Why Gmail Spam Filtering Harms Your Employee Communication

Global researchers agree that email is one of, if not the most widely used tool used for communications, marketing, and organization in general. According to Statista, between 2019 and 2024, the number of global users increased from 3.9 billion to 4.4 billion. This number is expected to increase to 4.8 billion in 2027. 

Statista also reveals that more than 251 million emails are exchanged among global users every minute. This is five times as many instant messages that are exchanged. Furthermore, their statistics show that in August 2025, the U.S. was the country with the highest number of emails sent daily — on average 9.8 billion. Additionally, the U.S., together with China, was the country with the highest number of spam emails sent within one day worldwide in 2024 — each topping 7.8 billion. 

This sheer scale of email traffic is precisely why Google developed powerful Gmail spam filtering. With billions of messages moving across its servers every hour, Gmail’s algorithms continuously learn to detect phishing, malware, and bulk promotions. But while this keeps users safe and inboxes clean, it also increases the risk of legitimate internal messages being flagged as spam or routed to the Promotions tab.

Even the most well-crafted internal email won’t matter if it never reaches employees’ inboxes. Gmail’s powerful spam filters and Promotions tab are designed to protect users from unwanted marketing messages. But, in the process, they can also misclassify legitimate company communications. This becomes especially problematic for large all-staff sends, HR updates, or leadership announcements that get buried in the wrong folder or diverted to spam entirely.

For internal communicators, this hidden barrier can quietly erode engagement, trust, and alignment. Understanding how Gmail spam filtering works — and taking proactive steps to avoid it — is essential to ensure your messages land where they belong: in front of your employees, not lost in a spam folder.

How Gmail Spam Filtering Works

Gmail spam filtering is powered by machine learning models that continuously adapt to protect users from phishing attempts, junk mail, and unwanted bulk messages. These models evaluate billions of data points in real time, learning from user behavior and global email patterns to decide which messages deserve a place in the inbox — and which should be filtered out.

Every message is analyzed through several key criteria, including:

• Sender reputation: Gmail assesses the sender’s IP address, domain history, and authentication records (SPF, DKIM, and DMARC) to determine whether the source can be trusted.
• Message volume and frequency: Large or sudden spikes in outgoing email volume, or overly frequent bulk sends, may resemble spam-like behavior.
• Content triggers: Certain elements, such as promotional phrases, excessive links or images, and unfamiliar formatting, can raise red flags that result in filtering.
• Engagement signals: Gmail also considers how recipients interact with previous emails to gauge message relevance and credibility. Elements include opens, replies, deletions, and unsubscribes.

If a message doesn’t pass these primary inbox filters, Gmail automatically redirects it to the Spam or Promotions tab. This can happen even with internal or “all-staff” communications, especially if the send appears automated or overly promotional. 

Clean Email, founded in Ukraine in 2014, and now based in California, confirms that there were instances in 2024 when Google’s Gmail service incorrectly marked its own emails as spam.

“This might be due to individuals marking Google's emails as spam, leading Gmail's spam filter to incorrectly classify legitimate Google communications. Additionally, new emails with a gmail.com alias may sometimes bypass spam filters and be placed in the Primary folder until sufficient mark-as-spam behavioral data is collected.” Clean Email

For communicators, understanding these signals is the first step to preventing critical internal updates from being misclassified or overlooked.

Why Internal Communicators Struggle with Gmail Spam Filters

As mentioned above, even when emails are legitimate, Gmail’s machine learning models can mistake internal communications for external marketing. This happens because the same signals used to identify spam — message volume, content style, and engagement patterns — often overlap with how organizations distribute employee-wide updates. The result? Critical HR, IT, or leadership messages end up buried in the Promotions tab or filtered into Spam, reducing visibility and engagement across the workforce.

“All-Staff” Sends Look Like Bulk Marketing

Large-scale employee announcements may resemble newsletters or promotions from Gmail’s algorithm because they share many of the same traits as promotional campaigns. When thousands of identical messages are sent at once, Gmail’s system interprets them as bulk marketing activity. Even well-intentioned keywords like “announcement,” “survey,” or “reminder” can reinforce this classification, pushing all-staff messages out of the Primary inbox and into Promotions.

