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Verify email addresses inside any Zap with the built-in Webhooks by Zapier action: no app to install and no code. MailTester Ninja checks each address against the recipient’s mail server and returns a verdict that your next steps can filter on, so only deliverable contacts reach your CRM, your list or your outreach tool.
What you need
- A Zapier plan that includes Webhooks by Zapier (paid plans).
- A key: a free API token to try it (50 checks a day, one request every 30 seconds) or a paid key for full speed. Use a token rather than
key=free: the keyless tier is counted per IP, and Zapier shares its IP addresses between users.
Set it up in two minutes
- Add an action step and choose Webhooks by Zapier, event GET.
- Set URL to
https://happy.mailtester.ninja/ninja. - Under Query String Params, add
emailmapped to the email field of a previous step, andkeywith your token or key. - Test the step. Zapier reads the JSON answer, and the next steps can use
codeandmessage.
Act on the verdict
Add a Filter by Zapier step: only continue if code (Text) exactly matches ok. To treat each verdict differently, use Paths by Zapier with one path per code.
| code | Meaning | What to do |
|---|---|---|
ok | Valid and deliverable | Continue the Zap. |
ko | Invalid, will bounce | Stop, or tag the contact as invalid. |
mb | Uncertain (catch-all domain, server could not be probed) | Send to a review path, or decide by risk. |
-- | No verdict (key problem, or free limit reached with HTTP 429) | Retry later. Never drop the contact on this answer. |
Verify a whole list
Zapier runs once per record, which fits the rate limit naturally. For a large backfill, throttle the trigger or add a Delay by Zapier step: about 1 second between calls on Pro (11 requests per 10 seconds), 0.45 seconds on Ultimate (23 per 10 seconds), and 30 seconds with a free token.
Keep your key secret
The key sits in the step settings, so anyone who can edit the Zap can see it. Remove it before you share a Zap or turn it into a template.
Questions
Is there an official MailTester Ninja app on Zapier?
Not yet. Webhooks by Zapier does the same job today, and this page will announce the app when it is published.
Is anything stored?
No. Each address is checked in real time and we keep no copy of the addresses you verify.
Try it now
Get a free API token, or see the plans for up to 200,000 checks a day. Full reference: API documentation and OpenAPI specification. Back to all integrations.