Tools / Email finder / Tool
A form can look clean while the address is invented: a real company domain with a mailbox that does not exist. contact.verify asks the mail server and returns invalid for those, valid for a real mailbox and unknown when no one can tell. Use the verdict to block, warn or tag the signup.
Ask your agent
Check yesterday's 300 trial signups and tag the ones with a mailbox that does not exist.
Connect RouterGrowth once, then ask in plain words. New workspaces start with $1 of credit. Get a key or read the setup guide.
A real run
One call to contact.verify (email deliverability check), run through RouterGrowth on October 26, 2026. These are the first rows it returned; fields that name a person are masked.
| status | mx_provider | company | |
|---|---|---|---|
| p***@***.com | invalid | Google Workspace | Shopify |
A made up role address on a real commerce company's domain: the domain and mail server exist, the mailbox does not, so the verdict is invalid.
Step by step
Call contact.verify when the address is submitted, or on a nightly batch of new signups.
invalid means the mailbox does not exist, even if the domain is real.
Block invalid, let unknown through with a flag, and accept valid.
The response names the company behind the domain, a quick check on the signup's claimed employer.
Price
List prices on this call, read from the catalog when this page was built. The exact figure is quoted before every run, and a monthly plan lowers it.
In practice
You describe the job; the agent picks the calls, shows the price and runs them.
Check yesterday's 300 trial signups and tag the ones with a mailbox that does not exist.
Flag fake addresses in this lead form export, then enrich the company of each valid one.
Connect
One MCP server for Claude, ChatGPT, Claude Code, Codex and Cursor, or the same call over the CLI and REST with the input above.
claude mcp add --transport http routergrowth https://api.routergrowth.com/mcp
npm install -g routergrowth && routergrowth setup
routergrowth run -c contact.verify -i '{"email": "jordan.lee@example.com"}'curl -X POST https://api.routergrowth.com/v1/run \
-H "Authorization: Bearer $ROUTERGROWTH_API_KEY" \
-d '{"capability": "contact.verify", "input": {"email": "jordan.lee@example.com"}}'Worth knowing
The domain here belongs to a large company with working mail. Only the mailbox was invented, and the check caught it.
The call checks the mailbox. It does not judge the person, the IP or the intent behind a signup.
Some domains accept any address. Those come back unknown or catch-all, and need another signal.
FAQ
It reports whether the mailbox accepts mail. It does not keep a list of disposable providers, so add that rule yourself if you need it.
A check took about 15 seconds here when the first verifiers had no answer. Run it after the form is accepted if speed matters.
No. No email is sent; the check only asks the mail server.
Only a valid or invalid verdict. Unknown results are free.
More on Email finder
Reading this as an agent? This page as markdown: /tools/email-finder/fake-checker.md
Connect your agent once. The first calls run on the $1 that comes with signup.