top of page

Email Deliverability 101

For every $1 you spend on emails, returns can be as high as 4200%. So, evidently, email is hard to dismiss. That being said, this doesn’t guarantee the success of your outbound email campaigns. It depends on several metrics, one of them being a highly critical one that most sales and marketing people omit — email deliverability.

After all, you can only generate leads, convert clients, or even take ahead your communication with the prospect if your email actually reaches their inbox.

At The Scalelab, we send thousands of emails (with an average open rate of 85%). So, here’s giving out everything we know about email deliverability. In this article, you’ll know:

  • Why your emails might not be getting delivered?

  • How to avoid the spam box (and make sure your mail reaches your prospect’s inbox)?

  • The Golden Rule 🔑

  • Free Tools to test Email Deliverability

What is Email Deliverability & Why Should You Care?

Email Deliverability is at the crux of your outbound email campaign and largely determines its success. Got an email successfully delivered? Say hello to...

✅ more business opportunities

✅ more website traffic

✅ more leads

✅ and more conversions

On the other hand, if your email lands up in the spam box, besides the obvious loss of business, it also deteriorates your sender reputation.

Email Service Providers (like Gmail, Yahoo, Outlook, etc.) use sender reputation as a basis to decide whether an email is coming from a credible source and is worth reaching the recipient’s inbox or whether to flag it as spam.

Email Deliverability metrics sets the tone for your complete email campaign.

Your email open rate and reply rate are directly based on email deliverability. And if right now, while reading this line, you don't know what your deliverability rate is… then you most likely have a problem that you're not aware of.

Interestingly, most sales and marketers rarely check their deliverability rate. It's fully omitted, and they rarely speak about how many emails are actually getting delivered. Which is a little ironic — because if you're aware of it, you increase your chances for all the next steps :)

Why Your Email Might Not Be Getting Delivered?

Email communication looks quite simple. You send a mail, it gets delivered, the prospect opens it, and voila! In reality, out of every 100 outbound mails you’ve ever sent, about 12 of them probably missed the inbox.

The Hurdles

Internet Service Providers (ISP) → Spam Box → Junk Mail Folders → Blocklist

💀 The most dreaded of all is the Spam Box because it severely damages your reputation as a business and your future campaigns.

Take note, if your domain health is bad and you send 100 emails, 0 will reach your prospect's inboxes. And if you're not aware of this, it's even worse. But you can fix it!

So much with growing your business… 😅

lemwarm emails landing showing 100% "Spam" metric

Why Email Go To Spam Instead Of Inbox?

  • No Custom Authentication

ISPs use several authentication protocols which tell the system that you are credible. These are set up by the IT team or the email marketing platform you’re using. Failing to abide by these protocols increases the chances of emails going to spam.

  • Using Free-domain Address

Needless to say, ISPs prefer paid business domain addresses ( to free domain addresses (

  • Non-Credible IP Address

The IP address of the email marketing service you use also impacts the email deliverability. If your IP address has previously been used for spam, the ISP detects it and sends all the future emails to spam as well.

Note: This is possible even if you didn’t send a spam message yourself. If anyone else has used your IP address for the same, it may be flagged or blacklisted.

  • Spam Trigger Words

ISPs have a super-long list of fishy words that are common in most spam mails. Using them in your email (even unintentionally) is a big no. Some of these words include:

- Clearance

- Order

- Make $

- Beneficiary

- Discount

- Money-back

- Miracle

- Increase traffic/sales

Check the detailed list of spam-triggering words to avoid here.

  • No Unsubscribe Button

Cold outreach emails without an opt-out/unsubscribe link? That’s at best, annoying, and at worst, capable of sending you to the spam box.

  • No Permission to Send

If recipients didn’t give you explicit permission to clutter their inbox, they’re very likely to hit the spam button. It happens in the case of cold emails or unverified paid email lists.

  • Mail Blasting

If you’re sending out 1000s of emails in a split second, ISPs smell the spam from afar. Thus, bulk emails without a proper email service provider is a bad worst idea.

  • Wrong Target Audience

Your emails are not targeting the right set of people i.e. your emails are not relevant to them, and thus, people report your mail as spam.

5 Ways To Improve Email Deliverability (+ A Golden Tip!)

1. Use a Trusted IP Address

If you’re using an email marketing service, you’re on a shared IP address. If other customers of the same email service have blasted emails in the past, then the ISP will identify the entire server as spam and any email you send from it will be flagged or blacklisted.

We recommend using trusted platforms for sending your emails like:

2. Optimize the Email Body Copy

Your email copy says A LOT. 69% of email recipients can use the subject line to tell if it is spam. Follow this checklist to optimize your email copy for maximum deliverability:

✅ Make your subject line clear and hyper-relevant to your email content.

✅ Include Alt texts to all the images you include in the email.

