# Email API — UnifAPI

> Free email filter: business vs. personal addresses. Classify emails and domains as business, free-provider or invalid against the 4,768-domain list HubSpot forms block, and flag role inboxes. 0 credits.

- Category: Email
- API base URL: https://api.unifapi.com
- Auth: `Authorization: Bearer <UnifAPI API key>` (OAuth recommended for MCP clients)
- MCP server: https://mcp.unifapi.com
- Developer docs: https://docs.unifapi.com/api/email
- OpenAPI spec: https://unifapi.com/openapi.json
- HTML page: https://unifapi.com/apis/email
- Full catalog: https://unifapi.com/apis.md

## Agent workflows

- Gate a signup, demo-request, or lead form on work emails: one check per submission tells the agent whether an address is business, free-provider, or malformed before it reaches the CRM.
- Split a lead list or CRM export into business and personal addresses in batches of 1,000, with role mailboxes such as info@ and sales@ flagged for separate handling.
- Sync the free-provider list into your own code or warehouse with the paged list endpoint, so offline jobs apply the same rule as your forms.

## Endpoints (4)

Every endpoint returns the UnifAPI JSON envelope (`request_id`, `data`, `pagination` on lists, `billing`) and bills max(records × credits per record, minimum) in credits.

### Check if an email uses a free provider

`GET /email/check`

Classify one email address as `business`, `free`, or `invalid`. The domain is matched exactly against 4,768 free email provider domains (the list HubSpot forms block with "Block free email providers", snapshot 2026-10-10); the response also flags role mailboxes (info@, sales@, noreply@) and explains syntax failures. Runs without DNS or SMTP probes, so it is instant and costs 0 credits. Use it to gate signup and lead forms on work emails.

- Price: free (0 credits)
- Required: `email` (query)
- Details: https://unifapi.com/apis/email/check/get
- Docs: https://docs.unifapi.com/api/email/check/get

### Check up to 1,000 emails for free providers

`POST /email/check/batch`

Classify up to 1,000 email addresses in one call, in input order, plus verdict counts. Each address gets the same checks as `GET /email/check`: exact match against 4,768 free email provider domains (the list HubSpot forms block with "Block free email providers", snapshot 2026-10-10), role-mailbox detection, and a syntax check. Use it to split a lead list or CRM export into business and personal addresses. Costs 0 credits.

- Price: free (0 credits)
- Details: https://unifapi.com/apis/email/check/batch/post
- Docs: https://docs.unifapi.com/api/email/check/batch/post

### Check if a domain is a free email provider

`GET /email/domains/{domain}`

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.

- Price: free (0 credits)
- Required: `domain` (path)
- Details: https://unifapi.com/apis/email/domains/domain/get
- Docs: https://docs.unifapi.com/api/email/domains/domain/get

### List free email provider domains

`GET /email/free-domains`

Page through the 4,768 free email provider domains (the list HubSpot forms block with "Block free email providers", snapshot 2026-10-10), sorted alphabetically. Filter with `q` or sync the whole list with `limit=1000` to block free providers in your own code. Costs 0 credits.

- Price: free (0 credits)
- Details: https://unifapi.com/apis/email/free-domains/get
- Docs: https://docs.unifapi.com/api/email/free-domains/get

## Guides

- [Block free email domains on B2B forms](https://unifapi.com/blog/block-free-email-domains) — What the free email domain list covers, where it misfires, and how to apply it with the free API.
- [Free email domain checker](https://unifapi.com/tools/free-email-domain-checker) — Paste a list and split business from personal addresses in your browser, free.

## Related APIs

- [Browser API](https://unifapi.com/apis/browser/index.md) — Markdown, HTML, screenshots, links
- [LinkedIn API](https://unifapi.com/apis/linkedin/index.md) — People, companies, posts, jobs, ads, search
- [GitHub API](https://unifapi.com/apis/github/index.md) — Users, repositories, contributions, trending