Email deliverability: What it is and how to improve inbox placement

Email engagement doesn’t start with an open or a click — it starts with whether your message ever lands in the inbox. Even the best email can’t perform if providers filter it into spam or block it entirely. That’s the challenge of email deliverability: how providers evaluate your domain, authentication, reputation, and engagement signals to decide where your emails should go.

In this guide, you’ll get a clear, modern breakdown of how deliverability works in 2025, including the new filtering rules from Gmail and Yahoo, the metrics that actually matter, and the foundational steps every sender needs. You’ll also see how tools like monday campaigns use AI and CRM data to support healthy sending habits that strengthen inbox placement over time.

Key takeaways

• Poor email deliverability directly cuts your revenue by making you invisible to customers who want to hear from you — aim for 95% inbox placement to maximize your marketing ROI.
• Clean your email lists regularly, remove hard bounces immediately, and use double opt-in to maintain high engagement rates.
• Set up proper email authentication (SPF, DKIM, and DMARC) to prove you’re legitimate to email providers and hit inboxes consistently.
• Monitor your deliverability metrics beyond basic open rates by tracking inbox placement, spam folder rates, and provider-specific performance.
• Using AI, monday campaigns optimizes send times and segmentation while integrating with your CRM for superior list management, helping you rely less on separate deliverability tools.

What is email deliverability?

Email deliverability is your ability to land emails in subscriber inboxes instead of spam folders. Think about it this way: Sending an email is like mailing a letter, and delivery means the postal service accepted it. Deliverability means it reached the recipient’s mailbox, not their trash can.

According to email marketing research, 16.9% of all emails never reach the intended recipient’s inbox: 10.5% end up in spam and 6.4% go missing altogether as “undelivered.”

Strong email deliverability is built on several key pillars that work together to ensure your messages are seen. Understanding these components helps you diagnose issues and build a resilient sending strategy. Here’s what makes it work:

• Inbox placement: Your emails consistently reach the primary inbox.
• Sender reputation: Email providers trust you based on your sending history.
• Authentication: Technical verification proves you’re legitimate.
• Engagement: Subscribers open and click your emails regularly.

The science behind inbox placement

Email providers like Gmail and Yahoo use complex algorithms to decide where your emails land. These systems analyze your reputation, content, and predicted engagement in milliseconds.

The filtering happens automatically before anyone sees your message. Providers prioritize protecting users from spam, so they filter aggressively when they’re unsure about a sender.

Deliverability rate benchmarks

Here are some general email deliverability benchmarks:

• Over 95% is considered excellent
• Over 89% is considered good
• Below 80% is considered poor

These rates vary by industry and email type. Transactional emails like receipts typically achieve higher rates than promotional campaigns because subscribers expect them.

Additionally, 7 out of 8 emails sent are processed by Google, Microsoft, Yahoo and AOL (making up 87% of relative market share), and here are their deliverability rates based on research from EmailToolTester:

1. Google: 95.54% (57.8% arrive in the inbox; 37.74% arrive in the promotions tab)
2. Microsoft (Outlook and Hotmail): 91.33%
3. Yahoo: 81.33%
4. AOL: 76%

Email delivery vs. email deliverability

Email delivery and deliverability measure different things. Delivery tracks whether your email reached the server. Deliverability tracks whether it reached the inbox.

You can have perfect delivery with terrible deliverability. Your emails might reach Gmail’s servers but land in spam folders where no one sees them.

• Email delivery rate: Delivery rate shows the percentage of emails that reach mail servers without bouncing. This focuses on technical issues like invalid addresses or server problems. Hard bounces mean permanent failures from bad addresses. Soft bounces are temporary issues like full mailboxes that might work later.
• Email deliverability: Deliverability measures inbox placement quality. It tells you whether delivered emails actually reach where subscribers check messages. This metric is harder to measure but more important. It encompasses reputation, content quality, and engagement patterns that determine inbox placement.

Why both metrics matter

These metrics reveal different problems. High delivery with poor deliverability suggests reputation issues, and low delivery points to list quality problems. You can track both metrics through integrated analytics in smart software like monday campaigns and identify whether issues stem from technical problems or reputation challenges.

