Unif API Docs

Check if a domain is a free email provider

Classify a bare domain as `free`, `business`, or `invalid` against 4,768 free email provider domains (the list HubSpot forms block with "Block free email providers", snapshot 2026-10-10). Matching is exact: subdomains of a listed domain are not treated as free. A pasted address or website URL is reduced to its domain first. Costs 0 credits.

Pricing — Free

This endpoint returns billing metadata with zero credits charged.

GET
/email/domains/{domain}

Authorization

bearerAuth
AuthorizationBearer <token>

UnifAPI API key. Provider credentials are managed by UnifAPI.

In: header

Path Parameters

domain*string

Domain to classify, e.g. outlook.com. A full address or website URL is accepted; its domain is used.

Length1 <= length <= 512

Header Parameters

Unifapi-Version?"2026-07-01"

Pin the API version an integration was built against (date-based, e.g. 2026-07-01). Omit to use the current version. Public URL paths stay stable and unversioned; breaking changes ship under a new dated version and are announced with Deprecation and Sunset response headers. The served version is echoed in every response's Unifapi-Version header. Policy: https://unifapi.com/versioning.md

Default"2026-07-01"

Value in

  • "2026-07-01"

Response Body

application/json

application/json

application/json

application/json

application/json

application/json

application/json

application/json

application/json

curl -X GET "https://example.com/email/domains/string"
{  "request_id": "string",  "data": {    "input": "string",    "domain": "string",    "is_valid_domain": true,    "is_free_provider": true,    "verdict": "business"  },  "billing": {    "credits_charged": 0,    "records_charged": 0,    "balance_remaining": 0,    "truncated_due_to_balance": true  }}