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.
By Argorant
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 works today
Each label shows how a path works today: a direct Argorant connection, a documented setup, a generic HTTP call, a CSV file, or something to check in your own account first.
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 offers a REST API. We found no official MCP server for it.
Step by step
- 1
Define one test 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 and note what was charged, how duplicates were handled, which fields came back, and whether each email was checked.
Expected result: A measured cost per usable, permitted output. - 4
Test governance
Revoke access, hit a small spending limit on purpose, and check the usage history.
Expected result: Evidence that the agent can be supervised and stopped.
Inspect the market before a paid action
The result count comes first. It lets you or your agent check that the filters describe the right market before any contact is revealed or exported.
Plans, credits, and access gates
| Provider or layer | What to know | Published price |
|---|---|---|
| Argorant | Plan credits or one-time credit packs with no subscription. Search, counts, and masked previews cost nothing. | From $0.035 per contact: 500 credits for $17.50, with larger one-time packs. No subscription, credits valid for 365 days. |
| 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. | See the vendor's current pricing. |
| 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. | See the vendor's current pricing. |
Best fit by job
| Option | Best for | Access | Cost model | Verdict |
|---|---|---|---|---|
| Argorant | Governed agent discovery and verified output | OAuth MCP, REST, CLI | Prepaid credits per contact found, or plan credits | Best when free exploration, a firm spending limit, and emails checked right before use 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 developers; no official MCP server found. |
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. Prices and plans change, so check the vendor's current page before you buy.
14 sources checked and datedShow sources
Continue the workflow
Prove the workflow
before you scale it.
Count and preview first, then approve verified contacts with a clear spending limit.