Why email deliverability matters for your business

Poor deliverability directly cuts your revenue. According to the State of Email report for 2025, when marketers spend $1 on email marketing, here’s what they experience:

• 35% receive $10-$36 in return
• 30% receive $36-50 in return
• 5% receive more than $50 in return

When your messages land in spam, the damage compounds quickly. Poor placement leads to lower engagement, which hurts reputation, which causes worse placement and ultimately impacts your email conversion rates. Breaking this cycle takes months.

Impact on ROI and revenue

Every point of deliverability loss equals lost customers. Dropping from 95% to 75% means losing one in 4 potential sales before anyone sees your offer. Recovery takes consistent good practices over months. During this time, your marketing stays compromised and revenue suffers.

Customer experience and trust

Spam folder placement damages brand perception. Subscribers expecting your emails think you’ve stopped communicating or question your legitimacy. Missing transactional emails creates immediate problems. Order confirmations and password resets in spam folders generate new support processes and frustrated customers.

Marketing campaign performance

Whether you’re running a drip campaign or a single promotional send, poor deliverability makes accurate measurement impossible. When audiences don’t see emails, your metrics don’t reflect true performance. This affects every marketing decision. You might cancel successful campaigns that appear weak due to deliverability, or continue ineffective ones because problems mask poor results.

Key factors that impact email deliverability

Several factors determine where your emails land. Problems in one area often trigger issues in others, creating cascading deliverability challenges. Understanding these connections helps you fix root causes instead of symptoms. Strong deliverability requires excellence across these 4 areas:

1. Sender reputation management

Your sender reputation works like a credit score with email providers. They track your IP address and domain reputation to decide inbox placement.

New senders start neutral and must prove trustworthiness through sustained good practices. Building reputation takes weeks of consistent volume and positive engagement.

2. Email authentication requirements

Authentication proves you’re who you claim to be. Major providers now require proper authentication for bulk senders — it’s mandatory, not optional, especially for mass email campaigns.

These protocols verify your identity and confirm emails haven’t been tampered with. Without authentication, legitimate emails get filtered or blocked.

3. List quality and engagement signals

Subscriber behavior directly influences deliverability through engagement signals providers monitor constantly. Providers analyze a range of subscriber behaviors to gauge engagement, which directly influences your sender reputation. These actions are categorized as positive, negative, or neutral signals. Here’s what they track:

4. Content and design best practices

Modern filtering focuses on relevance and value, not specific words, and well-structured HTML emails can further bolster your credibility. Providers analyze overall quality, mobile optimization, and subscriber response patterns.

The myth of “spam words” is outdated. Today’s filters prioritize whether subscribers find your content valuable and engaging.

How to check email deliverability

Measuring deliverability requires specialized platforms since providers don’t report inbox placement directly. Regular monitoring catches issues before they damage campaigns.

Early detection enables quick fixes that prevent reputation damage. The right platforms make this monitoring manageable and actionable.

Using Google Postmaster Tools

Google Postmaster Tools provides free Gmail deliverability insights. You’ll see IP reputation, domain reputation, and spam rates for the world’s largest email provider.

Key metrics include reputation scores from ‘Bad’ to ‘High’ and spam rates showing complaint percentages. These insights reveal specific improvement areas for Gmail delivery.

Email deliverability testing platforms

Seed testing sends your emails to test accounts across providers and reports placement. These services show inbox rates, spam placement, and missing emails, and you can combine this data with email A/B testing to optimize your campaigns.

Look for platforms offering real-time testing and comprehensive provider coverage. The best ones provide specific recommendations for improving placement.

Key metrics to monitor

Essential deliverability metrics provide deeper insights than basic open rates. Track these indicators for complete visibility:

• Inbox placement rate: Percentage reaching primary inbox
• Spam placement: Emails filtered to spam folders
• Missing rate: Messages that disappear entirely
• Provider performance: Results across Gmail, Yahoo, Outlook

With integrated deliverability monitoring and campaign analytics, monday campaigns provides complete email performance visibility from send to conversion.

Essential email authentication protocols

Authentication forms the technical foundation of deliverability. These protocols evolved from optional to mandatory as providers tightened requirements.

Major providers enforce authentication for bulk senders. Proper setup is essential for reaching any inbox consistently.

