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The MailTester.ninja Insider’s Guide

Everything we know about MailTester.ninja in one document: what it costs, its grades, getting a refund, getting help and what else to look at. Read it here, or keep a copy.

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ToolGPANovember 2026

MailTester.ninja

The Insider’s Guide

Real-time email verifier and finder with a REST API

Every plan, grade, refund rule and rival among email verification and deliverability tools, read from MailTester.ninja’s own pages.

Made by Unlimited & Limited · checked Nov 13, 2026 · toolgpa.com

2.2GPA

Contents

  1. 01WelcomeWhat it is, who it suits, its grades and the ten things to know first
  2. 02What it costsEvery plan, the free plan, ways to pay less and how prices have moved
  3. 03What it doesIts main features, where it runs, what it works with and who makes it
  4. 04Where it standsIts grades against its category, and whether to keep it or make your own
  5. 05The alternativesThe tools it is most often weighed against, side by side
  6. 06Quick answersThe questions people ask about it, each answered in a line or two
  7. 07About ToolGPAWho made this guide, what else is on the site, and how to cite it

ToolGPA put this guide together from MailTester.ninja’s own pages, its app-store listings and our grades. Every fact in it is on MailTester.ninja’s page too, where it is kept up to date. Checked Nov 13, 2026.

Part 01 · Overview

Welcome

What it is, who it suits, its grades and the ten things to know first

2.2

GPA, above 23 of the 61 other email verification and deliverability tools we grade

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.

To get you started, here are 9 things to know about MailTester.ninja, taken from its own pages and our grades.

You pay for a daily limit rather than credits, so requests over it are refused until the next day.
From our report card of MailTester.ninja
  1. 1

    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.

  2. 2

    Paid plans start at $30.29 a month

    As its pricing page puts it: $6.99 per week for up to 100,000 checks a day; $23.99 per month for the same limit.

  3. 3

    There is a 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.

  4. 4

    It runs on Web

    Web.

  5. 5

    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.

  6. 6

    Verdict codes

    Results are ok, ko (invalid) or mb (unverifiable), with messages such as Catch-All, Disposable, Greylisted, Timeout and No MX.

  7. 7

    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.

  8. 8

    A 2.2 GPA, above 23 of 61

    That is against the other email verification and deliverability tools we grade, on value, the free plan, features, ease of use and platforms.

  9. 9

    Keep it

    Nothing MailTester.ninja does is plain enough to make in a weekend. The 2 things listed below take a company.

MailTester.ninja at a glance

Pricing
Free plan, from $6.99 per week for up to 100,000 checks a day; $23.99 per month for the same limit
Free plan
Yes
Free trial
None stated
Runs on
Web
Made by
Unlimited & Limited
Category
Email Verification & Deliverability
Our grade
2.2 GPA, fair

The report card

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.

ToolGPA report cardMailTester.ninjaGraded Nov 13, 2026
SubjectGradeComment
Value for moneyCPro is $23.99 a month, and the weekly Starter is $6.99, about $30 a month. The category's middle is $23.
Free plan and trialCOne-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.
FeaturesCLive mailbox check, verdict codes, finder and tools. An accepted address on a catch-all domain cannot be confirmed to exist.
Ease of useCNo rating on record. Paste an address or call the API; the daily-limit model needs some thought.
Platforms and integrationsBWeb only, but with a REST API, SDKs, an MCP server and a list of integrations.
Grade point averageFair, out of 4.02.2

An A is worth 4 points, a B 3, a C 2, a D 1 and an F nothing. The GPA is the average of the five.

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 it 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

Good to know

Good for

  • Cold-outreach teams verifying large lists at a flat price
  • Developers adding a verification call to automations
  • Users who want to check single addresses without signing up

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.

Part 02 · Pricing

What it costs

Every plan, the free plan, ways to pay less and how prices have moved

$30.29

A month to start. There is a free plan too

MailTester.ninja has a free plan. Paid plans start at $6.99 per week for up to 100,000 checks a day; $23.99 per month for the same limit.

One-off checks on the site are free with no signup.
From our grade for free plan and trial

  • Starter

    $6.99

    per week, billed weekly

    Up to 100,000 verifications and 100,000 API calls a day. Cancel any time.

  • Pro

    $23.99

    per month, billed monthly

    Up to 100,000 verifications and 100,000 API calls a day.

  • Ultimate

    $39.99

    per 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.

The 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.

Read from mailtester.ninja on Nov 13, 2026.

Part 03 · Features

What it does

Its main features, where it runs, what it works with and who makes it

1

Place it runs: Web

Real-time email verifier and finder with a REST API. Here is what it does, as its own site describes it, and what it covers: public API, email verification.

Live mailbox check, verdict codes, finder and tools.
From our grade for 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.

