# Check whether a mailbox accepts mail before you trust it

Paste an email address. contact.verify asks the mail server whether that mailbox exists and returns valid, invalid or unknown, with the catch-all flag, the mail provider (Google Workspace, Microsoft 365) and the company behind the domain. When one verifier has no answer, the next one tries in the same call.

HTML page: https://www.routergrowth.com/tools/email-finder/checker
Part of: [Email finder tools](https://www.routergrowth.com/tools/email-finder.md)

## The call

[`contact.verify`](https://www.routergrowth.com/catalog/contact.verify): Verify deliverability of a professional email: valid, invalid, or unknown, with catch-all and mail-server details.

Price on this network: $0.002 per verdict. The exact quote is shown before every run.

## What a real run returned

Run on 2026-10-26: 1 records in 15.0 s for $0.0125. Personal fields are masked. A press mailbox printed on a company site: two verifiers gave no verdict, the third returned invalid on Google Workspace.

| email | status | mx_provider |
|---|---|---|
| p***@***.com | invalid | Google Workspace |

## How to do it

1. **Paste the address.** One address per call. For a list, run the calls as a batch.
2. **Call contact.verify.** The verifiers are tried in turn until one gives a verdict.
3. **Read the status.** valid means the mailbox accepts mail, invalid means the server refused it, unknown means no verifier could decide.
4. **Decide.** Send to valid, drop invalid, and recheck unknown later or ask for another address.

## Ask it like this

- Check these five addresses and tell me which ones are safe to email. (`contact.verify`)
- Find the work email of Alex Rivera at example.com, then check it before I write. (`contact.find`, `contact.verify`)

## Connect

MCP server: `https://api.routergrowth.com/mcp`

```bash
claude mcp add --transport http routergrowth https://api.routergrowth.com/mcp
```

```bash
npm install -g routergrowth && routergrowth setup
routergrowth run -c contact.verify -i '{"email": "press@example.com"}'
```

```bash
curl -X POST https://api.routergrowth.com/v1/run \
  -H "Authorization: Bearer $ROUTERGROWTH_API_KEY" \
  -d '{"capability": "contact.verify", "input": {"email": "press@example.com"}}'
```

## Worth knowing

- **Role mailboxes behave differently.** A press or support address printed on a site can still come back invalid, because group mailboxes often do not answer like a personal inbox. Treat invalid as do not send, and confirm a key address another way.
- **Unknown is free.** Only a valid or invalid verdict is charged. When a verifier cannot decide, the next one tries at no cost.
- **No email is sent.** The check talks to the mail server; nothing lands in the inbox.

## Questions

### What does invalid mean?

The mail server said the mailbox does not exist or will not take mail. A send to it would most likely bounce.

### What is a catch-all domain?

A domain whose server accepts every address, so a single mailbox cannot be confirmed. The catch_all field flags it when the verifier reports it.

### Why did several verifiers run?

The first two had no verdict for this address. The router moved on until one answered, all in one call.

### Can I check role addresses like press or support?

Yes. In this run two verifiers had no verdict for a role address and the third one answered.

## Related

- [Spot an address someone made up on a real company domain](https://www.routergrowth.com/tools/email-finder/fake-checker.md)
- [Find the addresses that would bounce, before the campaign goes out](https://www.routergrowth.com/tools/email-finder/bounce-checker.md)
- [Find where to reach a brand from its YouTube channel](https://www.routergrowth.com/tools/email-finder/youtube.md)
- [Read a TikTok brand account's bio, links and contact email](https://www.routergrowth.com/tools/email-finder/tiktok.md)
- [Find the contact details a brand lists on its social profiles](https://www.routergrowth.com/tools/email-finder/social-media.md)
- [Check whether an email address will accept mail before you send](https://www.routergrowth.com/tools/email-finder/verification-tools.md)
- [Turn the LinkedIn profile you are reading into a verified work email](https://www.routergrowth.com/tools/email-finder/linkedin.md)
- [Get the email and links an Instagram brand account shows](https://www.routergrowth.com/tools/email-finder/instagram.md)
- [Get work emails for the people you want at one company](https://www.routergrowth.com/tools/email-finder/company.md)
- [Find someone's work email from their name and where they work](https://www.routergrowth.com/tools/email-finder/by-name.md)
- [Verify one email address in the middle of a conversation](https://www.routergrowth.com/tools/email-finder/address-verification.md)
- [Verify a whole list of emails without uploading it anywhere](https://www.routergrowth.com/tools/email-finder/bulk-verification-software.md)