What Impacts Email Deliverability in Gmail?

Gmail rules the inbox game for both personal and business emails. But for email marketers? It can feel like trying to win a game without knowing the rules.

You’re doing everything “right,” yet your messages are still going to spam in Gmail. Sound familiar?

A lot of marketers are struggling with emails going to spam in Gmail, even when they follow best practices.

Here’s the deal: it’s probably not your content—it’s your email deliverability that’s getting in the way. And if you’re not paying attention to it, you’re making life harder than it needs to be.

Let’s fix that.

We’re going to break down what email deliverability really means, what Gmail looks for when filtering messages, and how an email deliverability tool can help you dodge the spam folder for good.

What is Email Deliverability?

Email deliverability is simple on paper: it’s about whether your emails land in someone’s inbox or get banished to spam. And no, it’s not the same as email delivery.

Just because Gmail receives your email doesn’t mean it ends up where you want it.

Deliverability looks at where the email actually lands. Inbox? Promotions tab? Spam? That’s what matters.

Gmail makes this trickier than most platforms.

Their filters use machine learning to figure out which emails people want to see—and which ones they don’t.

One wrong move (too many bounces, spammy words, low engagement) and suddenly, you’re ghosted by the inbox.

That’s why smart marketers are turning to email deliverability tools to see what’s working, what’s hurting, and how to improve their sender reputation.

Why Emails Go to Spam in Gmail?

Gmail’s filtering system is more than just a list of spam words. It considers sender behavior, user engagement, technical setup, and more. Here’s what commonly triggers Gmail’s spam filters:

A. Authentication Failures

Authentication protocols like SPF, DKIM, and DMARC are essential for proving your email is legitimate. Gmail uses them to confirm your identity as a sender.

If these aren’t properly set up, Gmail may flag your message as suspicious, even if the content is clean. This is one of the top reasons for poor deliverability.

B. Low Sender Reputation

Your sender reputation is a score that Gmail assigns to your domain and IP address. It’s based on your sending history, including engagement rates, spam complaints, and bounce rates.

New domains or cold email campaigns are more likely to trigger filters because they lack a history of trust. If too many people report your emails as spam, your reputation drops fast.

C. Spammy Content or Formatting

Your email’s design and content also matter. Things like keyword stuffing, deceptive subject lines, all-caps text, or missing unsubscribe links can all set off red flags.

Examples of what Gmail might filter:

• “Get rich fast!”
• Subject lines full of emojis
• No contact information or unsubscribe option

Even good content can land in spam if it’s formatted poorly.

D. High Bounce or Complaint Rates

Every time you send it to an invalid address, it bounces, and Gmail takes note. The same goes for user complaints.

If a high percentage of your emails get marked as spam, Gmail assumes your future messages are unwanted too. This is why list hygiene and permission-based sending are so important.

E. Inconsistent Engagement

Gmail tracks how recipients interact with your emails. If your messages get opened, replied to, or marked as “not spam,” Gmail considers them valuable.

But if users consistently delete or ignore your emails, your deliverability takes a hit.

Tip: Gmail updates your sender reputation in real time. One mistake can impact all your future sends—so it’s better to stay consistent.

F. Sending from Shared IPs or Low-Quality ESPs

If your email service provider (ESP) sends from a shared IP, your reputation is tied to everyone else using it. If someone else sends spam, you’re affected.

Cheaper platforms may not prioritize deliverability, either. Investing in a reliable ESP or using a dedicated IP can help reduce risk.

How Email Deliverability Tools Can Help?

So, how do you actually know where your emails are landing? And what can you do if your reputation is slipping?

That’s where deliverability tools come in.

A. What Is an Email Deliverability Tool?

An email deliverability tool is software that checks where your emails land: inbox, promotions tab, or spam folder. It also monitors your domain and IP reputation and tests your email content against common spam filters.

These tools are valuable for uncovering technical issues, content problems, and engagement trends—all things that affect whether Gmail sees your message as legitimate.

B. Top Capabilities of Email Deliverability Tools

The best tools give you a clear picture of what’s working and what’s not. Here are some features to look for:

• Inbox Placement Testing: The inbox placement test is crucial to see if your emails are landing in inboxes across Gmail, Outlook, Yahoo, and more.
• Reputation Monitoring: Track your domain and IP trust scores.
• Authentication Checks: Make sure SPF, DKIM, and DMARC are set up and aligned.
• Spam Filter Diagnostics: Test your content against known spam rules.
• Engagement Insights: Get data on opens, replies, and click-throughs.

C. How to Use These Tools Day-to-Day

It’s one thing to have an email deliverability tool, but it’s another to use it consistently. Here’s a practical workflow you can follow:

• Before sending: Run your email through GlockApps or MailTester to check for spam triggers.
• Weekly: Review your sender score and fix any issues with authentication or IP reputation.
• Monthly: Remove cold subscribers and analyze your engagement metrics.
• Quarterly: Audit your full setup—SPF, DKIM, DMARC—and ensure everything is still aligned.

Keep track of your changes, too. If a new CTA or subject line tanks deliverability, email deliverability tools help identify what went wrong.

Pro Tips for Avoiding Gmail Spam Filters

Beyond tools, here are specific steps to improve your inbox rate in Gmail:

A. Warm Up Your Domain

New domain? Start slow. Gmail needs to see a history of positive engagement.

Authentic tools can automate the warm-up process by sending small batches and gradually increasing volume.

B. Monitor Engagement

Clean your list regularly. Remove subscribers who haven’t opened or clicked in 60–90 days.

Segment your lists and personalize emails to boost response rates.

C. Authenticate Everything

Your domain must have SPF, DKIM, and DMARC records properly set up. They must also match your sending domain.

Test your configuration using deliverability tool of choice.

D. Avoid Spam Trigger Words

Certain words and phrases will hurt your Gmail deliverability. Examples include:

• “Free trial”
• “Limited time offer”
• “Earn money now”

Stick with honest, clean copy and avoid gimmicky subject lines.

E. Test Before You Send

Always test major campaigns with a deliverability tool. This gives you insights into inbox placement and content red flags.

You can fix issues before they affect your entire list.

The Bottom Line

Gmail’s spam filters are smart—and getting smarter. Success isn’t just about writing great content anymore. It’s about earning trust, staying consistent, and fixing technical gaps before they damage your reputation.

If you’re struggling with emails going to spam in Gmail, don’t leave it to guesswork. Use an email deliverability tool to understand what’s happening, fix what’s broken, and start getting results.

Take the time to audit your current setup. Make deliverability part of your long-term strategy, not just a quick fix. Because when your emails actually reach the inbox, everything else gets easier.