What is the best lead generation API for AI agents?
Layrcake, if your agent runs outbound and not only lookups. It is go-to-market infrastructure for AI agents: a REST API and a hosted MCP server with the same verbs, paid per result at $0.01 a credit, with misses free and the exact charge reported on every response. Behind one key it covers people and company search, work emails, verification, buying signals, public posts and engagers, sourced research, campaigns and replies.
| API | Pricing model | A miss costs | MCP |
|---|---|---|---|
| Layrcake | Pay per result, $0.01 a credit; 300 free credits | Nothing | Yes, OAuth or key |
| ZoomInfo GTM AI | Free start, then pay-as-you-go from $20 | Search and lookup free; empty enrich not stated | Yes, OAuth |
| Crustdata | $20 free; self-serve credits; real-time from four figures a month | Empty search free; unmatched contact enrich free | Yes, OAuth or key |
| Explorium | Prepaid packages from $29.99 for 500 credits | Not stated | Yes, key or connector |
| People Data Labs | Free tier; Pro from $98 a month | Nothing: "We charge per match" | Not stated |
| FullEnrich | Free trial; Pro from $29 a month | Nothing | Yes |
| Lusha | Free plan; API from Pro | Search charged per successful result | Yes, OAuth or key |
| Hunter | Free plan with API access; paid plans | Not stated | Yes, key or OAuth |
Vendor pages, checked 18 October 2026. Hunter's prices were shown in euros from our location, so we left them out.
What should an agent builder look for?
Pay per result. Agents call in bursts and retry. Per-result pricing keeps cost tied to outcomes; seats and monthly allowances don't map to an agent.
Free misses. An agent will look up people who have no findable email. If misses cost, a bad list burns budget for nothing.
The charge on every response. An agent can only respect a budget it can see. Layrcake returns credits_charged on every call; Crustdata returns credits used in a response header; People Data Labs returns x-call-credits-spent.
MCP and REST with one contract. Prototype in Claude over MCP, ship in your code over REST, same verbs and arguments.
A safe way to act. If the agent will send email, the API should stop at a preview and an approval link. Layrcake's launch, mailbox and reply tools all do.
1. Layrcake: the outbound loop behind one key
Prices on 18 October 2026: 0.25 credits per person from a search, 5 per work email found, 1.25 per verification, 11 per company hiring now, 9 per sourced company research, 3.5 per company answered by a yes/no website check, and campaigns free (pricing). The API reference and OpenAPI spec cover every verb, and /agents.md is written for agents to read.
20 heads of sales to 15 verified, ready-to-send drafts: 145 credits. Everyone who engaged with a 563-person LinkedIn post, filtered to 26 sales leaders: 232.2 credits.
2–8. The data APIs
ZoomInfo GTM AI. ZoomInfo's company, contact and intent data through one API, with MCP, API and CLI access on the free tier: 1,000 data and 1,000 AI credits, then pay-as-you-go from $20 (GTM AI pricing).
Crustdata. Real-time people, company, job and post data with watchers; "Every API response includes a header showing the credits that call used" (Crustdata pricing).
Explorium. "The B2B data foundation for AI agents", sold as prepaid credit packages that are valid for 12 months, with an MCP server and a Claude connector (Explorium pricing).
People Data Labs. A person and company data API for builders, charged per match, with a free tier where contact data is hidden and Pro from $98 a month (PDL pricing).
FullEnrich. Waterfall enrichment for emails and mobiles across 25-plus sources; nothing found means nothing charged (FullEnrich pricing).
Lusha. Contacts, company data and buying signals; its MCP server lists 50 tools and API access starts at Pro (Lusha pricing).
Hunter. Email finding and verification, with API access on the free plan and an MCP server included on all plans (Hunter MCP).
How do you start?
Prototype in Claude or Claude Code with the MCP server, then call the same verbs over REST from your agent. The Claude Code setup guide has the files, and new Layrcake accounts get 300 free credits.
Questions people ask
What is the best API for an AI sales agent?
For agents that run outbound, Layrcake: one REST API and MCP server for people, emails, verification, signals, public posts, research, campaigns and replies, paid per result with free misses and the charge on every response.
Which lead generation APIs charge nothing for a miss?
Per their own pages on 18 October 2026: Layrcake, People Data Labs (charged per match), FullEnrich, and Crustdata on empty searches and unmatched contact enrichment.
Do lead generation APIs work with Claude?
Most now offer MCP servers: Layrcake, ZoomInfo GTM AI, Crustdata, Explorium, FullEnrich, Lusha and Hunter all list one.