Here are the key authentication protocols you need to know:

• SPF (Sender Policy Framework): Lists which servers can send email for your domain — like a guest list telling providers who’s authorized to use your domain name.
• DKIM (DomainKeys Identified Mail): Adds digital signatures that prove authenticity and prevent tampering — like a wax seal showing your message is genuine and unaltered.
• DMARC (Domain-based Message Authentication): Tells providers what to do with emails failing authentication — you set policies for monitoring, quarantining, or rejecting unauthenticated messages.
• BIMI (Brand Indicators for Message Identification): Displays your logo next to authenticated emails in supported clients — while optional, it provides visual verification that builds trust.

7 email deliverability best practices

So, how can you proactively manage your sender reputation and ensure your emails land in the inbox? These strategies directly improve inbox placement by addressing core filtering factors. Each builds on others for comprehensive deliverability improvement.

Success requires consistent application over time. Focus on sustainable practices that scale with your email program, and explore how to turbocharge email marketing productivity with automation for greater efficiency.

1. Maintain clean email lists

List hygiene ensures you only email engaged, valid subscribers. Clean lists reduce bounces, minimize complaints, and improve engagement signals.

Remove hard bounces immediately. Monitor soft bounces and remove persistent failures indicating inactive accounts.

2. Implement double opt-in for deliverability

Double opt-in confirms subscribers genuinely want your emails. This leads to higher engagement and fewer complaints.

Confirmed subscribers engage more consistently. The quality improvement outweighs any list size reduction.

3. Segment your email marketing campaigns

Segmentation ensures relevant content that drives engagement. For B2B marketers, segmented emails result in 30% more opens and 50% more click-throughs, generating the positive signals that email providers value.

Dynamic email segmentation through CRM integration is enabled by monday campaigns, so segments update automatically based on behavior and preferences.

4. Optimize send times and frequency

Consistent schedules establish positive patterns while avoiding volume spikes that trigger filters. Find optimal frequency maintaining engagement without overwhelming subscribers.

Monitor when your audience engages most. Balance subscriber preferences with consistent patterns that build provider trust.

5. Create engaging subject lines

Subject lines driving opens improve deliverability through positive interactions. Focus on compelling, accurate representations of content.

Effective subject lines compound benefits over time and can significantly boost your email open rate. Test different approaches to find what resonates with your audience.

6. Monitor and remove inactive subscribers

Inactive subscribers hurt deliverability even without complaining. Providers interpret non-engagement as low value content.

Run re-engagement campaigns before removing subscribers. This protects reputation while giving subscribers chances to reconnect.

7. Use consistent sender information

Consistent ‘from’ names and addresses build recognition and trust. Changes confuse subscribers and appear suspicious to filters.

Establish recognizable sender identity. Consistency improves open rates and reduces complaints over time.

How to fix email deliverability issues

Deliverability problems need targeted solutions addressing specific root causes. Quick intervention prevents minor issues from becoming major reputation damage.

Focus on systematic improvements rather than quick fixes. Address underlying problems for lasting results, and consider implementing targeted email sequences to maintain healthy engagement.

Resolving high bounce rates

Rates above 2% indicate serious list problems damaging reputation, so monitoring your email bounce rate closely is essential. Hard bounces need immediate removal while soft bounces require monitoring.

Solution: Use validation services before adding addresses. Proactive verification prevents bounce issues and maintains quality.

Reducing spam complaints

Complaint rates above 0.1% trigger filtering and reputation damage. High complaints usually indicate targeting, frequency, or unsubscribe process issues.

Solution: Make unsubscribing obvious and easy. Simple opt-out processes prevent frustrated subscribers from using spam buttons.

Improving low engagement rates

Low engagement tells providers subscribers don’t value your content. Recovery requires improving relevance, timing, and deeper email personalization to re-engage inactive segments.

Solution: Create content driving specific actions. Clicks, replies, and forwards create stronger signals than opens alone.

Getting off blocklists

Blocklists severely impact deliverability across providers. Check listings regularly and follow removal procedures promptly.

Solution: Address underlying problems before requesting removal. Fix root causes to prevent re-listing.

Types of email deliverability platforms and software

Specialized platforms provide insights beyond basic email marketing capabilities. They focus on inbox placement, reputation monitoring, and authentication management.

Investment in proper monitoring prevents costly reputation problems. Choose platforms that match your program’s complexity and growth, such as a CRM with email marketing capabilities.