Lack of Authentication or Reputation

Deliverability depends heavily on technical trust signals. When messages originate from shared mailboxes or third-party email tools without proper authentication, Gmail may flag them as potentially unsafe. Missing or misconfigured SPF, DKIM, or DMARC records are common culprits, as they prevent Gmail from verifying that the sender is authorized to use the company domain. Without these safeguards, even genuine internal messages can appear suspicious.

Overuse of Images and Links

Internal emails are often designed like branded newsletters — visually polished, image-heavy, and filled with links to intranet pages or HR resources. While they may be visually appealing, this formatting can trigger Gmail’s promotional filters. Messages that rely more on HTML graphics than text, or that contain multiple links in close proximity, are often deprioritized or redirected to non-primary folders.

Employee Engagement Impacts Reputation

Gmail learns from recipient behavior. If employees frequently delete, ignore, or fail to open internal messages, Gmail is likely to interpret this as a sign of low relevance. Over time, this damages your domain’s sender reputation, making future emails even more likely to be filtered out. Consistent engagement — measured through opens, replies, or clicks — reinforces the legitimacy of your messages and helps maintain inbox placement.

Shared Domains Create Confusion

Many organizations send bulk messages from multiple departments, including HR, IT, and Marketing, all using the same company domain. Gmail’s filters can see this as a flood of high-volume outbound mail and may struggle to distinguish internal updates from external campaigns. When message frequency spikes or departments share overlapping audiences, Gmail may misclassify even internal communications as marketing traffic.

The Cost of Poor Deliverability for Internal Comms

When internal emails are trapped in Gmail’s Spam or Promotions folders, the consequences extend far beyond a few missed messages. Poor deliverability undermines communication reliability, disrupts employee alignment, and adds unnecessary workload to already stretched teams.

Missed emails can have serious implications. Compliance updates, mandatory training reminders, or time-sensitive crisis alerts may go unread, exposing organizations to risk and delaying critical responses. When employees repeatedly fail to receive or act on important communications, it risks erodes confidence in both leadership and the internal comms function. Over time, this breakdown in trust can foster disengagement and confusion — the very opposite of what internal communication is meant to achieve.

For internal communicators, the fallout is equally challenging. Teams often spend hours resending, troubleshooting, or manually following up to ensure key information reaches everyone. This reactive cycle drains productivity, inflates workload, and leaves less time for strategy and storytelling, which are the activities that truly build employee engagement.

How Can Users Improve Gmail Spam Filtering?

If you want to limit or avoid spam filters Gmail forces on you, there are options. 

While Gmail’s filtering system is largely automated, users can manually fine-tune it, though it will inevitably be time-consuming. Adjusting filters, marking messages, and managing spam folders all help train Gmail’s algorithm to better distinguish between legitimate and unwanted messages. However, for individuals or small teams, these manual actions can be effective, but they require ongoing attention and consistency.

Improve Filtering with User Actions

• Mark as spam: Train Gmail’s filters by manually marking unwanted emails as spam or selecting “Not spam” for legitimate messages that were incorrectly flagged.
• Block senders: Stop future messages from specific addresses by blocking them, sending all subsequent emails directly to your spam folder.
• Add to contacts: Add trusted senders to your contacts list so Gmail recognizes them as safe and prevents their emails from being filtered out.

Create Custom Filters

1. Click the gear icon in Gmail and select See all settings.
2. Go to the Filters and Blocked Addresses tab.
3. Click Create a new filter.
4. Enter criteria such as keywords in the subject line or body (e.g., “unsubscribe”).
5. Choose an action (e.g., Delete it or Skip the Spam folder) to apply automatically.
6. Click Create filter to save your rule.

Prevent Future Spam

• Don’t share your email publicly: Avoid posting your main email address on public sites, forums, or social media.
• Use a secondary email address: Create a separate account for sign-ups, subscriptions, or promotions to keep your main inbox clean.
• Use filters proactively: Set up keyword-based filters (like “unsubscribe” or “special offer”) to automatically move promotional emails or delete them.

