Gmail Deliverability Best Practices

Gmail is the most popular email provider out there, so you want to make sure your Gmail deliverability is the best it can be.
Gmail is the most widely used email provider by individuals and companies, with almost 30% market share.

For salespeople and marketers, Gmail is one of the leading ISPs they always need to reach. Other services may have additional issues or be less widely used, so running tests that reveal you’re hitting spam may not be as concerning.

The minute you learn your emails are hitting Gmail spam filters, it’s time to act.

In this article, we’ll review factors to consider when aiming for the Gmail inbox and best practices to follow when sending out your emails.

Factors That Affect Gmail Deliverability

Sender Reputation

Sender reputation plays a crucial role in determining whether an email will reach its intended recipient or end up in the spam folder. Both the sending domain and IP address are assessed by Gmail and G Suite to evaluate the trustworthiness of the sender. These platforms consider various factors to determine sender reputation, and positive engagement metrics are highly influential.

Positive engagement metrics include high open rates, which indicate that recipients are interested in and engaging with the emails they receive. Similarly, high click-through rates (clicks on links within the email) are also considered positive engagement metrics. On the other hand, if recipients frequently mark emails from a particular sender as spam or irrelevant, it can harm the sender's reputation.

When a sender's reputation is good, their emails are more likely to reach the recipients' inboxes rather than being filtered into spam folders or blocked outright. However, if a sender has a poor reputation due to sending spammy or irrelevant content, their emails are more likely to be filtered as spam or blocked by email providers.

Email Authentication

Email authentication is the process of verifying the authenticity of an email sender, ensuring that the claimed source indeed sends the email. It helps establish trust between the sender and the recipient, reducing the likelihood of emails being marked as suspicious or fraudulent. SPF, DKIM & DMARC are the way to authenticate your emails.

  • SPF (Sender Policy Framework): SPF is a widely used email authentication protocol that specifies which servers are authorized to send emails on behalf of a domain. It works by adding a DNS record that lists the authorized sending servers for a domain. When an email is received, the recipient's server can check the SPF record to verify if the sending server is authorized. SPF helps prevent spammers from forging the "From" address and improves the chances of legitimate emails reaching the inbox.

  • DKIM (DomainKeys Identified Mail): DKIM is another email authentication protocol that adds a digital signature to the email header. This signature is generated using encryption techniques, verifying that the email hasn't been tampered with during transit. The recipient's email server can use the public key published in the sender's DNS records to validate the DKIM signature. By implementing DKIM, senders can ensure the integrity of their emails and enhance deliverability.

  • DMARC (Domain-based Message Authentication, Reporting, and Conformance): DMARC is a policy-based email authentication protocol that builds upon SPF and DKIM. It allows senders to specify how email servers should handle unauthenticated emails. With DMARC, senders can set policies to either monitor, quarantine, or reject emails that fail SPF or DKIM authentication. DMARC also provides valuable reporting mechanisms to track email authentication and identify any unauthorized or suspicious activity associated with a sender's domain.

Email Content & Structure

When determining whether an email is legitimate or spam, Gmail's spam filters analyze multiple elements of the email, including:

  • Subject Lines: The subject line of an email is carefully scrutinized. It's important to avoid using deceptive or misleading subject lines that might trick recipients into opening the email or falsely representing its content.

  • Body Text: The email's body text is analyzed for various factors. It's crucial to avoid using spam trigger words or phrases commonly associated with unsolicited or fraudulent emails. These trigger words can include terms like "free," "guaranteed," "urgent," or "act now." Excessive capitalization, exclamation marks, or poor grammar can also raise red flags.

  • HTML Code: The underlying HTML code of the email is assessed. Ensuring that the HTML code is clean, well-formed, and adheres to best practices is essential. Poorly coded emails or the inclusion of suspicious elements can trigger spam filters.

  • Links: The links included in the email are examined. It's important to use legitimate and reputable URLs and avoid using link shorteners or URLs associated with known spam or phishing websites.

  • Attachments: Attachments are analyzed to ensure they don't contain malicious files or executable code. Certain file types, such as executable files or zip archives containing suspicious content, can raise concerns.

  • Overall Content: The overall content and structure of the email are considered. Emails with relevant and engaging content that resonate with recipients are more likely to be considered legitimate and have a better chance of reaching the inbox.

User Engagement

User engagement refers to how recipients interact with the emails they receive. Gmail considers user engagement as a crucial indicator of email quality when determining where to place incoming emails.

Positive user engagement metrics can have a positive impact on email deliverability. In contrast, recipients' low engagement or negative actions can affect the deliverability of emails, potentially causing them to be filtered or marked as spam.

