A list of SMTP and IMAP servers of popular ISPs

General - Knowledge base

Thank you for visiting the support centre for Spotzee. We hope this support centre will assist you in starting jobs and hopefully answer some of the questions you may have about our service. Our Spotzee email verifier is a complex email address validation software and therefore you would require a decent amount of knowledge to make full use of the complex systems we have in place.

From within the support centre, you can…

- Read articles on our validation process
- Request help regarding just about anything
- Read about what’s happening with us through our blog
- Download and use plugins and 3rd party addons
- Talk with other users
- Talk with our developers directly
- Request features that you would like
- And much much more…

Be sure to check out all this support centre has to offer. We hope that you will find your list cleaning experience enjoyable. We look forward to serving your needs. Get in touch with us if you are experiencing any difficulty. We appreciate your business.

We have been in this communications industry for a very long time (10 years to be precise and counting). We know and understand the importance of email and how it affects businesses. We have cleaned millions of emails and each job improves our system for the better. Here are some other reasons on why we are the best…

- Accurate email address validation
- Validate email addresses in bulk or via API
- Innovative 12 stage cleaning process
- Easy download and upload facility
- Typo correction and Syntax fix ups
- Top-notch security and reliability
- Friendly staff and best support

We allow you to upload any file with custom fields on each column. Our system automatically verifies just the email address column and leaves the other columns intact. Each row data is carried along with the data cleaning process so you will never have to worry about that. Simply upload the mailing list and if there are a lot of custom fields, our system will automatically prompt you on which fields you would like to keep and automatically get rid of the others. This rarely happens. We almost always support a lot of column data to be kept intact while validating. If you have a specific request to keep a lot more fields that our system is allowing, just get in touch with us and we will organize it for you.

Sometimes our customers have data in a single TXT file. Here are some things you must make sure you do before uploading it to us. Make sure each email address is on a seperate line. It should look similar to this:

[email protected]
[email protected]
[email protected]
[email protected]
and so on…

The disadvantage with uploading TXT file is the fact that you can’t have any data besides the email addresses. For example, you cannot have first name or last name alongside each email. This is why we recommend using comma seperated value (CSV) file, which allows you to have data across each row belonging to a particular email address on that row. Another issue with TXT file is the fact that you can’t import anything else besides just the email address. This is another reason why we recommend using a CSV file.

A CSV file is abbreviation for comma-separated values. In simple terms, It is a digital data storage method which separates groups of data with a comma. Every line in a CSV file corresponds to a row in the table. Within a line, commas separate fields, each field belonging to one table column. This simple yet unique structure is what makes this file format very popular and also compatible on almost every operating system. This is why we prefer it too over any other file formats on the market. If you have Microsoft Excel or Openoffice installed, you are able to view it in similar fashion to the image below. Open the same file using Notepad, TextEdit or similar application and you will see its raw data stored using commas as the name suggests.

bob,503, bobby

Many of you might wonder what happens to any unused prepaid credit. After you top up, the validity of these credits lasts forever. There is no expiry date. You can top up and use it whenever you choose.

Time to time, we have customers who get back to us saying, your software didn’t clean all the bounced email addresses or I have a lot of bounces even after using your validation software. Here’s why you may still have some bounces and why we don’t guarantee 100% bounce removal. We can assure you that no one in our industry is even close to those figures. Now there are a number of reasons why our system would mark emails as valid but it ends up as bounced address.

1) THE MAILBOX IS FULL (this is the most common) - So although the mailbox is available and ready to receive messages, it just can’t accept any further messages because it hasn’t been used for a long time.

2) THE CATCH-ALL ADDRESSES - This is when the mail server accepts any message delivered to its mail servers (Eg. *@domain.com). These addresses are particularly harder to verify because nearly 90% of the time, they are valid but that rest of 20% can sometimes cause bounces. You can go to our competitors and they do no better job at identifying these. We are still developing technology that could eliminate this.

3) THE TIME OF VALIDATION - When we validate, the mailbox might have been active and when you actually sent it might have been inactive or invalid. This is rare but does happen time to time.

4) IT COULD BE THE IP OR PROVIDER - you are using a provider to send your email campaigns. This happens to be the most obvious one. Some email providers don’t have such a great reputation with services like Gmail, Yahoo, or even private email providers. Therefore, any email campaigns you send with them could be reject on the basis of their IP being listed in blacklists. This is nothing to do with how valid an email is, its just to do with the IP address or provider you are using to send their email campaigns.

