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Tips & Tricks to Increase Email Deliverability
Tips & Tricks to Increase Email Deliverability
Vincenzo Ruggiero avatar
Written by Vincenzo Ruggiero
Updated over a week ago

86% of the worldwide email traffic is spam. In response to that, spam filters and anti-spam organizations have become harder to fool. This is why you, as a cold emailer, might have a hard time reaching your prospect's inbox 100% of the time.

But it doesn't mean it's impossible or – at the very least – that you can't reach most of them. You just need to know how to overcome the hurdles of spam filters. Here are a few tips to help you.

Don’t buy email lists

Reaching your quota is important, but while it may be tempting to buy prospects lists, don’t do it. Purchased lists won't benefit your business. Those lists are full of unqualified addresses that won't get you any results.

Purchased lists generally contain poorly verified email addresses, resulting in a higher bounce rate and weaker deliverability. It’s always worth taking the extra time to identify quality leads.

Avoid SPAM trigger words

Email Service Providers (ESPs) use a variety of methods to fight SPAM. One very simple method is to detect words that are used a lot in SPAM emails.

One of the first things you should do to increase your email deliverability is to avoid these words in your emails.

Use a SPAM checker tool

Before sending your e-mail, take a minute to get it through a spam checker like It’s free, and it will test your emails for the main liabilities that could impair their efficiency. It’s an easy way to avoid the spam folder. Use it.

Check your spelling

Besides being very unprofessional, poor spelling is an instant sign for Email Service Providers (ESPs) that there might be a scam going on.

Therefore, if you don’t want to end up being flagged as SPAM, do a thorough spell-check before sending your emails, especially if you’re sending a drip campaign to hundreds of prospects.

Keep your emails short

Long emails do not work well for cold emailing. Try to avoid sending more than 3 paragraphs in an email.

If you absolutely must send a long email, break it into multiple paragraphs in order to make it readable and clear for your recipient.


Clickable images and redirections to a landing page have become standard practice and should stick around for a while. However, you should only include links to reputable domains, or they might be flagged as fraudulent.

Also, avoid URL shorteners. They are usually used by spammers, and your emails could be flagged by SPAM filters.


Overloop allows attaching files to emails in a safe way that does not impact the deliverability of your emails.


While it is understandable that you really want your emails to be opened, don't be overenthusiastic, and don't make claims that don't match the content of your emails.

Words and expressions like “this isn’t spam”, “make money”, “satisfaction guaranteed” or “no obligation” are obvious red flags for SPAM filters.

From name

Mailbox providers don’t just evaluate the IP and domain, they also check the From field.

This is why you should use clear and trustworthy names like only! or are a no-go and will put your domain at risk.

Use a reliable Email Service Provider (ESP)

What is an ESP and why does it matter?

ESP stands for Email Service Provider. It refers to a company that offers you all kinds of services related to sending commercial emails. It is counter advised to use a regular email address to send emails in large quantities as you may:

  1. Have a limit in terms of the number of emails you can send per day.

  2. Be flagged as SPAM since large amounts of emails coming from a regular mailbox seem suspicious.

Gmail/GSuite and Office 365 (including Exchange) are the main players and are both supported by Overloop. You may also use your own SMTP/IMAP server.

What ESP should I choose?

The reliability of an ESP depends on the reputation of the IP addresses and domains of their customers. If you communicate through a shady ESP, you’ll be associated with shady IPs and domains, and your e-mails will more than likely end up in junk folders.

For that instance, we strongly recommend using the paid version of Gmail in GSuite. Let’s just say that Google’s reputation is, you know, pretty good.

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