Best B2B Data APIs for AI Agents
A task-based comparison of B2B data APIs for agents, covering REST, MCP, authentication, preview controls, paid reveals, licensing, and the cost of a usable contact rather than a nominal credit.
Reviewed and updated August 20, 2026 by Argorant
Argorant is the strongest fit when an agent must size and preview a market before spending, then reveal verified contacts behind a prepaid ceiling. Apollo, ZoomInfo, Hunter, Lusha, Prospeo, Seamless.AI, LeadIQ, and People Data Labs can fit narrower workflows, but their credit units, client support, and embedding rights differ enough that they should be tested on one identical job.
What is actually supported
These labels separate a code-backed direct path from documentation, generic HTTP, CSV, and workflows that still require an end-to-end test. A marketing logo alone does not count as support.
Argorant remote MCP
MCPOAuth MCP at https://mcp.argorant.com/mcp with discovery, count, preview, reveal, list, and export tools.
Argorant REST and CLI
RESTBearer-key access for deterministic applications and terminal-driven agents.
Third-party MCP
DocumentedApollo, ZoomInfo, Hunter, Lusha, Prospeo, Seamless.AI, and LeadIQ document MCP or connector access with provider-specific entitlements.
API-only option
RESTPeople Data Labs is evaluated as an API source, not as a proven official MCP server.
Reproducible workflow
- 1
Define one benchmark job
Use the same ICP, geography, seniority, and ten-contact output for every provider.
Expected result: A comparison that measures equivalent work rather than incomparable credit labels. - 2
Explore without buying
Run count, search, or masked preview where supported and record result depth and latency.
Expected result: The agent proves the market exists before it performs a charged action. - 3
Reveal and validate
Reveal ten work emails, record charged units, duplicate handling, fields, and verification status.
Expected result: A measured cost per usable, permitted output. - 4
Test governance
Revoke credentials, exceed a small spend ceiling, and inspect audit or credit logs.
Expected result: Evidence that the agent can be supervised and stopped.
Inspect the market before a paid action
The result count is the first control point. It lets an operator or agent confirm that the interpreted filters produce a plausible market before revealing or exporting contact data.
Plans, credits, and access gates
| Provider or layer | Restriction to model | Published price where verified |
|---|---|---|
| Argorant | Plan credits or a no-subscription prepaid wallet; search, count, and masked preview are the non-spend layer. | $0.035 per contact through 500, 1,000, or 3,000-contact wallet top-ups. |
| Hunter | MCP is included on all plans, but normal request limits and credits still apply. | Free includes 50 monthly credits; Starter is $49 monthly or $34/month as the annual equivalent. |
| Prospeo | Search pages, email enrichment, and email plus mobile consume different units. | Free includes 100 monthly credits; Starter is $49 monthly or $37/month as the annual equivalent. |
| LeadIQ | Its Claude connector requires an active paid subscription and spends ordinary LeadIQ credits. | Confirm in the current account or quote. |
| People Data Labs | Free testing obfuscates contact fields; production fields require a paid plan. | Pro begins at $98/month for 350 monthly records. |
| Apollo and ZoomInfo | API, MCP, external-product, and resale rights are plan or contract specific; obtain written confirmation. | Confirm in the current account or quote. |
Best fit by job
| Option | Best for | Access | Cost model | Verdict |
|---|---|---|---|---|
| Argorant | Governed agent discovery and verified output | OAuth MCP, REST, CLI | Prepaid successful contact output or plan credits | Best when free exploration, a hard spend ceiling, and point-of-use verification matter. |
| Apollo | Broad prospecting and workflow actions | Hosted OAuth MCP and API | Normal plan credits by action | Strong breadth; verify external-product rights and action-level charging. |
| ZoomInfo | Enterprise data, research, and signals | OAuth MCP and contracted products | Quote-led contract | Powerful enterprise option; commercial and API rights are not publicly uniform. |
| Hunter | Domain and email workflows | Remote MCP and API | Plan credits | Clear documented access with a narrower job than a full company-and-person database. |
| People Data Labs | API-first data engineering | REST API | Monthly record allowance | Useful for builders, but not an identified official MCP route in this review. |
Verification gates
- Run count, five-row preview, ten-contact reveal, and export through every ranked account.
- Record tool names, OAuth scopes, charged units, no-result behavior, rate limits, and CSV fields.
- Confirm all pricing and annual-equivalent labels on publication day.
Claims this guide does not make
- Do not say every listed provider has the same MCP depth or client support.
- Do not equate a search request, verified email, mobile number, export, and CRM write as one comparable credit.
- Do not claim ZoomInfo or Apollo embedding and resale rights without written contract evidence.
Frequently asked questions
What makes a B2B data API agent-ready?
It needs narrow documented tools, scoped authentication, a non-spend discovery stage, predictable charging, revocation, and machine-readable error states. A REST endpoint alone does not provide those controls.
Can an agent reveal contacts without approval?
Technically that depends on the client and credential scope. A production workflow should impose a prepaid ceiling or explicit approval before reveal and export, even when the provider does not force one.
Sources reviewed
Official product, developer, pricing, and policy pages reviewed on August 20, 2026. Test-gated behavior remains labelled until a live end-to-end run proves the current account and plan path.
14 sources checked and datedShow sources
Continue the workflow
Prove the workflow
before you scale it.
Count and preview first, then authorize verified output behind a visible spend boundary.
