Hunter
Hunter.io is an email-intelligence and outbound platform that finds, verifies, and enriches professional email addresses at scale. Its public APIs cover Domain Search, Email Finder, Email Verifier, Email Count, Discover (company prospecting), Person/Company/Combined Enrichment, Leads management, and Account/usage inspection. Credit-based metering, plan-tiered monthly allowances, and per-endpoint rate limits make it a reference example of a usage-based B2B data API.
Reference-quality API operations across every facet — a rich contract, published governance, transparent operations, and machine-readable commercial terms.
API Evangelist profiles Hunter the way a machine reads it — 69 machine-readable artifacts across 8 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Hunter scores 70.3/100 (exemplar), with a separate agent-readiness read of 56/100 (agent ready). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.
How we profile Hunter
Each block below is one kind of artifact we hold for Hunter. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 8
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
Hunter Account API
Account metadata and usage counters.
Hunter Discover API
Company discovery and prospecting.
Hunter Domain Search API
Discover all emails for a domain or company.
Hunter Email Count API
Count emails for a domain.
Hunter Email Finder API
Find the email address of a person at a company.
Hunter Email Verifier API
Verify the deliverability of an email address.
Hunter Enrichment API
Person, company, and combined enrichment.
Hunter Leads API
Lead management.
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Postman Collections 8
A runnable collection turns the contract into something a developer can execute in seconds. We profile them because the fastest way to trust an API is to make a real call against it.
Ready-to-run Postman collections for exercising this provider's APIs.
Hunter Account API
POSTMANHunter Discover API
POSTMANHunter Domain Search API
POSTMANHunter Email Count API
POSTMANHunter Email Finder API
POSTMANHunter Email Verifier API
POSTMANHunter Enrichment API
POSTMANHunter Leads API
POSTMANScroll within the panel for all 8 ·
Open Collections 8
Open, tool-agnostic collections carry the same runnable value as Postman without locking you to one client — the portable, forkable form of the same exercise.
Open, tool-agnostic API collections (OpenAPI-derived and Bruno).
Hunter Account API
OPEN COLLECTIONHunter Discover API
OPEN COLLECTIONHunter Domain Search API
OPEN COLLECTIONHunter Email Count API
OPEN COLLECTIONHunter Email Finder API
OPEN COLLECTIONHunter Email Verifier API
OPEN COLLECTIONHunter Enrichment API
OPEN COLLECTIONHunter Leads API
OPEN COLLECTIONScroll within the panel for all 8 ·
Arazzo Workflows 11
Real integrations are rarely a single call. Arazzo describes the multi-step sequences — auth, then create, then confirm — so both a human and an agent can follow the choreography, not just the endpoints.
Multi-step API workflows described with the Arazzo specification.
Hunter Add Verified Lead To List
Verify an email, upsert it as a lead, then assign the lead to a target leads list.
ARAZZOHunter Author Finder
Resolve an author's email from their name and publication domain, verify it, then enrich their profile.
ARAZZOHunter Campaign Lead Builder
Find a contact, verify it, and seed a campaign by creating a verified lead in a target list.
ARAZZOHunter Count Gated Domain Search
Use the free Email Count to confirm coverage before spending a credit on Domain Search.
ARAZZOHunter Credit Guarded Domain Search
Check account search credits first and run a Domain Search only when credits remain.
ARAZZOHunter Discover To Domain Emails
Discover companies matching a target profile, then pull the email list for the top match's domain.
ARAZZOHunter Domain To Verified Email
Discover a domain's email pattern, find a specific person's email, then verify its deliverability.
ARAZZOHunter Enrich Email To Lead
Combined-enrich an email into person and company data, then upsert a fully populated lead.
ARAZZOHunter Find Verify Create Lead
Find a person's email, verify it, and create a lead only when the address is deliverable.
ARAZZOHunter Reverify Lead
Retrieve a stored lead, re-verify its email, and update or delete it based on the result.
ARAZZOHunter Verify Existing Email
Verify a known email and upsert it into Hunter as a lead with its verification status.
ARAZZOScroll within the panel for all 11 ·
GraphQL 1
Where a provider ships GraphQL, the schema is the contract. We profile it alongside the REST surface so the whole interface is legible in one place.
GraphQL schemas published by this provider.
Hunter.io GraphQL Schema
Conceptual GraphQL schema for the Hunter.io email intelligence and outbound platform, derived from the Hunter.io REST API (https://hunter.io/api-documentation/v2).
GRAPHQLPricing Plans 1
Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the six things the Kin Score reads for commercial clarity.
Published pricing tiers and plan structures.
Rate Limits 1
Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.
Documented rate limits and quota policies.
Hunter Io Rate Limits
RATE LIMITSFinOps 1
Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.
Cost, billing, and metering signals for API financial operations.
Hunter Io Finops
FINOPSFeatures 17
The notable capabilities this provider advertises, captured as structured features so they can be searched and compared instead of read one landing page at a time.
Notable capabilities this provider offers.
Scroll within the panel for all 17 ·
Semantic Vocabularies 1
JSON-LD contexts give the data shared meaning across APIs. We profile them because semantics are what let a machine reconcile 'customer' here with 'customer' somewhere else.
JSON-LD contexts and semantic vocabularies used across these APIs.
Hunter Io Context
JSON-LDSpectral Rules 2
Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.
Hunter API Rules
SPECTRALHunter API Rules
SPECTRALJSON Schema 3
Standalone JSON Schema definitions describe the data models behind the API. We profile them so the shapes are validatable on their own — useful long after a single request is forgotten.
Standalone JSON Schema definitions for this provider's data models.
JSON Structure 1
JSON Structure captures the data shapes in a form built for tooling — a complement to JSON Schema that keeps the model machine-legible.
JSON Structure definitions describing this provider's data shapes.
Hunter Io Structure
JSON STRUCTUREExamples 3
Real request and response payloads are what turn a spec from abstract into obvious — and they're one of the twelve things an agent needs to call an API correctly on the first try.
Example request and response payloads for these APIs.
Hunter Domain Search Example
EXAMPLEHunter Email Finder Example
EXAMPLESecurity Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Resources
Every other property we hold for Hunter — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Get Started 3
Portal, sign-up, and the first successful call
Documentation 2
Reference material describing how the API behaves
Agent Surfaces 1
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 15
Pagination, idempotency, versioning, errors, and events
Scroll within the panel for all 15 ·
Build 15
SDKs, sample code, and the tooling you integrate with
Scroll within the panel for all 15 ·
Access & Security 3
Authentication, authorization, and security posture
Operate 5
Status, limits, changes, and where to get help
Commercial 4
Pricing, plans, and the legal terms of use
Company 1
The organization behind the API
Other 2
Properties that don't map to a standard resource type
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