MailTester.ninja review (2026): is the free plan enough?
Real-time email verifier and finder with a REST API
Black Friday: is there a MailTester.ninja sale?
MailTester.ninja report card
Fair · out of 4.0 · graded Nov 13, 2026
Best for checking addresses through a daily-limit API
MailTester.ninja verifies addresses live and has an email finder, a REST API, SDKs and an MCP server. You pay for a daily limit rather than credits, so requests over it are refused until the next day.
Who MailTester.ninja is for
- Fits if you want a steady stream of live checks from an API
- Works for people who check a few addresses by hand on the free site
Who MailTester.ninja is not for
- Tight if you work in bursts, as requests over the daily limit are refused until the next day
- Skip it if you want credits that carry over, since plans are priced by daily limit
- Watch out: Starter is billed weekly, and the monthly plans are Pro and Ultimate
- Watch out: free API calls are 10 or 50 a day, one every 30 seconds
- Watch out: a catch-all domain's accepted address is not proof the mailbox exists
Why MailTester.ninja gets a 2.2
Five grades, each with its reason. The GPA is their average: an A is 4 points, an F is none.
- CValue for moneyPro is $23.99 a month, and the weekly Starter is $6.99, about $30 a month. The category's middle is $23.
- CFree plan and trialOne-off checks on the site are free with no signup. The free API allows 10 checks a day, or 50 with a 7-day token, one request every 30 seconds.
- CFeaturesLive mailbox check, verdict codes, finder and tools. An accepted address on a catch-all domain cannot be confirmed to exist.
- CEase of useNo rating on record. Paste an address or call the API; the daily-limit model needs some thought.
- BPlatforms and integrationsWeb only, but with a REST API, SDKs, an MCP server and a list of integrations.
What these grades rest on. Graded from this listing, whose facts were read from MailTester.ninja's own pages on 13 November 2026. Not based on using the product, and shorter than our full reviews. How we review and grade.
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<a href="https://toolgpa.com/tools/mailtester-ninja#review"><img src="https://toolgpa.com/badge/mailtester-ninja.svg" alt="MailTester.ninja: 2.2 GPA on ToolGPA" width="196" height="56"></a>Where MailTester.ninja stands among email verification and deliverability tools
MailTester.ninja's GPA of 2.2 is higher than 23 of the 61 other email verification and deliverability tools we grade, and level with 13.
It stands best on platforms and integrations (B, above 28 of 61) and worst on features (C, above 0).
Its paid plans start at $30.29 a month, against a middle price of $21.50 for the category: 29 of the 43 others that charge start lower.
On features, ease of use and platforms it scores 2.3 out of 4. 7 tools score higher and cost less.
Each grade against the category
Every bar is all 62 email verification and deliverability tools we grade, cut by the letter each got. MailTester.ninja’s own letter is outlined.
- CValue for moneyAbove 9 of 61, level with 35
- CFree plan and trialAbove 9 of 61, level with 43
- CFeaturesAbove 0 of 61, level with 45
- CEase of useAbove 2 of 61, level with 50
- BPlatforms and integrationsAbove 28 of 61, level with 33
Price against what you get
Each dot is one of 45 email verification and deliverability tools. Further left costs less, and higher up scores better on features, ease of use and platforms. Point at a dot to see which tool it is.
Features, ease of use and platforms, averaged
What paid plans start at, a month (each step along is roughly double) →
- The best score at each price
- Has a free plan
- No free plan
Keep MailTester.ninja, or make your own?
Keep it
Nothing MailTester.ninja does is plain enough to make in a weekend. The 2 things listed below take a company.
It costs $363.48 a year.
What you could not
- Checking that an address exists without writing to it.
- It plugs into other products, n8n, Zapier and Make among them, and has an API.
What this rests on. MailTester.ninja’s listing: what it does, where it runs, what it plugs into and what it costs. It is a judgement about the kind of software this is. We have not built a replacement for it, and making your own means looking after it too. How we decide, and every tool’s verdict.
What is MailTester.ninja?
MailTester.ninja checks whether an email address exists by asking the recipient's mail server, without sending a message, and says it stores none of the addresses submitted. It also finds work email addresses from a name and company domain. One-off checks are free, and paid keys raise the daily limit and unlock the API.
Worth knowing
- Free API calls are limited to one request every 30 seconds, and 10 or 50 checks a day.
- Plans are priced by a daily limit, not a credit balance: requests above it are refused until the next day.
- Starter is billed weekly; the monthly plans are Pro and Ultimate.
- An accepted address on a catch-all domain cannot be confirmed to exist.
Key features
- Live mailbox check
- Each address is tested against the recipient's mail server (syntax, DNS, MX and an SMTP handshake). No message is sent, and the page says no copy of the address is kept.
- Verdict codes
- Results are ok, ko (invalid) or mb (unverifiable), with messages such as Catch-All, Disposable, Greylisted, Timeout and No MX.
- Email finder
- Tries common address formats such as first.last and flast for a name and company domain, and returns the first the server accepts. The Finder API needs a paid key.
- REST API, SDKs and MCP server
- Two endpoints, an OpenAPI 3.1 spec, JavaScript and Python SDKs and an MCP server for AI agents.
- Deliverability tools
- The site also offers a domain audit report, a sender score test for a sent email and a blocklist checker.
MailTester.ninja pricing
As of Nov 13, 2026, MailTester.ninja has a free plan, and paid plans start at $6.99 per week for up to 100,000 checks a day; $23.99 per month for the same limit.
- Starts at
- $6.99 per week for up to 100,000 checks a day; $23.99 per month for the same limit
- Free plan
- One-off checks on the website are free with no signup. The API allows 10 checks a day with key=free, or 50 a day with a free token valid for 7 days.
- Free trial
- None listed
| Plan | Price | What you get |
|---|---|---|
| Starter | $6.99per week, billed weekly | Up to 100,000 verifications and 100,000 API calls a day. Cancel any time. |
| Pro | $23.99per month, billed monthly | Up to 100,000 verifications and 100,000 API calls a day. |
| Ultimate | $39.99per month, billed monthly | Up to 200,000 verifications and 200,000 API calls a day. A quantity above 1 multiplies the limit, so 5 gives 1 million a day. |
Read from mailtester.ninja on Nov 13, 2026. Prices change, so confirm with MailTester.ninja before you buy.
Works with
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Common questions
Does MailTester.ninja have an Android app?
No Android app was listed when its pages were read on Nov 13, 2026. MailTester.ninja is listed for Web.
Does MailTester.ninja have an iPhone app?
No iPhone app was listed when its pages were read on Nov 13, 2026. MailTester.ninja is listed for Web.
Is MailTester.ninja open source?
MailTester.ninja is not described as open source on its own site, as read on Nov 13, 2026.
Does MailTester.ninja have an API?
Yes. MailTester.ninja offers a public API, according to its own site.
Sources for this page
The prices, plans, platforms and features above were read from these pages on Nov 13, 2026.