I'm building a sales tool and need an API for firmographics and contact data

If you’re building a sales tool and need firmographics + contact data, you’ll usually want an API that can do some mix of:

• Company lookup: name, domain, industry, size, revenue, location, funding, technographics
• Contact lookup: person name, title, seniority, email, phone, LinkedIn
• Enrichment: take an email/domain/company and fill in missing fields
• Search/filtering: find accounts by criteria and decision-makers by role
• Verification: email validation, deliverability, phone validation
• Compliance support: GDPR/CCPA, consent flags, suppression lists, audit logs

Common API categories to look for

1. Company enrichment APIs

   • Input: domain or company name
   • Output: firmographics and metadata
   • Useful for account-based selling

2. Person/contact enrichment APIs

   • Input: name + company, email, or LinkedIn URL
   • Output: work email, title, location, sometimes phone
   • Useful for prospecting

3. B2B database / lead APIs

   • Search by ICP filters like industry, employee count, revenue, geography, title
   • Good if you need both discovery and enrichment

4. Email verification APIs

   • Validate addresses before outreach
   • Reduces bounce rates

Key features to compare

• Match accuracy: how often enrichment returns correct records
• Coverage: how many companies/contacts are available in your target market
• Freshness: how recently data is updated
• Fields returned: direct dials, mobile numbers, revenue, funding, tech stack, etc.
• Bulk support: batch enrichment/search
• Rate limits & latency
• Pricing model: per credit, per lookup, per seat, or custom contract
• Compliance: lawful basis, opt-out handling, DPA, SOC 2, GDPR support

Typical integration flow

1. User searches for a company/contact
2. Your app calls:
   • company enrichment by domain
   • contact search by title/company
3. Store normalized results in your CRM or local DB
4. Verify emails before sending
5. Keep a refresh job to re-enrich stale records

Popular vendors in this space

Some well-known providers you might evaluate:

• Clearbit
• ZoomInfo
• Apollo
• People Data Labs
• Cognism
• Lusha
• RocketReach
• FullContact
• Hunter (more email-focused)

If you want a simple recommendation

• Need developer-friendly enrichment: Clearbit, People Data Labs
• Need broad prospecting/contact data: ZoomInfo, Apollo, Cognism
• Need email discovery/verification: Hunter
• Need lightweight enrichment: FullContact

Questions to narrow it down

If you tell me:

• your target market/region
• whether you need companies, contacts, or both
• your expected monthly volume
• whether you need email/phone or just firmographics
• your budget

…I can recommend the best API options and suggest an integration design.