Here are some key user engagement metrics that Gmail takes into account:

  • Open Rates: The open rate indicates the percentage of recipients who open an email. A higher open rate is generally seen as a positive engagement signal, suggesting that the email is relevant and intriguing to recipients.

  • Click-through Rates: The click-through rate (CTR) measures the percentage of recipients who click on links within an email. A higher CTR signifies that recipients found the content compelling enough to take further action, such as visiting a website or exploring more information. A higher CTR is considered a positive engagement signal.

  • Replies: When recipients reply to an email, it indicates an active and engaged interaction. Replies can include feedback, questions, or further communication. Encouraging recipients to reply and fostering two-way communication can contribute to positive user engagement.

  • Spam or Archive Actions: Actions taken by recipients, such as marking an email as spam or archiving it, also influence email deliverability. If a significant number of recipients mark an email as spam, it negatively impacts the sender's reputation and can lead to future emails being filtered or blocked. On the other hand, if recipients consistently archive emails from a particular sender without marking them as spam, it indicates positive engagement.

Monitor & Test Deliverability

The quality of your email list refers to the relevancy and authenticity of the subscribers on your list. It's crucial to build a high-quality list through permission-based opt-ins. This means obtaining explicit consent from individuals to receive emails from you.

Purchasing or using third-party lists often leads to low-quality subscribers who may not be genuinely interested in your content. Such lists can result in higher email bounce rates, lower engagement and potentially damage your sender's reputation.

Subscriber engagement measures how actively your subscribers interact with your emails. It includes actions such as opening emails, clicking links, replying to emails, and overall responsiveness.

High subscriber engagement is a positive signal to email service providers that your emails are wanted and relevant.
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How to Improve Gmail Deliverability

Avoid Spam Trigger Words & Images or Links

It’s come up in other articles in our blog, but you want to keep your email copy as clean as possible, especially if you are sending out a lot of cold emails.

Newsletters have more of a pass, but even then, you want to keep everything as clean as possible.

Avoid bolding or italicizing anywhere in your text, even your signature. Avoid hyperlinks and images, as well as attachments. All of these may trigger spam filters.

Authenticate Your Email Address

Take the step that spammers do not and verify that you are indeed who you say you are.

You do not want a spammer spoofing your address to send emails on your behalf; you also want only to receive legitimate emails.

By doing so, you demonstrate that you care about protecting your company and prospects, and Gmail’s filters will read your emails as legitimate and verifiable.

Warm-Up Your Email Address

Warming up an email address for email marketing, newsletters, or cold emailing with tools like can significantly improve deliverability to Gmail and G Suite recipients.

When you send emails from a new or inactive address, it lacks a sender reputation, which is crucial for email service providers like Gmail to determine the legitimacy of your messages.

Warm-up tools help build this reputation gradually by gradually increasing the sending volume, maintaining positive engagement metrics, and avoiding sudden surges that may trigger spam filters.

By following a warm-up process, you establish trust with email providers and demonstrate that your emails are wanted and relevant.

Check out our email warm-up guide to learn more.

Additionally, we provids testing and monitoring features to assess deliverability, simulate recipient behavior, and identify potential issues.

Keep Your Lists Clean & Validated

Going over your lead lists and ensuring that the emails are accurate and everyone still works there may take time. Still, it is essential to keep your email deliverability healthy.

The more unverified email accounts you send to, the more your email health score and your senders’ reputation will suffer. And the less likely you are to get through Gmail’s spam filters.

Take some time every week to check your lead lists to avoid falling into spam – it’s worth it!

Personalize Your Emails & Segment Your Audiences

Any sales professional worth your time knows this, but it is always a good reminder.

Personalize your emails and segment the messaging according to your audiences.

Don’t send the marketing and finance teams the same messaging – it will probably not work and it will harm your email health.

Spend your time on your research and email copy to provide value for different audiences that will interest them. Demonstrate your knowledge of the industry, its pain points, and how your product or service fits.

And use some humor to stand out while you’re at it!

Have a Dedicated Domain For Cold Emailing

A dedicated domain or address for cold emailing is a great way to generate cold seeding and manual email warm-up. It is also great for tools.

Should anything happen to its deliverability, you can keep an eye on it without harming your primary address or domain you actively use for internal or external purposes.


Gmail is far and away the most common email provider you will find, whether it is for individuals or companies.

You must ensure your emails are landing in Gmail's inboxes more than any other ISP.

Considering the factors outlined above and the best practices we’ve suggested, you will surely see success in your email campaigns.

Make sure also to be compliant with the latest Gmail requirements for mass sending.

Plus, you can always use Unfiltered to keep your Gmail deliverability in excellent shape!
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