Where it runs

  • Web

What it works with

  • n8n
  • Zapier
  • Make
  • Clay
  • Mailchimp
  • Brevo
  • GetResponse
  • Apify

MailTester.ninja is made by Unlimited & Limited.

Part 04 · Standing

Where it stands

Its grades against its category, and whether to keep it or make your own

23/61

Other email verification and deliverability tools it is graded above

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
  • CFree plan and trialAbove 9 of 61
  • CFeaturesAbove 0 of 61
  • CEase of useAbove 2 of 61
  • BPlatforms and integrationsAbove 28 of 61

Price against what you get

Each dot is one of 45 email verification and deliverability tools. Further left costs less; higher up scores better on features, ease of use and platforms. MailTester.ninja is the marked dot.

D1.0C2.0B3.0A4.0Free$1$2$5$10$20$50$100$200$500$1kMore for lessCosts more, scores moreCosts less, scores lessCosts more, scores lessMailTester.ninjaURIportsReacherReoon Email VerifierWarmup InboxGlockApps

What paid plans start at, a month (each step along is roughly double) →

Keep it, or make your own?

Whether this is something you could build for yourself with an AI app builder, and what you would give up.

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.

Part 05 · Alternatives

The alternatives

The tools it is most often weighed against, side by side

Bouncer, ZeroBounce, Emailable, MillionVerifier and Reoon Email Verifier

The 5 tools MailTester.ninja is most often weighed against, with where each one differs from it.

Part 06 · Questions

Quick answers

The questions people ask about it, each answered in a line or two

13

Questions, each answered in a line or two

The short version of everything above, for when you only need the answer. Each one is told in full in its part of the guide.

Is MailTester.ninja free?

MailTester.ninja has a free plan. One-off checks on the website are free with no signup.

How much does MailTester.ninja cost?

MailTester.ninja lists 3 plans. Starter: $6.99 per week, billed weekly.

What platforms does MailTester.ninja work on?

MailTester.ninja is available on Web.

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.

What does MailTester.ninja integrate with?

MailTester.ninja's listing names n8n, Zapier, Make, Clay, Mailchimp, Brevo, GetResponse and Apify.

Who makes MailTester.ninja?

MailTester.ninja is made by Unlimited & Limited.

What are the alternatives to MailTester.ninja?

The closest alternatives to MailTester.ninja in our directory are Bouncer, ZeroBounce, Emailable, MillionVerifier and Reoon Email Verifier.

How does MailTester.ninja compare with other 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.

Is MailTester.ninja good value for money?

ToolGPA grades MailTester.ninja C for value for money. 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.

Could I make my own version of MailTester.ninja?

Nothing MailTester.ninja does is plain enough to make in a weekend. The 2 things listed below take a company.

Where this guide comes from

The prices, plans, platforms and features were read from MailTester.ninja’s own pages on Nov 13, 2026, and the grades were given on Nov 13, 2026. 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.

Every tool we list gets five grades, A to F, each with its reason, and a GPA that averages them. How each is decided is at toolgpa.com/grades. This guide is ToolGPA’s own work; it is not made, paid for or approved by Unlimited & Limited. Prices change, so check mailtester.ninja before you buy.

Part 07 · About

About ToolGPA

Who made this guide, what else is on the site, and how to cite it

7,721

Tools graded, in 95 categories

ToolGPA grades software the way a school report grades a pupil: five subjects, a letter for each with the reason written beside it, and a GPA that averages them. Prices, plans and platforms are read from each maker’s own pages and dated, so you always know how fresh a figure is.

Every grade, review and ranking on ToolGPA is our own judgement. No company can pay for a grade or change one. Every tool on the site has a guide like this one, free to download and pass on. It all lives at toolgpa.com.

  • 7,721

    tools graded

  • 95

    categories

  • 739

    price changes on record

  • 579

    apps priced in 12 countries

What else is on toolgpa.com

Scan for the live page

Prices and grades as they are today

Quoting this guide?

Please name ToolGPA and link to the live page, so readers can check the figures for themselves:

ToolGPA, "MailTester.ninja: The Insider's Guide", checked Nov 13, 2026. https://toolgpa.com/tools/mailtester-ninja

Know someone choosing between email verification and deliverability tools?

Send them this guide: toolgpa.com/tools/mailtester-ninja/guide

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See our other guides

The best-graded email verification and deliverability tools after MailTester.ninja, each with an Insider's Guide of its own.

ToolGPA

Choosing software? Every tool graded, every price dated.

Compare tools at toolgpa.com ›

Everything in this guide is ToolGPA’s own summary of what MailTester.ninja’s pages, its app-store listings and public reviews said on the dates shown. Grades are our judgement under the rules at toolgpa.com/grades. Every grade, review and ranking on ToolGPA is our own judgement. No company can pay for a grade or change one. MailTester.ninja is a trademark of its owner, and this guide is not made, paid for or approved by Unlimited & Limited. Prices and plans change: check mailtester.ninja before you buy.