Divyanshi Sharma
January 3, 2025
Cold emails landing on spam?
Have you ever sent an important email only to realize it landed in the recipient’s spam folder?
It’s frustrating, isn't it?
And in the same time can cost your business a lot.
Email deliverability ensures your messages reach the inbox where they belong.
Whether you run email marketing campaigns or rely on cold outreach, mastering email deliverability can significantly boost your success by improving open rates and driving conversions.
Even if you're a seasoned marketer or just starting with cold email campaigns, this guide will simplify the complex world of email deliverability and help you optimize your email infrastructure for success.
Email Deliverability: Why It Matters
Email deliverability refers to the ability of your emails to land in the inbox instead of the dreaded spam folder.
The first 30% of success in cold email campaigns comes down to this factor.
Without high deliverability, your emails won’t even have a chance to be read, making it a critical element of your outreach strategy.
Causes of Poor Email Deliverability
There are several reasons your emails might not be reaching your recipients' inboxes. These include:
Low engagement rates: No replies or a high bounce rate.
Being marked as spam: If too many recipients report your email as spam, your reputation suffers.
Sending too many emails too quickly: Overwhelming your recipients can cause issues.
Using new or inactive domains: Sending emails from a recently created or dormant domain can trigger spam filters.
Key Factors Affecting Email Deliverability
To improve your email deliverability, understanding the following components is essential:
A. Sender Reputation: Your Domain’s Trust Factor
Your sender reputation is determined by both your domain and IP. Here’s a breakdown:
Domain Reputation: If you use a risky domain, like a .xyz or .online, it can lower your reputation.
IP Reputation: This is influenced by the email service provider (ESP) you use, such as Google or Microsoft. A poor IP reputation can negatively affect your deliverability.
B. Email Blocklists: Protecting Your Reputation
Email blocklists, or blacklists, prevent spam by blocking known offenders. Being on one can significantly hurt your deliverability. Regular checks on your domain and IP using tools like MXToolbox or SpamHaus can help keep you in the clear. Avoiding bad practices like buying email lists and ensuring engagement with your recipients are key steps to staying off blocklists.
3. Email Authentication: Proving Your Identity
Authentication protocols like DKIM, SPF, and DMARC verify the authenticity of your emails. This process protects against phishing and spoofing, ensuring that your emails are recognized as legitimate.
DKIM (DomainKeys Identified Mail):
Verifies that the email has been sent from the correct domain.SPF (Sender Policy Framework):
Ensures the sender is authorized to send emails from that domain.
DMARC (Domain-based Message Authentication, Reporting, and Conformance):
Protects your domain from being used in phishing attacks by aligning SPF and DKIM.
4. Inbox Warmth: Preparing Your Account for Success
Inbox warmth is about building your domain’s credibility with email providers. If your inbox is too new, sending a large number of emails can trigger spam filters. Warm-up your inbox gradually over at least two weeks to avoid this. Tools like Instantly, LemWarm, and Smartlead can help automate this process.
Crafting Emails That Get Delivered: Best Practices
Your email content is also a significant factor in deliverability.
Here are a few tips to ensure your emails don’t end up in spam:
Avoid spam trigger words: Certain words can make your email look like spam.
No all-caps: Writing in all caps can seem aggressive and spammy.
Limit special characters and emojis: These can be misinterpreted by email clients.
Stick to plain-text emails: HTML emails often have a lower deliverability rate.
Additionally, use Spintax to randomize your emails and avoid sending identical messages to multiple recipients. This helps protect your inbox from being flagged for sending too many similar emails.
Learn how to use spintax in your next email campaign here!
Handling Spam Complaints and Bounce Rates
One of the quickest ways to damage your sender reputation is through spam complaints. Always provide an easy opt-out method for recipients to unsubscribe without marking you as spam.
Using text-based unsubscribe options can increase your chances of avoiding a spam flag and improve your deliverability score.
How to Improve Email Deliverability?
Use Email Deliverability Testing Tools:
Use services like GlockApps, MailTester, and InboxAlly to check your inbox placement.Regular Health Checks:
Monitor open, reply, and bounce rates to detect deliverability issues early.Track Engagement:
Regularly update and segment your contact lists, removing inactive users or sending re-engagement campaigns.
Best ESP and Email Setup for High Deliverability
The choice of your Email Service Provider (ESP) plays a huge role in your deliverability rates.
Popular providers like
- Google Gmail
- Microsoft Outlook
These are widely trusted, but using both can provide better results than relying on a single provider. Pair these with warm-up tools like Instantly for the best results.
How to Recover from Email Deliverability Issues?
Pause Campaigns: Stop campaigns if deliverability rates drop.
Inbox Warm-Up: Re-warm inboxes for 5-7 days before resuming campaigns.
Domain De-Blacklisting: Consider professional help or contact blocklist services if your domain gets blacklisted.
It’s important to keep an eye on your deliverability rate and make adjustments as needed.
Sudden drops in open rates, an increase in bounce rates, or a lack of responses are all signs that your email deliverability may be suffering.
Regular checks, especially after large campaigns, will help you stay on top of any potential issues.
Frequently asked questions
1- What is the recommended number of emails to send per day per inbox?
The optimal number of emails to send per inbox is 30-50 emails per day. This includes a mix of campaign emails and warm-up emails to maintain healthy deliverability. A common split is 30-40 campaign emails and 10-15 warm-up emails. Maintaining this balance helps reduce the risk of being flagged as spam while ensuring consistent engagement.
2- Should I use Google (Gmail) or Microsoft (Outlook) for better deliverability?
It’s best to use both Gmail and Outlook. This is because emails sent within the same provider (e.g., Gmail to Gmail or Outlook to Outlook) generally have better deliverability compared to cross-provider emails (e.g., Gmail to Outlook). By using both platforms, you can maximize your reach and leverage the advantages of same-provider deliverability for each network.
For proper setup, ensure your domain settings (like SPF, DKIM, and DMARC) are correctly configured to avoid deliverability issues.
3- How do I know if my email might be blocked or suffering from poor deliverability?
Signs of poor email deliverability include:
A sudden drop in open or reply rates.
A sudden increase in bounce rates.
Poor results across multiple campaigns, such as minimal engagement.
Fewer responses than expected.
To prevent these issues, perform a weekly deliverability check to identify and resolve potential problems early.
4- Which email deliverability tester should I believe?
It’s recommended to cross-check results using multiple email deliverability testers. Start with free tools like Mailtester and MailReach for a quick assessment. If these tools indicate issues, conduct a deeper analysis with paid tools like GlockApps for more comprehensive insights.
Only after verifying results across several testers should you conclude whether your deliverability has declined. If problems are detected, pause all campaigns immediately to prevent further damage to your domain’s reputation.
5- Can I send outbound email campaigns to personal emails?
No, you should never send outbound email campaigns to personal email addresses. Personal email accounts (e.g., Gmail or Outlook for personal use) have stricter spam prevention protocols than business email accounts. Targeting personal emails significantly increases the likelihood of your messages being marked as spam and harming your sender reputation. Always focus on business emails for your campaigns.
6- Should I turn on or off open & reply tracking?
It is advisable to turn off open and reply tracking to improve email deliverability. These tracking mechanisms rely on HTML elements, which can trigger spam filters. Sending plain text emails (without HTML) generally offers better deliverability and reduces the chances of being flagged by email providers.
7- How can I de-blacklist my domain?
If your domain has been blacklisted, follow these steps to recover:
Pause all campaigns associated with the blacklisted domain immediately.
Let your inboxes warm up again for 5-7 days to rebuild trust and improve reputation.
Test deliverability after the warm-up period to ensure recovery.
Some domain blacklisters offer expedited removal through a donation or payment. Alternatively, you can hire a professional on platforms like Fiverr or Upwork to assist with de-blacklisting. However, the preferred approach is to allow a full warm-up cycle to naturally restore deliverability.
8- What is your recommended setup?
Here’s an effective setup for running a successful cold email campaign:
Email Service Providers (ESPs):
Email Warming & Campaign Management:
Tools for Testing Email Deliverability:
Tools for Checking Email Blocklists:
Pro Tip: Always use the same tool for both email warming and campaign management. This ensures that the warmup pool helps optimize your email deliverability.
Insider Tips for Instantly Users:
Open the “Campaigns” tab, select a campaign, and go to the “Sequences” section.
Find the first email variation and click “Preview.”
Choose the email address you want to test from the dropdown menu on the left.
Paste test email addresses into the “Send to” field.
(Optional) Enter test identifiers into the “Random Variables” field on the left if needed.
Final Thoughts on Email Deliverability
In the world of cold emailing, deliverability is the backbone of a successful campaign. By following best practices for email setup, content creation, and regular monitoring, you can significantly improve your chances of reaching your target audience.
Keep your emails clean, your domain healthy, and your practices in check, and you'll see better results in your outreach campaigns.
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