For Administrators

Google Workspace administrators can use the Admin console to configure organization-wide spam filtering policies. This includes:

• Making Gmail spam filtering more or less aggressive depending on company needs.
• Quarantining suspicious messages for review before delivery.
• Bypassing spam filters for verified internal senders.
• Creating allowlists for trusted domains or addresses to prevent false positives.

Manage Spam Manually

• Report spam: For any unwanted message, click the Report Spam button (the exclamation mark icon) to help Gmail’s system learn.
• Block senders: Open a message, click the three dots beside the reply arrow, and choose Block [sender].

Unsubscribe safely: Use the Unsubscribe link at the bottom of legitimate marketing emails. If it’s missing or looks suspicious, avoid clicking other links in the message to prevent phishing risks.

How Cerkl Broadcast Solves Gmail Deliverability Challenges

To prevent Gmail from spam filtering internal emails, communicators can adjust send patterns, tighten authentication, and manually test deliverability. However, there’s a much easier and better way. Cerkl Broadcast is built specifically for reliable inbox placement and consistent employee reach, no matter how large or complex your organization is.

Built for Reliable Inbox Placement

Broadcast uses authenticated domains through SPF, DKIM, and DMARC protocols to guarantee trusted delivery from verified company sources. Its built-in email-sending infrastructure is already recognized by major email providers, including Gmail, which further enhances credibility and inbox priority. 

Unlike bulk marketing tools, Broadcast automatically classifies internal messages as priority communications — not promotions — helping ensure that employee updates, HR notices, and leadership announcements land directly in users’ primary inboxes.

Audience Management and Segmentation

Instead of sending blanket “all-staff” messages, Broadcast empowers communicators to target specific employee groups based on role, department, location, or interest. This dynamic segmentation ensures every message is timely, relevant, and personalized to each audience. By delivering only what matters to each employee group, Broadcast reduces bulk-send patterns, increases engagement, and strengthens overall sender reputation for more consistent inbox placement.

Personalization for Better Engagement

Cerkl Broadcast personalizes every message — from subject lines to content blocks — so employees receive communications that genuinely matter to them. When messages reflect the recipient’s department, role, or region, open rates naturally increase and engagement improves across the organization. These personalized touches reduce the appearance of bulk sends and strengthen your sender reputation, helping ensure consistent inbox delivery across all employee communications.

Send-Time Optimization

Broadcast’s AI-driven delivery optimization ensures each employee receives messages at the time they’re most likely to open and engage. This intelligent timing boosts open and click-through rates, strengthens engagement patterns, and helps maintain consistent inbox placement. Over time, these data-driven delivery insights build a reliable sender reputation and ensure critical internal messages are always seen when it matters most.

Measurable Deliverability Insights

With built-in analytics, Broadcast gives communicators a clear view of delivery success, engagement performance, and bounce rates. These insights make it easy to identify potential filtering risks early and continuously improve email health. By tracking and optimizing deliverability over time, teams can ensure that every message — from leadership updates to policy alerts — reaches its intended audience with confidence.

Gmail vs. Cerkl Broadcast: Email Deliverability Comparison

While Gmail is designed for personal and small-scale communication, it wasn’t built to manage enterprise-wide employee messaging. Cerkl Broadcast, on the other hand, is purpose-built for internal communication, ensuring that critical updates, announcements, and alerts are delivered reliably — not lost to Gmail’s spam or Promotions filters.

What’s Next

If Gmail spam filtering is limiting your reach, it’s time to modernize how you communicate internally. With Cerkl Broadcast, you can ensure secure, authenticated delivery to every employee inbox complete with real-time analytics, personalization, and AI-powered optimization.

Start segmenting smarter and communicating more effectively with our free Foundations Subscription Tier. You’ll get access for three team members, the ability to send up to 5,000 employee emails per month, and full use of Audience Manager, Email Builder, and Deliverability Analytics and other features.

Subscribe for free today. You won’t be sorry! 

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