On-Demand Email Checker: your application verifies the email address of your users, on demand, by calling our webservice api

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Call the api in the desired format (json, xml, text) with a simple https call...


... and get the answer in less than one second:


Detect if a given email address is invalid

On Demand Email Checker gives you the confirmation, for each email submitted, whether it is a valid email address or not.

Common detected errors

wrongly entered, mispelled domain name, mispelled username, inexisting email account, inexisting domain, disposable address, account over quota...

How it works

For each email submission, our tool connects to the email server, simulates sending a message, and verifies if the mailbox really exists. No actual email is sent.


Don't lose half of your subscribers with double opt-in.
Check your user's email in 1 second, with a simple https call.

Better deliverability

Sending emails to invalid adresses results in hardbounces and low email open rate that get your future emails labelled as spam. Improve your deliverability and increase your email open and click rates!

Save your money

Don't waste your money sending emails to inexisting mailboxes!

Increase your revenue

Detect invalid emails in real time in your application and then act to request a correction. Get valid email addresses that would have been lost.


Here are the main features of On-Demand Email Checker

On demand call

You request a verification by calling the API, whenever you want, as many times as you want

Real-time verification

Deltadromeus checks email addresses, in real time, every time you make a request, in 1 second on average!

Easy to use

Our OnDemand Mail Checker solution is easy to use: it is a simple https call, with the address to be verified and your personal API key passed in GET or POST argument. Our support team is available for any help.


Purchase of a volume of email address verifications, to be consumed on demand and valid for 1 year

1,000 verifications - $6.99
for high-volumes, contact us

No subscription. No hidden fees. You buy a quantity of checks that you consume as and when you want. When you run out of them, you can buy more. 100 verifications offered to begin with.

Stop losing revenue.
Start sending emails to real people.

Let's Get Started!

We our clients!

Our solution has been designed to be used as simply and efficiently as possible. Very few technical knowledge is needed to use it. OnDemand Mail Tester is an easy-to-use tool with a limited development need. Our team is available to help you and support is free.

Description of the tool

On-Demand Email Checker is a live mail address checker webservice tool for websites or applications that need, for example, to verify the email address of their new users.

A live email address verification service

If you have a website or a mobile application where many people sign up, you probably know that some of the emails are not valid, for various reasons, including the typo. Do you monetize your users by offering them, directly or indirectly, your services or products by sending emails? you know that each incorrect email address is a shortfall! Ensure the validity of an email through an email checker webservice. Deltadromeus OnDemand Mail Checker is the service you need. You can call, each time someone sign up on your website (or whenever you want), the webservice to make sure its email address really exists. You have the hand, on your website, to accept or reject the email address of your visitors.

The most flexible mail tester webservice

This is the most flexible live email checker, because you call it when you want, and get the result immediately (1 second on average) to process the request in real time directly on your website or web application. On Demand Email Verifier is fully configurable to suit your needs: maximum acceptable response time, acceptance or refusal of an email address in case of doubt (server unavailable or impossibility to determine the existence).

Simple use of an api, minimal development

The use of Deltadromeus Email Checker on demand is very simple. A simple web call over https to the email checker api with the email address to be tested gives you the answer. This requires very little web development and examples of uses are available for the main programming language, such as PHP or Java.

An affordable and flexible price

You buy credits according to the volume of email to check among the lowest on the market. The higher the volume, the more the price per verification is decreasing. Then, every time you use the check email api, a credit is consumed. You recharge when you want, the desired volume. There is no commitment, no hidden fees!

At your service

The Deltadromeus team, as for all its products and services, is at your disposal to help you in the use of its tools. But above all, we are at your disposal to adapt the products to the needs you have and that you entrust to us. You want to accept only existing email addresses without any doubt? or conversely you want to accept any email address tested even if in doubt? All of this is for example possible. And if you have a new need, just ask us to add it to our online mail checker.

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