5) IT COULD YOU EMAIL CONTENT - Even if we provide you with 100% valid email addresses, if your email content isn’t up to scratch, it will bounce back and your message is likely to be rejected by the providers. This is not something we can help you with. We suggest checking your email campaign against solutions like SpamAssassin and adjusting to make it high quality email campaign ready to be delivered without issues.

6) IT COULD BE YOUR SENDING PRACTICES - Most providers have set of guidelines that must be followed if you want them to deliver mail to your customers. They are often referred to as bulk sender guidelines. One of the most popular guides is from Gmail. They check your email against things like SPF, DKIM, DMARC, rDNS and others to determine whether they should deliver or reject your email outright. This is again not to do with how valid an email address is but more on if you are following the guidelines for becoming a good sender.

EMAIL DELIVERABILITY IS COMPLEX and involves a lot more things than what we mentioned here. We suggest you get guidance from your provider and from online resources. This will help you achieve better deliverability. Also keep in mind that email validation is to help you eliminate majority of the bounces.

SPOTZEE EMAIL VALIDATION IS NOT A TOOL TO REMOVE ALL THE EMAIL ADDRESSES THAT ARE LIKELY TO BOUNCE. If some of our competitors are promising you that they will get rid of 100% bounces, they are most likely issuing a false statement or sending blank emails (unethical behavior) behind your back. Even by sending blank emails, they still cannot guarantee you with 100% bounce removal.

Time to time, customers come to us asking us why they still have some complainers or spam-trap email addresses in their verified email list. Here are some reasons to consider…

1) IT MAY NOT BE TRUE - You would need a solid evidence that what you believe is a spam-trap email address is actually a spam-trap email address. Most of these emails are kept a secret to fulfill their objective of catching the bad guys. That’s the aim. If everyone knew which email addresses were honey pots, then there is no point in keeping them active. So we ask our customers, what makes them think that its a spam-trap email address.

2) NOT ALL COMPLAINERS ARE REGISTERED - Every person who doesn’t want to receive any marketing email campaigns is registered. Each complainer registers through different services and sometimes we do not have them in our database. Although we make a great effort in adding new complainers databases to our existing one, we might not have them all. We are happy to admit that.

 3) WE DON’T KNOW IT ALL - We currently have millions of spam trap and millions of complainer email addresses in our databases and regularly we update these databases from live feeds but that wouldn’t cover ALL the bad email addresses in the world. They do end up deactivating or activating new ones. We continually work on having more live feeds implemented as the years go by. This allows good senders like yourself to stay off these traps. Besides this, we use complex AI algorithms to do the predicting so we are able to cover a lot of emails with certainty that it belongs to a spam trap. See our blog on published results of our predictors.

Please take note that we only reduce your chances of getting into blacklists. We never say anywhere that we will remove 100% of all spam trap or complainer email addresses. Because none of the companies out there can. These emails are supposed to be secret addresses from ESPs. If everybody found out about them, there is no point in having those email addresses. If any company is stating that they can get rid of all the complainers or spam trap email addresses, we are 100% sure they are issuing a false statement. We suggest that you stay far from such scams.

Email validation involves a number of processes. To complete each of them correctly and accurately would take time. There are a lot of things involved which makes it really hard to predict the exact or close time of completion.

As a very general guideline, our system process a list of 10,000 email addresses in less than 10 minutes but please don’t quote us on this as you will see why this could differ by reading the information below.

Some of the factors that affect timing include…

1) DOMAIN FREQUENCY - If you have a lot of emails from the same ESP or provider (Eg. Lots of Gmail Addresses), its more time consuming to verify. This is because Gmail and many other ESPs have limits on how many connections it would accept from same IP address or network. If we exceed that, it would likely cause them to block us. This would only give us inaccurate data about those email addresses we are trying to validate.

2) SPAM-TRAP ADDRESSES OR COMPLAINERS - At date of writing this, we have local database of more than 365+ million spam-trap records and in excess of 120+ million complainer addresses. So for example, if you upload 10,000 email addresses…just to verify against our own local databases, it would have to scan each single record against nearly 40 million or more email addresses. Pretty mind boggling isn’t it? Therefore, this could be a little time-consuming process if we want quality results.

