Clearbit alternatives
The highest-scoring alternative to Clearbit is Apollo at 64/100 on the AgentReady, against 53/100 for Clearbit.
All scored in Company & Contact Data APIs.
What Apollo does that Clearbit does not
Apollo passes llms.txt published, pricing understandable, limits / constraints documented, self-service signup, free trial or free allowance, and Clearbit fails them. That is the whole of the gap between the two scores, so if none of those matter to your agent the ranking above overstates the difference.
Why people look for an alternative
Clearbit fails llms.txt published, llms-full.txt / full agent docs, structured api reference, openapi / spec quality, pricing understandable, request examples provided, response examples provided, errors and status codes documented, limits / constraints documented, self-service signup, no mandatory sales call, programmatic credential creation, free trial or free allowance, fast time to first request, copyable quickstart, structured, predictable output, machine-readable errors, retry behavior documented, idempotency support, rate-limit behavior predictable. Each one is a place an unattended run stops, which is usually what sends someone looking in the first place.
Where Clearbit loses the points
| Pillar | Clearbit | What it measures |
|---|---|---|
| Discover | 87 | Can an agent find it at all: sitemap, robots, structured data. |
| Understand | 23 | Is there a spec, an llms.txt, a machine-readable description. |
| Adopt | 50 | Signup, keys, SDKs, and whether a human has to be involved. |
| Operate | 53 | Rate-limit headers, errors, status, and behaviour under load. |
Clearbit is weakest on understand at 23/100. Without a spec an agent has to guess at endpoints, and it guesses wrong. If that is the part your agent depends on, take the ranking above seriously; if it is not, Clearbit may still be the right pick.
What an agent runs into with Clearbit
These are the findings from the last audit on 2026-08-22. Each one is a place unattended software stops, which is the practical reason to look at the list above.
- Make signup self-serve; an agent cannot sit through a sales call.
- Publish an OpenAPI spec so agents can generate a client.
- Flesh out the OpenAPI: paths, schemas, and descriptions.
- Document error responses as an enum in your OpenAPI.
- Let agents create API keys programmatically.
- Return X-RateLimit / Retry-After headers so agents pace themselves.
- Add /llms.txt so agents can find and read your capabilities.
- Publish an AGENTS.md or llms-full.txt with full agent context.
What this category actually supports
Across the 7 products scored in Company & Contact Data APIs, enrich a person is offered by 29%, find b2b contacts is offered by 29%, enrich a company is offered by 14%, research a company is offered by 14%. Anything under half is a gap you should expect to fill yourself whichever one you pick.
An agent can get this list directly: resolve("alternative to Clearbit") over the MCP server, or GET /v1/categories/data-enrichment.