Tools / Email finder / Tool
Bounces hurt a sending domain. Before a campaign, run each address through contact.verify: it returns invalid when the mail server refuses the mailbox, valid when it accepts it, and unknown when no verifier can tell. Remove the invalid ones and the send never hits them.
Ask your agent
Verify the 200 addresses in this CSV and give me back only the ones safe to send.
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 | catch_all | |
|---|---|---|---|
| p***@***.com | invalid | Microsoft 365 |
A privacy mailbox listed on a developer platform's site came back invalid on Microsoft 365, so a send to it would be expected to bounce.
Step by step
Take the addresses from the CRM or the sheet the campaign will use.
Run contact.verify on every address, as a batch for a long list.
Drop every invalid verdict from the send. Keep unknown on a separate list.
Send to the valid rows and track bounces; recheck the unknown rows before the next wave.
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.
Verify the 200 addresses in this CSV and give me back only the ones safe to send.
Check this list for bounces, then send the intro email only to the valid addresses.
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": "alex.rivera@example.com"}'curl -X POST https://api.routergrowth.com/v1/run \
-H "Authorization: Bearer $ROUTERGROWTH_API_KEY" \
-d '{"capability": "contact.verify", "input": {"email": "alex.rivera@example.com"}}'Worth knowing
Mailboxes close when people leave a company. A list verified months ago can bounce today.
Unknown means no verifier could decide, often a catch-all or a slow server. It is free, and worth a second check.
The check never delivers a message. Sending is a separate call that you choose to make.
FAQ
No check catches all of them. A mailbox can be valid today and closed tomorrow, and catch-all domains cannot be confirmed.
A permanent refusal, such as a mailbox that does not exist. An invalid verdict predicts this kind.
No. Only valid and invalid verdicts are charged.
Yes. Run contact.verify as a batch, one run per address, with a total cost cap.
More on Email finder
Reading this as an agent? This page as markdown: /tools/email-finder/bounce-checker.md
Connect your agent once. The first calls run on the $1 that comes with signup.