About BillionVerify

BillionVerify is an email verification service. It tells you whether an email address can receive mail before you send to it. Each check covers syntax, the domain and its MX records, then asks the receiving mail server whether the mailbox exists, and stops before any message is sent. You get one status per address: valid, invalid, catch-all, role, disposable or unknown.

Check one address in the dashboard, clean a whole list, call the email verification API from your own product, or let an AI agent verify addresses through the MCP server.

• 20 free credits every day you log in, up to 600 a month
• 1 credit per address with a definite result; unknown results are free
• Credits never expire, whether you buy them or earn them

Verifies single email addresses

Type an address and get its status, the reason behind it and a 0.0 to 1.0 deliverability score. The email verification check runs syntax, domain, MX and SMTP mailbox steps in one request.

Cleans email lists in bulk

Upload a CSV or Excel (XLSX) file in the dashboard, or send CSV, TXT or XLSX files through the API, and BillionVerify verifies every row. Download the results filtered by status, with your original columns kept. See bulk email verification.

Verifies emails through an API

The REST API verifies one address, a batch of up to 50 addresses, or a whole file as a background job with a webhook when it finishes. SDKs are available for Node.js, TypeScript, Python, Go, PHP and Java. Start with the API reference.

Works with AI agents

A hosted MCP server lets Claude, ChatGPT, Cursor and other MCP clients verify addresses after the user signs in with OAuth. Agent skills add the same check to agent frameworks without integration code.

Finds work email addresses

The email finder turns a name and a company domain into a verified work address, for 10 credits per address found and nothing when no address is found. The bulk email finder does the same for a CSV, and company search lists the verified addresses behind a domain for 5 credits per address returned.

Connects to the tools you use

The WordPress plugin checks addresses in WordPress forms, and the n8n community node adds verification to n8n workflows. The integration guides show how to connect Zapier, Make, HubSpot, Mailchimp, Shopify, WooCommerce and web frameworks through the API.

Offers free email tools

Free email tools cover single-address checks and DNS work: SPF, DKIM and DMARC generators and checkers, MX and DNS lookups, a blacklist checker, a header analyzer and an email deliverability test.

It asks the mail server, not a pattern

A valid-looking address can still bounce. BillionVerify connects to the receiving mail server over SMTP and asks about the exact mailbox, so invalid means the server rejected it, not that the address looked wrong.

You pay for answers, not for attempts

An address costs 1 credit only when the result is definite. unknown results, disposable addresses and badly formatted addresses are free, and checking the same address again within 24 hours is free too. See which results consume credits.

It says unknown instead of guessing

Some mail systems, such as Apple iCloud and personal Outlook and Hotmail addresses, do not give a reliable answer. BillionVerify returns unknown for them rather than a guessed valid, and does not charge for it.

Prices fall with volume, with no expiry

Credit packs start at $20 for 20,000 credits ($0.001 per email) and go down to $0.00014 per email on yearly plans. Buy credits once or subscribe monthly or yearly; credits you hold never expire. See pricing.

Built for people and for agents

The same verification runs in the dashboard, the API, the MCP server and agent skills, so a list you clean by hand and a sign-up form your code checks get the same answer.

Email marketers

Clean a list before a campaign to keep the bounce rate down and protect the sending domain.

Sales and outbound teams

Verify prospect lists from lead databases before cold email, and find work addresses with the email finder.

SaaS and product teams

Check addresses at sign-up through the API to stop typos, disposable inboxes and fake accounts.

Agencies

Clean lists for clients, or resell verification under your own brand with the white label service.

Developers and AI agent builders

Add verification to an app, a workflow or an agent with the API, the SDKs or the MCP server.

1. Create a free account.
2. Verify one address, upload a list, or create an API key in the dashboard.
3. Each address goes through syntax, domain and MX checks, then an SMTP mailbox check.
4. Read the status, reason and score for each address, or download the list filtered by status.
5. Buy a credit pack or choose a monthly or yearly plan when the free credits run out.

• What is kept: the addresses you verify and their results are stored in your account's verification history. Uploaded source files can be downloaded for 1 day; result files stay with your results. See data retention.
• Sign-in: Google, an email sign-in link or a password, with optional two-factor authentication through an authenticator app, an email code or backup codes.
• API keys: stored only as hashes, and you can disable or delete a key in the dashboard at any time.
• In transit: all traffic uses HTTPS (TLS). See security.

• Email verification: check one address with a live SMTP mailbox check.
• Bulk email verification: upload a list and download it cleaned and sorted by status.
• Email verification API: verify addresses from your own product or workflow.
• Email finder: find a verified work address from a name and a company domain.

What is BillionVerify?

BillionVerify is an email verification service. It checks whether an email address can receive mail by asking the receiving mail server about the mailbox, and returns a status for each address. You can use it in the dashboard, through the REST API, or from an AI agent through the MCP server.

What is email verification?

Email verification is checking whether an email address exists and can receive mail before you send to it. A full check covers the address format, the domain, its MX records and an SMTP conversation with the mail server that stops before a message is sent.

Does BillionVerify send an email to the address?

No. The SMTP check stops before any message is sent, so the person behind the address receives nothing.

Why do some addresses come back as unknown?

Some mail servers, including Apple iCloud, personal Outlook and Hotmail, and servers that throttle or greylist, do not give a reliable answer about a mailbox. BillionVerify returns unknown for these instead of guessing, and does not charge for them.

How much does BillionVerify cost?

You get 20 free credits every day you log in, up to 600 a month. Credit packs start at $20 for 20,000 credits, and monthly and yearly plans bring the price down to $0.00014 per email. Each address with a definite result costs 1 credit, and credits never expire.

Can AI agents use BillionVerify?

Yes. Connect an MCP client such as Claude, ChatGPT or Cursor to the hosted MCP server and sign in with OAuth, or add the agent skills to your agent framework. Agents can also call the REST API with an API key.

How do I contact BillionVerify?

Email support@billionverify.com with your account email and what happened, or use the contact page. Answers to common questions about results and billing are in the help center.