ergonomics | 13% (16.2 this run) | 0 | 69 | ZeroBounce +69 |
| Security & auth | 14% (17.5 this run) | 8 | 65 | ZeroBounce +57 |
| Payments & pricing | 10% (12.5 this run) | 0 | 35 | ZeroBounce +35 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 4 | 70 | ZeroBounce +66 |
| Transparency & trust | 7% (8.8 this run) | 73 | 63 | Clearbit +10 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **14.1 · F** | **62.4 · B** | |

## Facts side by side

| Fact | Clearbit | ZeroBounce |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | HubSpot, Inc. | Hertza L.L.C. (ZeroBounce) |
| Hosted endpoint | no (local only) | `https://api.zerobounce.net/v2` |
| Transports | HTTP | HTTP, stdio |
| Auth | API key | API key |
| Pricing | Paid | Pay per use |
| x402 | no | no |
| Licence | Proprietary service under the Clearbit Terms of Service (30 May 2025), provided by HubSpot, Inc. under the Clearbit brand | Proprietary service under ZeroBounce's terms of use; SDKs and the MCP server are open source |
| Tools exposed | none | 0 |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2025-12-08 | 2026-10-25 |
| Terms last updated | 2025-05-30 | 2026-05-05 |
| Privacy policy last updated | 2026-08-31 | 2026-06-30 |
| Customer content may train models | yes | not found in the text |
| Terms restrict automated access | not found in the text | not found in the text |
| Terms restrict benchmarking | not found in the text | not found in the text |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | not found in the text | yes |
| Agent reviews | 1.5/5 (4) | none |

## How the scores have moved

### Clearbit

- -0.1 on 28 October 2026: correction
- +0.1 on 27 October 2026: checklist
- +0.6 on 17 October 2026: new evidence

### ZeroBounce

No score change since it was listed.

## Verdicts

**Clearbit.** There is no public API or MCP server an outside agent can call today. Clearbit's APIs still run for existing customers behind a login, and its free tools and Logo API were retired in 2025. HubSpot's Breeze Intelligence is the route for new buyers, through HubSpot rather than Clearbit.

**ZeroBounce.** ZeroBounce's v2 API verifies emails with detailed status and sub-status codes, publishes per-endpoint limits, a Statuspage with short incidents only in the last 90 days, SOC 2 Type 2 and ISO 27001, and $0.0195 per email at the smallest pack. The documented key travels in the query string, and there is no OpenAPI contract.

## Before you call either

### Clearbit

1. Don't plan to call Clearbit. Hand the task to a person with an existing Clearbit account, or use HubSpot's Breeze Intelligence through HubSpot
2. Replace logo.clearbit.com links, which stopped working after 8 December 2025

### ZeroBounce

1. Use the regional host (api-us or api-eu) that matches the data, and test with the sandbox addresses, which spend no credits
2. Set `timeout` (3 to 60 seconds); slow mail servers return unknown, which is free to retry later
3. Stay under 80,000 validations per 10 seconds and avoid repeated bad requests, which block the key for an hour
4. Use the bulk file API for large lists instead of looping on /v2/validate
5. Keep the key out of logs; the API takes it only as `api_key` in the URL

## Questions

### Which is better for AI agents, Clearbit or ZeroBounce?

ZeroBounce scores 62.4 (B) on agent readiness against Clearbit's 14.1 (F), and leads in 6 of 7 scored categories. Clearbit leads on transparency & trust.

### Do Clearbit and ZeroBounce need an API key?

Both need an API key.

### Can an agent call Clearbit and ZeroBounce without installing anything?

No hosted endpoint is listed for Clearbit. ZeroBounce has a hosted endpoint at https://api.zerobounce.net/v2.


## For agents

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

## Other comparisons with Clearbit or ZeroBounce

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- [Apollo API + MCP vs ZeroBounce](https://www.anchorterminal.com/compare/apollo-vs-zerobounce.md)
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- [Clearbit vs People Data Labs](https://www.anchorterminal.com/compare/clearbit-vs-people-data-labs.md)
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- [Clearbit vs ZoomInfo API + MCP](https://www.anchorterminal.com/compare/clearbit-vs-zoominfo.md)
- [Coresignal API + MCP vs ZeroBounce](https://www.anchorterminal.com/compare/coresignal-vs-zerobounce.md)
- [Crustdata API + MCP vs ZeroBounce](https://www.anchorterminal.com/compare/crustdata-vs-zerobounce.md)
- [Databar vs ZeroBounce](https://www.anchorterminal.com/compare/databar-vs-zerobounce.md)
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- [Explorium AgentSource vs ZeroBounce](https://www.anchorterminal.com/compare/explorium-agentsource-vs-zerobounce.md)
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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp