Email Deliverability Strategies to Stay Out of Spam

Email deliverability remains one of the biggest struggles for marketers, as they need to ensure their emails comply with the CAN-SPAM Act and other regulations while keeping their contact lists consistently updated with relevant contacts who’ve opted into campaigns.

In this blog, Joel Staniszewski, Lifecycle & Email Marketing Strategist, email marketing expert, will discuss ways to improve email deliverability, including various email deliverability tools and best practices that can help you land in people’s inboxes more consistently.

My Expert Opinion on Email Deliverability

Many businesses still have to deal with various email deliverability issues that hold them back. Today, around 64.6% of businesses state that poor email deliverability has hurt their revenue and customer retention, while a mere 23.6% of companies actually verify their email lists prior to launching a campaign.

If you’re not developing an effective email marketing strategy, you’re going to have a hard time avoiding spam folders and ensuring people see your emails with every campaign.

What is Email Deliverability?

In short, email deliverability applies to the ability for your emails to reach recipients after sending them. If you want to know how to improve email deliverability, the key is identifying the specific causes of email deliverability issues. From there, you can determine the email deliverability best practices and solutions to help optimize it.

Symptoms of Spam Issues

Before you can improve email deliverability, you need to know if your emails are going into people’s spam folders.

There are several signs that your emails are going straight to spam, including:

• A Drop in Open Rates: If you see a drop in email open rates, this is often the most obvious indicator that your emails aren’t finding their way into people’s inboxes, as your emails reach fewer recipients.
• Spam Folder Reports: You may also see that people are reporting your emails as “junk” or “spam,” with a high complaint rate signifying that your recipients aren’t receptive to your emails despite seeing them.
• Warnings in Postmaster: Another sign of spam-related email deliverability issues is a warning in Google Postmaster Tools, which could indicate sender reputation, delivery errors, and spam rates.

Root Cause Framework to Identify Email Deliverability Issues

In learning how to improve email deliverability, here is a framework comprising five main buckets to determine precisely what’s going wrong with your campaigns:

1. Authentication and Infrastructure

Two of the first items to consider when talking about email deliverability best practices involve authentication and your email system’s infrastructure. Here are some instances that could indicate an issue with these aspects:

You’re Not Using a Business Domain

There are a number of reasons why you should use a business domain, only one of them being to keep emails out of your subscribers’ spam folder. Using a domain that says the name of your email service provider (ESP) is less reputable than one that says your business name, and your receivers’ ESP algorithms catch on to this.

It’s not just the domain you use, but how you use it. If you use a custom domain, this means having to authenticate your domain, too. Most popular ESPs use something called DomainKeys Identified Mail (DKIM) to authenticate domains and filter for spam.

Also, you need to consider SPF, DKIM, DMARC, and alignment, and how they factor into authentication.

• Sender Policy Framework (SPF) is a record appearing in a domain’s DNS listing the IP addresses that can send its emails
• DomainKeys Identified Mail (DKIM) refers to a cryptographic signature within an email’s header that verifies the signature
• Domain-based Message Authentication, Reporting, and Conformance (DMARC) is a specific policy extending on SPF and DKIM to indicate to receivers how to handle emails that fail the authentication process. DMARC policy options include:
  • p=none: This indicates that receivers should take no action when emails fail DMARC checks while still providing the sender with a report.
  • p=quarantine: This policy will indicate to receivers that emails failing DMARC checks are to go into quarantine by sending them into people’s junk or spam folders.
  • p=reject: If an email fails a DMARC check, this policy will simply reject the email to ensure recipients never receive it.
• Alignment, on the other hand, is the link connecting the sending address to both the SPF and DKIM checks. Here, the domain appearing in the “From:” header needs to align with the SPF domain and the DKIM signature.

Once you have your domain set up, map the domain to an IP address using a DNS record. For instance, www.example.com might connect to 192.0.2.1, which is a compatible IPv4 address. CNAME records could also connect one domain to another, e.g., blog.example.com to www.example.com.

How to fix it:

• Change to a custom domain using your business name.
• Use platforms like Mailchimp and GlockApps to check authentication.
• Use SPF, DKIM, and DMARC records for your website’s domain.
• Work with a reputable ESP.
• Validate your IP with commands like DNS Lookup or online tools such as ZeroBounce and Hunter.

You’re Not Getting Through Your Receiver’s Inbound Filter

As an email marketer wondering why are my emails going to spam? you’ll want to make sure you don’t have an inbound spam filter issue. Whoever is receiving your email — whether it be a large business, regular company or desktop user — may use an automated spam filter that gives each email a numbered score based on how likely it is to be spam. These could be in lieu of an ESP’s standing inbound filter.

In fact, your business may use its own inbound spam filter to keep your channels clean and secure.

There are three kinds of filters: Gateway, hosted and desktop. Desktop filters tend to be the most customized, so they can be tricky to maneuver.

How to fix it: 

• Set up appropriate email authentication protocols.
• Ensure your domain doesn’t appear on a blocklist.
• Maintain a consistent sending schedule and gradually warm up your IP.

2. Reputation and Sending Behavior

You must also consider email deliverability best practices for reputation and sending behavior, which could factor in issues such as:

Your IP Address Hasn’t Solidified Its Reputation

If your IP address was used for spam in the past, or you’re using a new IP address that has yet to prove itself to be reliable, you may have issues with your emails being marked as spam.

Keep in mind that IP reputation is different from domain reputation, but both work together for email deliverability. IP reputation refers to the reputation of your sending IP address based on email sending behavior, while your domain reputation applies to your website and is based on your site’s age, overall authority, and DMARC and DKIM consistency and compliance.

IP reputation will depend largely on sending patterns, such as your send volume consistency, authentication pass rates, engagement metrics, and bounce rate percentages.

Here are some steps for IP warm-up to help you boost your reputation:

1. Start by sending a smaller number of emails per day, ideally under 100, and send them to active subscribers.
2. Gradually and consistently increase your sending volume by a small amount.
3. Continuously monitor KPIs like click-through rate, open rate, and spam complaint rate (which we will get into below).
4. Adjust your campaigns based on the data collected and progress toward goals.

How to fix it:

• Determine if you’re using a dedicated (private) or shared IP address.
• Eliminate senders on your IP that have sent any spam or engaged in fraudulent sending activity.
• If you have a new IP address, start with smaller amounts of emails before building up into a large-scale campaign.

You Have a High Spam Complaint Rate

If a lot of people are reporting your emails as spam, ESPs are going to algorithmically assume that’s where you belong. There are a lot of ways to avoid this — many of which we discuss throughout this blog — but we’ll give you a rundown here.

The ideal spam complaint rate is less than 0.1%, which indicates that your emails come across as valid and authentic.

How to fix it:

• Make sure your subject line and copy are accurate and intriguing.
• Send emails consistently, but keep the frequency on an even keel.
• Make sure you include an unsubscribe button and always get permission via opt-ins before sending someone an email.
• Regularly tidy up your subscriber list.

Your Sending Frequency Is Off

Email cadence is a dance. Too little emails and your audience will forget you even exist. Too many emails and you’ll annoy them (in fact, 78% of people unsubscribe because a brand sends them too many emails). Too inconsistent with your timing and you’re more likely to annoy people or catch them at a bad time.

How to fix it: Set a firm frequency and stick to it. Also, make sure you’re providing actual value within each message, otherwise your subscribers won’t be subscribers for much longer.

Your IP Is Appearing in Blocklists

If you haven’t built a good IP reputation and you get flagged for spam too often, you could appear in blocklists that keep you from sending emails entirely. This could be detrimental to your efforts and prevent you from reaching audiences.

You can use tools like MXToolbox and Spamhaus to see if your IP appears on any blocklists and on which databases.

How to fix it:

• Identify the appearance on blocklists and the root cause.
• Secure your systems and clean your email list.
• Request removal from the blocklist by contacting your provider after fixing the underlying issue.

3. List Hygiene and Consent

The people who appear on your email lists should be active subscribers who give you consent to send them marketing emails. The following are some issues to watch for and tips to prioritize opt-in email marketing for deliverability:

You Have a Low Open Rate

Without adequate open rates, the receiver’s provider will view your content as unreliable and, therefore, spam.

There are two parts to an open rate. The first is that the receiver clicks the email itself to open it. The second is that the reader opts to allow any images within the email to open, ultimately viewing the full email. If you’re not getting one or both of these, your open rates may be struggling and you could wind up in spam.

As of 2025, the average email open rate across all industries is around 42.35%.

How to fix it:

• Establish a cadence for cleaning your subscriber list, whether it’s every 30, 60, or 90 days of re-engagement.
• Detect spam traps by looking for signs like dropped open rates, unengaged subscribers, and surges in bounce rates.
• Segment your email lists to more effectively target the right people at the right time.
• Adjust campaigns to ensure you send during the right days and times for optimal engagement.
• Use double opt-in email marketing for deliverability, which involves a two-step subscription process to confirm interest.

This chart shows the days with the highest email open rates per industry.

You Didn’t Get Permission Before Sending Someone an Email

There’s nothing more annoying than landing on a subscriber list you didn’t choose to join. And quite frankly, you can’t blame people for hitting that unsubscribe or spam button with brute force when that happens. Adding people to your email list without their permission is tacky, and everyone knows it. It only makes sense this action would be a spam folder trigger.

If you’re purchasing email lists, this will hurt more than help your email campaigns. Not only will you be connecting with unengaged recipients who are more likely to drop you in their spam folder, but you also risk certain issues with GDPR, CAN-SPAM, and other regulations in place to mitigate the risk of spam.

How to fix it:

Always use opt-ins for your email subscription list. Better yet, use double opt-ins to ensure the folks on your list aren’t spamming you themselves, and to confirm they’re definitely interested.

You Haven’t Updated Your Subscriber List

Why are my emails going to spam, you ask? Old, dusty subscriber lists are no good in the email marketing world. If a lot of your emails are bouncing back because of incorrect or nonexistent email addresses in your list, consider removing them. This is one method for how to stop emails going to spam.

Over time, you may also find people on your subscriber list who never open or engage with your emails. This only hurts your metrics, which is another thing that can turn your content into spam.

How to fix it:

• Every so often, remove folks who don’t open or engage with your content.
• Regularly eliminate incorrect or nonexistent emails — trust me, they do you no good.

4. Content and Design

You should also keep in mind the content of your email, its layout, and visuals. The way your emails look will impact everything from whether people open your emails to engagement and conversion.

Here are some symptoms of low-quality content and poor design:

You Have a Low Engagement Rate

Getting your receivers to open your email is one thing, but what about engagement? ESPs use engagement rates as a strong indicator on whether or not your emails should go to spam.

Yes, this includes your open rate, but there’s more involved. Engagement includes the time your recipients spend reading your content and whether they click through any links within the email.

Also, make sure your text/HTML ratio is good and makes optimal use of content, and avoid using excessive punctuation or commercial words that might turn people away.

How to fix it:

• Increasing email engagement is a multifaceted task. First, focus on your copy — because if everything from your subject line to your closing CTA isn’t up to par, people won’t respond.
• Try split testing (AKA A/B testing) to confirm your copy is the best it can be.
• Conduct pre-send spam testing to further determine whether the email comes across as spammy.

Next, analyze when you’re sending your emails; the right day and time can make all the difference. You’ll also want to whittle down your subscribers based on which recipients no longer serve your metrics (it may seem counterintuitive, but it’s helpful to have the right audience, not just a large audience).

Two final action items to improve engagement and click-through rates:

1. Include a strong call-to-action above the fold, if the email warrants it.
2. Add captivating images with strong calls-to-action.

Your Unsubscribe Button Is Missing or Hard to Find

If you take anything from this list, make it this: You legally need to include an unsubscribe button in your marketing emails. It’s also good practice to make the unsubscribe button easy to find (this helps avoid frustrating your readers).

Even if it weren’t against the law, leaving out an unsubscribe button or making it hard to find is an ineffective email marketing tactic. You’re more likely to see high spam reports as a result, because if someone doesn’t want to be on your list, they’re going to get you out of their inbox one way or another.

How to fix it:

• Make sure you include an obviously placed unsubscribe button (most marketers include it near their business’ physical address at the bottom).
• Provide an opportunity for people to opt back in on a new window (you know, just in case).

If you want to reduce your unsubscribe rates, consider which days offer the lowest unsubscribe rates per industry.

Advanced Pro Tip: Consider using a different sender domain or ESP for transactional emails vs. marketing emails to avoid unsubscribe actions on your marketing email list affecting your transactional email delivery.

Unsubscribe rates by day and industry

Your Physical Address Is Missing

If you’re sending a marketing email as a business, it’s imperative to include a physical address. In fact, it’s the law (you can find more info in the CAN-SPAM Act from the FTC).

Brands typically do this all the way at the bottom, near the unsubscribe button. The address must be valid, whether it’s an office address or P.O. box. The reason for this is to make marketers traceable for the average consumer.

How to fix it:

• If you haven’t done it yet, implement a physical address into your template for all future email campaigns.
• If you’re a part of a small business or work out of your home, you should definitely get a P.O. box to keep your home address secure.

Your Subject Line Is False or Misleading (It’s Illegal!)

Here’s a quick — and completely avoidable — way to land in the spam folder. And even without spam reports and filtration, it’s an unethical marketing tactic that you should totally avoid.

In 2003, the US government made it illegal to intentionally mislead your email recipients through the subject line. The law is called the CAN-SPAM Act.

This can come to life in a few ways: Using a conversational subject line that makes it seem like you know the recipient personally (“want to get coffee soon?”), adding the word “urgent” when the email is anything but, and faking a purchase confirmation to get someone to open your email.

In 2019, Litmus and Fluent conducted a study asking people if they’ve ever felt deceived by promotional email subject lines. More than half of people, 54% to be exact, said yes.

How to fix it:

• Avoid misleading subject lines that use deceptive tactics like including an “Re:” in front or “Limited time” when an offer isn’t actually time-sensitive.
• Instead, opt for safe subject lines that clearly state the purpose of the email and its content, ensuring it’s relevant, e.g., “Update: New Features in Our App” and “Hi, [Name], Get the Perfect Tote Today!”
• Get creative with your subject lines without misleading audiences, possibly asking questions to invite people to learn more within the email itself.

Sorry, But You’re Forgettable

Even if the recipient gave you permission to email them in the past, and even if your email content is legitimate, you may still be wondering why are my emails going to spam?

The answer could very well be simple: They don’t remember you. As a result, they view you as a nuisance in their inbox, either deleting your email before opening it or incorrectly flagging it as spam.

How to fix it:

• Maintain a consistent theme and logo.
• Use a familiar typeface and color scheme.
• Find an email sending cadence that works for you.

All of this has to do with consistency, which undeniably contributes to recognition.

5. Mailbox Provider Rules and Monitoring

To even more effectively avoid spam folders, give ESPs specific rules for how to address emails marked as spam and consistently monitor your campaigns to gauge performance.

In the process, keep an eye out for the following issues:

Using Trigger Words

Most ESPs have constructed a list of spam trigger words to look out for when determining whether or not an incoming email is reliable. If you’re using any of them, you may be destined for the spam folder.

There are hundreds of keywords spanning various categories, including:

• lose weight
• billion dollars
• financial freedom
• sign up free today
• free installation
• risk free
• supplies are limited
• luxury car
• increase your sales
• passwords
• consolidate your debt
• no credit check
• compare rates
• earn extra cash
• order status

How to fix it:

• There are a number of cool tools (like EmailCopyChecker and ISnotSpam) where you can test out your email before sending it to actual people and determine if the language comes across as spammy — all based on popular ESP standards as well as average spam report rates.
• Alternatively, you can CTRL+F the most common spam trigger words for every email (or provide your copywriter with a list of terms to avoid to keep your workload down).

You’re Not Meeting Bulk Sender Requirements

Gmail, Yahoo, Microsoft, and other email providers have bulk sender requirements to help filter spam.

These requirements include SPF, DKIM, and DMARC protocols to authenticate emails, one-click unsubscribe links, proper formatting requirements, and spam complaint thresholds.

Google Postmaster Tools makes it easy to determine where your IP and domain stand among providers, with detailed instructions to help set it up.

Meanwhile, Microsoft SNDS provides insights into how Microsoft email services view your sending IP addresses, with information about spam trap hits, complaint rates, and other data. Here’s a guide on how to set this up.

Feedback Loop (FBL) services are also helpful and let senders know when people mark an email as spam. Google, Yahoo, and Microsoft all enable senders to set up these reports to help manage complaint rates.

How to fix:

• Meet bulk sender requirements as established by your providers.
• Set up feedback loops on all platforms.

When Learning How to Stop Emails Going to Spam, Is There a Difference Between Providers?

Every inbox provider has a unique spam filter. To avoid having marketers try to swindle the list, they don’t advertise their individual processes. It’s more of a trial and error thing. Use your email marketing software to analyze spam rates for different platforms. Consider segmenting your subscriber list based on the platform they use for their inbox so you can maximize your content’s chances of getting through the filter, no questions asked.

The “Why Are My Emails Going to Spam?” Question, Resolved

If you’re sending out emails to lift your brand, your content is probably going to hit the spam folder at some point. But by knowing how to stop emails going to spam, you can keep your levels to a minimum. This improves your standing with inbox providers and, most importantly, your subscriber list. And it keeps you in close proximity to your current or future consumers: Their primary inbox.

Advanced Troubleshooting

For more details about how to improve email deliverability, take the following key steps:

Contact Mailbox Providers

If you conduct any of the above fixes for specific identified issues and find that it doesn’t work, you could contact your mailbox provider for more assistance and guidance to fix deliverability problems. Zoho Mail, Gmail, Outlook, and other major providers typically offer support for business customers.

Run Speed Tests

Using solutions like Abstract API and Mail-Tester, you can conduct speed tests to determine deliverability rates. You might find that certain platforms are slower than others or that certain factors negatively impact your deliverability speed.

Measure Progress

Always measure the progress of your campaigns against your goals. Your goals will determine the marketing KPIs you set, whether you’re looking to maximize open rates, get more clicks, or drive conversions. Platforms like HubSpot and Mailchimp make it easy to track campaigns with rich analytics and reports.

Tools and Resources

There are multiple email deliverability tools you could use to help you maximize your emails’ visibility and reach, such as:

• Google Postmaster: If you want to find out how to test email deliverability, Google Postmaster Tools is one of the best solutions available, providing a rating for domain reputation, spam rate, authentication reports, and delivery error warnings.
• MXToolbox: As another of the best email deliverability services, MXToolbox can help determine whether your domain is blacklisted, conduct a detailed analysis of DKIM, SPF, and DMARC configurations, and review email content for certain types of spam triggers.
• Mail-Tester: A free-to-use email deliverability test tool, Mail-Tester can check the quality of individual emails before sending them to recipients, providing a spam score, technical and content review, and a blacklist check with valuable insight and feedback.
• GlockApps: For a more comprehensive email deliverability tool, you might turn to GlockApps, which provides a real-time deliverability report based on test emails sent to seed lists, along with HTML and content analysis, authentication monitoring, and actionable insights.
• Litmus: In addition to email design and preview capabilities, Litmus includes email analytics and spam testing features to help proactively address any issues before sending campaigns.
• Folderly: This AI-driven tool can diagnose and resolve email deliverability issues through content analysis to identify spam triggers, with the added ability to monitor email placement and complete email warm-up to boost your reputation.
• SendGrid: Twilio’s SendGrid is an email deliverability service that works specifically for marketing and transactional emails, with in-depth analytics, a powerful API, and various monitoring and optimization tools to improve deliverability.

FAQs

1. Why are my marketing emails going to spam instead of inbox?

There are several reasons why your email deliverability might suffer from spam-related issues, including spammy headlines that lead to reports of “junk” or “spam,” sending emails too frequently, non-compliance with the CAN-SPAM Act and other regulations, and generally poor design.

2. How do I test if SPF, DKIM, and DMARC are set up correctly?

You can conduct an email deliverability test by checking to see if SPF, DKIM, and DMARC are correctly set up using online checkers such as DMARCLY or EasyDMARC, along with sending test emails to MXToolbox or other email deliverability services.

3. What is domain warm-up and how long does it take?

This process, also known as IP warm-up, entails slowly and steadily increasing the volume of emails a domain sends to build the domain’s reputation over time. The process can take several weeks to develop a reputable domain that avoids winding up in spam folders.

4. What spam complaint rate should I aim for?

Generally, it is best to make your spam complaint rate as low as possible to avoid penalizing your domain, with the industry average usually falling around 0.1% or lower, which is approximately one complaint per 1,000 emails.

Learn How to Improve Email Deliverability With Ignite Visibility

To develop consistent, high-quality email campaigns that get real results, turn to Ignite Visibility for email deliverability services tailored to your needs. Our team of professionals has plenty of experience putting together high-performance campaigns that maximize visibility, open rates, engagement, and conversions.

Consider the following benefits of working with us:

• Fully developed email campaigns that avoid spam
• Well-constructed subject lines and content that engage recipients
• Compelling CTAs that drive action all the way to a sale
• Integration into a comprehensive digital marketing strategy
• And more!

Request a free proposal to get started with a custom email campaign for your business, and discover what we can do for you.