✅ Have a clear CTA with links that lead to secure websites.

✅ Send emails from a credible company name and email ID.

❌ Avoid Spam-triggering words anywhere in the email.

❌ Do not include any hidden links/text in the copy.

3. Maintain Good Email Data Hygiene

Monitor your CRM and audit your contact list regularly. Look out for these emails addresses and remove them from the main list:

  • Hard-bounced email IDs

  • Zero engagement customers

  • People who unsubscribed

  • Email IDs with typos (

  • Duplicate email IDs

Did you know — Every time an email bounces, it affects your domain reputation. So, if you see an email bounce, make sure to remove it immediately from your list and don’t re-email them again.

4. Prevent Email Spoofing & Follow ISP Protocols

According to Google, Email spoofing is:

“Spammers can forge your domain or organization to send fake messages that appear to come from your organization. This is called spoofing. Spoofed messages can be used for malicious purposes, to communicate false information, or to trick people into giving out sensitive information.”

Follow ISP protocols to authenticate your domain address and prevent email spoofing. It includes:

  • Sender Policy Framework (SPF)

SPF protects your domain from spoofing and ensures that your emails are delivered to the sender correctly. It also prevents your emails from your domain from being delivered to spam.

  • Domain-based Message Authentication Reporting & Conformance (DMARC)

It helps the mail administrators prevent hackers and phishers from spoofing an organization or domain and lets you request reports from email servers that get messages from your organization or domain.

  • DomainKeys Identified Mail (DKIM)

It adds an encrypted signature to the header of all outgoing messages. Email servers that get signed messages use DKIM to decrypt the message header and verify the message was not changed after it was sent.

Complete domain authentication and get your domain verified by your email service provider (ESP). Your ESP will provide you with DNS records that you will have to add with your domain registrar. Taking this extra step ensures that your email is secure and not blacklisted.

5. Low Volume, High Quality

During initial contact with the prospect, it’s best to keep the email frequency low. Focus on quality instead of quantity. Avoid sending multiple emails without valuable or relevant content. Strive for engagement because it ultimately builds up your sender reputation and helps in customer acquisition.

And finally…


The best way to avoid being blacklisted is…


Stop blasting 2000 emails every day (courtesy: paid email lists).

Because [1] it kills your chance of building a meaningful relationship with your customer. And [2] ISPs flag your domain as spam and that’s a dead-end.

Internet Service Providers (ISPs) wage a serious war against spammers and they identify all of the above behaviors. It’s lethal! ISPs have a DNS-based blacklisted email list based on past activity. And you want to avoid getting into that at all costs. Check whether you’ve been blacklisted here.

Are Your Emails Getting Delivered? Here’s How to Check!

Emails might get delivered but land in the junk mail, promotions, or social folder. That’s as good as unsent emails. Your ultimate email deliverability goal must be Inbox Placement. It means optimizing your emails to reach the ‘primary’ folder, get read, and replied.

To check whether your emails are being properly placed in the inbox, follow these tips:

  • Measure the Post-Send Analytics

Low or negligible open rates may indicate that your emails aren’t visible to the recipients. It means it’s either in the spam or landed in junk mail folders despite being delivered.

  • Send Test Mails

Precaution is always better than cure. Cliche. But very true. So always test the deliverability of your emails with spam-testing tools like:

  • Use Email Tracking Tools

Monitor the email campaigns for existing subscribers and note whether your email was successfully delivered and the path it followed. Use tools like:

7 Free Tools To Test Email Deliverability

  1. Litmus: To test emails on several parameters like content, links, CTAs, etc.

  2. MX Toolbox: To check the validity of domain authentication protocols

  3. NeverBounce: To verify emails on your list and ensure that they won't bounce

  4. MailTrap: To test email against common blacklists to check whether it’s deliverable.

  5. To test the spamminess of your email

  6. GlockApps: To note ISPs, DMARC analysis, and other testing.

  7. SendForensics: For pre-send email optimization and post-send analytics.

Wrapping It Up…

Emails that do not reach your prospects’ inbox, won’t get read. Email deliverability is the bedrock for every email campaign. Strive to achieve email deliverability above 80%.

Summing it up:

  • Use creative, catchy, personalized subject lines — without any spam-trigger words.

  • Track post-send analytics and alter your mail list accordingly.

  • Do not send 2000 emails 🚨

  • Use trusted IP addresses, ISPs, and email providers.

  • Test your emails before sending with the tools mentioned above 👆🏼

Keep the above-mentioned tips in mind to avoid being flagged off as spam, and ensure that your email reaches its right place. The rest depends on how well you work towards communicating with your customers. Be human, strive to engage, and your emails will work as the best lead generation tools for your business.

And… if you need any support in lead generation via emails, we’re just an email away 😉

Over to you, Scaler !

Signing off,

Team The Scalelab

182 views0 comments


bottom of page