Hunter.io API
Email finder and verification API for finding professional email addresses by domain or name, with email validation and deliverability checking.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
API key auth. GDPR considerations for email data — use for B2B prospecting only, not personal email harvesting. Rate limits prevent bulk harvesting. SOC2 not documented.
⚡ Reliability
Best When
You need to find and verify professional email addresses for B2B outreach or lead enrichment in agent workflows.
Avoid When
You operate in GDPR-strict environments where finding emails without consent may violate regulations, or need non-email contact data.
Use Cases
- • Finding professional email addresses for outreach agents
- • Verifying email deliverability before sending campaigns
- • Discovering all emails at a domain for company mapping
- • Enriching contact records with verified email addresses
- • Building lead lists from company domains
Not For
- • Consumer email lookups
- • Phone number or social media enrichment
- • Jurisdictions with strict data privacy laws that restrict email finding
Interface
Authentication
API key as query parameter (api_key). Simple key-based access with no scopes.
Pricing
Free tier is suitable for light testing. Monthly search quota resets. Unused searches roll over on paid plans.
Agent Metadata
Known Gotchas
- ⚠ Monthly quota resets on billing date, not calendar month - track usage carefully
- ⚠ Domain Search returns up to 100 results per call - pagination required for large companies
- ⚠ Email verification results include disposable/accept-all flags that agents should check before use
- ⚠ GDPR considerations: finding emails of EU individuals may require legal basis
- ⚠ Confidence scores below 75 indicate uncertain matches - agents should threshold these
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for Hunter.io API.
Scores are editorial opinions as of 2026-03-06.