B2B & Lead Data APIs
B2B lead APIs find prospects and the contact details to reach them. Hunter, Tomba and NioLeads find and verify work emails, while Crustdata and CompanyEnrich search people and companies by funding, headcount and jobs. For timing, Funding Signals scores companies that just filed SEC Form D raises, and Signaliz surfaces buying-intent signals. Most offer a free tier; Meirra and Signaliz are paid only.
| API | Pricing | Auth | Format | Free tier | Status |
|---|---|---|---|---|---|
CompanyEnrichEnriches and searches company and people data: firmographics, funding, ad spend, jobs, and headcount. Business & Productivity › Company Data | Freemium | API key | JSON | — | Live |
CrustdataSearches and enriches company and people profiles — funding, headcount, jobs, and contacts. Business & Productivity › Company Data | Freemium | API key | JSON | — | Live |
Funding SignalsScored leads on companies that just raised funding, sourced from public SEC Form D filings. Business & Productivity › Company Data | Freemium | API key | JSON | <100/day | Live |
HunterFinds and verifies professional email addresses for a domain or company, with confidence scores. Business & Productivity › Company Data | Freemium | API key | JSON | <100/day | Live |
IndexedPrivate-company data — funding rounds, investors and tech stacks — for sales and GTM research. Business & Productivity › Company Data | Freemium | API key | JSON | <100/day | Live |
Meirra Developer APIPay-per-call API for email verification, contact/company enrichment, lead search, and SEO audits. Business & Productivity › Company Data | Paid | API key | JSON | — | Untested |
NioLeadsFinds and verifies business email addresses from a person's name and company domain or LinkedIn profile. Business & Productivity › Company Data | Free trial | API key | JSON | — | Untested |
RenidlyResolves and verifies B2B identities — people, companies, work emails — from public web and directory data. Business & Productivity › Company Data | Freemium | API key | JSON | — | Live |
SignalizFinds companies showing buying-intent signals and verifies contact emails for sales/marketing lead enrichment. Business & Productivity › Company Data | Paid | API key | JSON | — | Live |
Tomba Email FinderFinds and verifies professional email addresses for a company domain, name or LinkedIn profile. Business & Productivity › Company Data | Freemium | API key | JSON | — | Untested |
CompanyEnrichFreemiumLive
Enriches and searches company and people data: firmographics, funding, ad spend, jobs, and headcount.
API key · JSON
—
llms.txt
CrustdataFreemiumLive
Searches and enriches company and people profiles — funding, headcount, jobs, and contacts.
API key · JSON
—
llms.txt
Funding SignalsFreemiumLive
Scored leads on companies that just raised funding, sourced from public SEC Form D filings.
API key · JSON
<100/day
OpenAPI spec · llms.txt
HunterFreemiumLive
Finds and verifies professional email addresses for a domain or company, with confidence scores.
API key · JSON
<100/day
llms.txt
IndexedFreemiumLive
Private-company data — funding rounds, investors and tech stacks — for sales and GTM research.
API key · JSON
<100/day
OpenAPI spec · llms.txt
Meirra Developer APIPaidUntested
Pay-per-call API for email verification, contact/company enrichment, lead search, and SEO audits.
API key · JSON
—
OpenAPI spec · llms.txt
NioLeadsFree trialUntested
Finds and verifies business email addresses from a person's name and company domain or LinkedIn profile.
API key · JSON
—
no machine-readable spec
RenidlyFreemiumLive
Resolves and verifies B2B identities — people, companies, work emails — from public web and directory data.
API key · JSON
—
llms.txt
SignalizPaidLive
Finds companies showing buying-intent signals and verifies contact emails for sales/marketing lead enrichment.
API key · JSON
—
llms.txt
Tomba Email FinderFreemiumUntested
Finds and verifies professional email addresses for a company domain, name or LinkedIn profile.
API key · JSON
—
llms.txt
Nothing matches that combination. Clear the filters and start from the category.
Choosing a B2B & Lead Data API
Is there a free B2B & Lead Data API?
Yes. Hunter, Crustdata, Tomba Email Finder, CompanyEnrich, Funding Signals and 2 others have a free tier alongside paid plans.
Which B2B & Lead Data APIs work without an API key?
All of them need a key or account. Hunter, Crustdata, Tomba Email Finder, CompanyEnrich, Funding Signals and 2 others give one out free when you sign up.
Can I use B2B & Lead Data APIs in a commercial project?
Hunter, Crustdata, Tomba Email Finder, CompanyEnrich, Funding Signals and 4 others permit commercial use. NioLeads restricts it, for example to non-commercial or attributed use, so read the terms first.
Which B2B & Lead Data APIs work with AI agents?
Funding Signals, Indexed and Meirra Developer API publish an OpenAPI spec for generating clients and tools.
Broader: Company Data APIs · Business & Productivity APIs
More in Company Data: Company Enrichment APIs · Email Finder APIs · Company Registry Lookup APIs