3) NETWORK SPEED - This is highly unpredictable in any given environment. Sometimes, it’s blazing fast speeds and sometimes its a little slower. In addition to this, add numerous amount of validation jobs that come through from 1000s of customers worldwide. So to manage it all, our engineers continually optimise our servers and network but there is very little we can do to speed it up even further. This also affects the speed of your verified results.

4) LARGE LISTS - If you have uploaded a large list (Anything above 10,000 emails), we would have to make sure all is well before we start your validation job. These are often referred to as pre-validation checks. They include things like deduplication which involves verifying every single email address on your mailing list against every single other record on your list. Quite a tiresome process if you think about it. Despite the complexity, our system handles it quite well. It does most jobs within seconds and prepares the files for validation.

5) MISCELLANEOUS - With technology, there are quadrillion things that are involved. There are quite a lot of other reasons why your validation job might be taking time. To list everything involved down here would not only be a waste of time but also pointless to users because most of it cannot be put into simple understandable language.

Just rest assured that our team will be doing everything in their power to get your validation job processed as soon as we can.

So you have signed up for an email validation account and now you are excited to start using it. Here are some guidelines to help you make the most of our service. We highly recommend that you follow these guidelines to achieve great validation results.

This is possibly the most important guideline to follow. Currently we only accept CSV or TXT files. You can see the benefits of using CSV above.

To prepare a TXT file is more simpler because TXT files only contain email data set. Make sure your TXT file is free from formatting issues (irregular special characters etc). It shouldn’t contain commas or any such characters. If you see your TXT file containing commas or semicolons, its most like a CSV file with wrong file extension.

Quite often we get CSV files which look like this. Obviously this is not a CSV (comma separated values). Simple replace all the ‘;’ semicolons with commas. You can do this in windows by hitting ‘Ctrl + F’ or on Mac ‘Apple key + F’. You can also use tools online such as Text Mechanic. One the easiest ways to fix this is mass replacing the semicolons with commas like this.

Sometimes we get customers uploading data which has more than one column of email addresses. Usually they are referred to as primary email and secondary email. While we are more than happy to clean both primary and secondary email, our system only accepts emails in one single column. We suggest you create a new record for all secondary email. That way our system can clean both records and validate emails accurately.

We recommend that you get rid of records with no email addresses because at the end of the day our system is verifying your customer’s email address not their name or address. If there is no email address associated with the record, it will most likely return back to you as invalid/unknown. On top of this, you end up paying for a record which we all know will return as invalid since there are no email addresses to verify.

Secondly, avoid columns which are blank. We have seen headers that have no data in them. Its just unnecessary to keep it there and its best if you remove blank column data. Our system can still verify with blank column data but we recommend to remove it for a much easier to read validation results.

Assuming that you are logged in your account, click on ‘My account’ by hovering over the display pic or your name displayed on the top right corner of the control panel. From the choice of tabs, pick ‘API & Integration’ by clicking on it. You should now see your API key displayed. If you would like to reset this API key, you can login and click ‘reset’ icon. You can start using this API key to build powerful email validation apps or integrate into your existing platform or application. See our email validation API calls documentation for more information.

EV Score is a good indicator of the quality of the email address in question. Our system can correctly validate if the email address is valid or not but even if we determined it to be valid, it doesn’t mean to say that there will be a good response from that email address. This is why EV score is important. It lets you determine which email addresses you can send with confidence and which email addresses you need to take caution with. One of the simplest way we could explain how SendEV works is by distinctions such as this ‘[email protected]’ would be considered a higher quality email address than ‘[email protected]’.

Spotzee email validation uses a number of algorithms, derived from scanning through millions of email transactions to determine the overall quality of an email address. Some of the things we look for is as follows:

- How similar or dissimilar an email address appears to known, high-quality email addresses that our system is evaluating or has evaluated in the past. It learns by evaluating patterns of what makes up a good email address and thereby provides insight into the overall quality of a given address.
- The type of domain it is under such as a corporate email address (@bigcompany.com) vs a free email service provider (@gmail.com)
- The association an email address has with a person. A role-based email address is less likely to have a person attending to emails than an email address associated to specific people or contacts ([email protected])

A higher EV value score indicates a good quality email address while a lower score might potentially have higher spam or bounce rate issues. We recommend sending to lower EV with caution. The value itself is anywhere between 0 and 1.

Here are some recommendations for Transactional and Marketing Emails.

1.00-0.55 - Good
0.54-0.020 - Ok
0.19-0.00 - Poor

1.00-0.70 - Good
0.69-0.40 - Ok
0.39-0.00 - Poor