• Pre-send testing tools: Identify issues before launch by checking spam filters, authentication, inbox placement predictions, and content flags.
• Reputation monitoring tools: Track IP/domain reputation, blocklist status, complaint rates, and reputation trends across providers.
• Inbox placement and seed testing tools: Use test inboxes across Gmail, Yahoo, Outlook, and others to measure real inbox placement and spam filtering.
• Analytics and performance dashboards: Provide deeper insights into placement rates, provider-specific performance, and engagement patterns beyond basic open/click metrics.

How monday campaigns improves email deliverability

While monday campaigns doesn’t replace dedicated deliverability platforms, it strengthens inbox placement by helping teams follow sending best practices through CRM alignment, AI-driven optimization, and cleaner audience targeting.

Here’s how the platform supports stronger deliverability outcomes:

AI-powered content and timing optimization

AI helps teams send emails that subscribers are more likely to open — a key engagement signal providers watch closely.
monday campaigns uses AI to:

• Suggest optimal send times
• Personalize content based on CRM data
• Generate subject lines and copy that increase engagement

Higher engagement = stronger sender reputation over time.

CRM-synced segmentation and list hygiene

Because monday campaigns is built into monday CRM, your audience data stays clean and up to date automatically.
This prevents:

• Sending to inactive or invalid contacts
• Repeated bounces
• Unintentional over-messaging
• Poorly targeted campaigns

This CRM connection is the platform’s strongest differentiator — it helps maintain list quality at scale.

Integrated analytics for early issue detection

Core email performance metrics are centralized in monday campaigns so teams can quickly spot signs of deliverability trouble:

• Falling engagement
• Rising bounces
• Segment-specific drop-offs
• Changes in unsubscribe behavior

This visibility helps teams adjust before reputation issues escalate.

Seamless collaboration between sales and marketing

Because campaigns live inside the monday work management ecosystem, sales and marketing teams share audience insights and customer context. Better targeting leads to better engagement, which strengthens deliverability naturally.

By improving the parts of your email program providers actually evaluate — relevance, targeting, timing, segmentation, and list quality — and connecting your marketing data directly to your CRM, monday campaigns supports stronger inbox placement.

New deliverability rules from Google and Yahoo (2024/25)

Email providers have tightened filtering standards to reduce spam and protect users — and in 2024/25, Google and Yahoo introduced new requirements that affect all bulk senders. These rules now directly influence inbox placement, meaning compliance is essential for ongoing deliverability. Here are the key requirements:

1. Full authentication (mandatory for bulk senders): You must have the “big 3” authentication protocols set up and aligned: SPF, DKIM, and DMARC (at least p=none). Misaligned or missing records lead to filtering and blocking.
2. One-click unsubscribe: Bulk emails must include a one-tap (List-Unsubscribe) link, an unsubscribe process that takes two clicks or fewer, and removal within two days. This is now required for compliance.
3. Very low spam complaint thresholds: Both Google and Yahoo enforce strict complaint limits. Spam complaint rates must stay below 0.1%, even brief spikes can damage reputation and inbox placement.
4. TLS (encryption) required: Emails must be sent over a secure, encrypted connection.
5. Consistent “From” information: Senders must use a consistent “From” name and domain. Sudden changes appear suspicious and may affect inboxing.
6. Alignment between volume and reputation: Sending large volumes from a cold domain or inconsistent patterns triggers filtering. Warm-ups and consistent cadence are essential.

Why this matters for marketers

These rules make reputation, authentication, unsubscribe clarity, and engagement more important than ever. Marketers who don’t meet these standards will see deliverability drop — even with high-quality content.

Start improving your email deliverability today

Email deliverability isn’t a one-time fix — it’s an ongoing practice that separates successful email programs from struggling ones. The marketers who consistently reach inboxes treat deliverability as a fundamental skill, not an afterthought.

Start with the basics: authenticate your emails, clean your lists regularly, and monitor your metrics closely. Then build from there with segmentation, engagement strategies, and consistent sender practices. The right tools make this manageable by automating routine maintenance while surfacing the insights you need to stay ahead of issues.

Strong deliverability creates a foundation where your creative work, messaging, and offers actually reach the people who want to hear from you. When paired with solid CRM best practices, you’ll build an email program that grows stronger over time instead of fighting constant fires.