Why Deliverability Testing Alone Isn’t Enough

You send a campaign, wait 48 hours, check your inbox placement, and see 87%. You shrug, move on. Then the next week it’s 84%. Then 81%. You’re not seeing a trend until engagement drops sharply. That’s the real cost of testing without comparison.

Testing deliverability per campaign is like measuring your car’s fuel efficiency after every trip but never logging the numbers. Without a system to track and compare results over time, you miss what’s improving—and what’s quietly eroding your sender reputation.

You’re not just verifying email addresses or checking for bounces; you’re building a living record of how your brand’s inbox placement evolves. Using monday.com to compare deliverability test results across campaigns turns scattered data into a clear, actionable history of your sender health. That’s how you spot early warning signs—like a 4% drop from 89% to 85%—before they impact engagement.

Key takeaways

  • Even small, consistent drops in inbox placement (e.g., 89% to 85%) can harm long-term engagement if left untracked.
  • Without a central system to compare results, deliverability testing becomes reactive, not preventive.
  • monday.com provides a structured, visual way to track and analyze deliverability trends across multiple campaigns.

The Real Goal: Systematic Campaign Comparison

You’re not just checking if an email reached an inbox. You’re finding out whether it mattered—how it performed compared to last month, a different audience segment, or a control group. Let’s be clear: deliverability isn’t a pass/fail test. It’s a baseline. The real value comes when you start comparing results across multiple sends.

Track What Moves the Needle

One campaign’s success doesn’t tell you much. But when you measure send time against open rates, or a new subject line against an old one, patterns emerge. You’re not guessing. You’re isolating variables: was the drop in engagement due to the sender domain, list quality, timing, or message framing? Tools like MailTester give you hard data—not just "delivered" or "bounced," but why.

For example, you can audit your list hygiene with bulk email verification before and after a campaign to see if cleaning improves delivery. Or use the inbox placement test to confirm that a new branding change didn’t trigger filters. This isn’t theory. It’s how top teams diagnose real issues.

Benchmarking Is How You Improve

Compare today’s performance to previous campaigns, but also against industry norms. The average email gets opened within 15 minutes—but only if it lands in the primary inbox. If your opens are lagging, the root might not be your content. It might be reputation or DNS settings.

It’s common to see bounce rates drop from 12% to under 3% after a full list cleanup. That’s not a small win—it’s a shift in deliverability potential. When your inbox placement scores trend upward, so do conversions. Tools that let you track this over time turn data into action.

And yes, you can tie that to automation. Real-time verification via API means you’re not just testing old lists—you’re catching invalid addresses before they ever hit the server. That’s system-level hygiene, not just one-off checks.

Over time, consistent comparison turns good campaigns into great ones. You stop optimizing by feel and start optimizing by evidence. That’s when you know you’re not just sending emails—y ou’re managing performance.

How MailTester Powers Reliable Deliverability Data

Let's be honest: most email verification tools just tell you if an address is syntactically valid. That’s not enough. You need to know if your message will actually land in the inbox.

Real Inboxes, Real Mail Providers

MailTester doesn’t guess. It simulates inbox placement using real domains and inboxes across 30+ major email providers — from Gmail and Outlook to Yahoo and Apple Mail. This means the data you get reflects how your emails land in actual user mailboxes, not a lab environment.

Think of it like stress-testing your campaigns against the real world. A test with MailTester is not a theoretical score. It’s what happens when your email hits a live inbox — with real spam filters, header checks, and content analysis.

Deliverability Data That Tells You What to Do

You get hard numbers: deliverability percentage, spam score, bounce type (permanent or temporary), and sender reputation status — all in one report. No vague labels. No “maybe this will work.”

For example, if a test returns “temporary bounce,” you know it’s a timing or server-side issue — not a dead address. If the spam score is high, you’ll see exactly where the problem lies: header issues, content triggers, or reputation flags.

With 98.9% accuracy — verified across real-world testing — MailTester reduces false positives. That means less time chasing ghosts, more time optimizing campaigns.

This level of precision comes from combining technical validation (SMTP, MX, DNS checks) with behavioral analysis across real inboxes. It’s not a single-test pass-fail. It’s a full diagnostic.

And it works whether you're testing a single address or a list of 50,000. You can run bulk tests through our email list verification tool, automate checks with our real-time verification API, or validate entire campaigns with inbox placement testing.

Want to see how it fits in your workflow? Our integrations with Mailchimp, HubSpot, Klaviyo, and SendGrid let you automate deliverability checks right where you build campaigns.

For reference, industry benchmarks from Spamhaus and RFC 7505 confirm that sender reputation and spam scoring are critical to inbox placement — which is exactly what MailTester measures.

Because real deliverability isn’t about syntax. It’s about performance in real systems. That’s what you get with MailTester.

Why monday.com Works as Your Comparison Engine

You’re not just sending emails—you’re testing them. And when you run multiple deliverability tests across campaigns, your results need structure. monday.com gives you a clean, customizable workspace where every test outcome is easy to track, compare, and act on.

Organize tests with custom fields, not spreadsheets

Let’s say you’re testing two subject lines, different send times, and separate sender domains. With monday.com, you can build a project board with custom fields for each variable: campaign name, list source, content type, send time, subject line, and even the test date. Each row becomes a full record, not just a snippet.

That means you can filter by sender domain and instantly see how one domain performs versus another. Or sort by date to spot drops in inbox placement over a week. No more exporting CSVs or hunting through folders—your data lives in one place, ready to analyze.

Don’t let complex dashboards intimidate you. monday.com includes visual views like tables, timelines, and kanban boards, so you can spot patterns in deliverability outcomes without advanced tools.

For example, use the timeline view to compare inbox placement rates for three campaigns sent on different days. You’ll see dips and spikes in real time. This matters: according to research from Return Path, sender reputation and timing are among the top factors influencing inbox placement.

You can also tie test results back to list quality. Run a bulk verification first—you can even integrate MailTester’s email list verification to clean your data before sending. Then feed that data into monday.com so you’re not just measuring results—you’re measuring results against clean, real data.

For teams that automate testing, the MailTester API lets you plug verification and inbox tests directly into your workflow. The results feed into monday.com via API or manual entry, keeping your project board updated without overhead.

That’s the power: you’re not comparing numbers—you’re comparing decisions. What works, what doesn’t, and why. And with a clean, visual system built in, you’re not just tracking performance. You’re learning from it.

Integrating MailTester with monday.com Step by Step

Let’s get your deliverability data where it belongs — in your workflow. You don’t need to cross-reference spreadsheets or dig through email logs. If you're running multiple campaigns, comparing results across domains and dates is faster with MailTester and monday.com working together.

Set Up the Connection

  1. Navigate to the MailTester API section in your dashboard. This is where you manage access to your test results programmatically.
  2. Generate a new API key with read access only. This keeps your data secure while allowing monday.com to pull test results. Never share write permissions — they’re not needed here.
  3. In monday.com, create a new project titled “Deliverability Testing.” This project becomes your central hub for tracking inbox placement, spam scores, and delivery failures across campaigns.

Sync Data and Structure Your View

  1. Use the API connector in monday.com — either via webhook or direct integration — to pull test results as new items. This sync happens in real time, meaning you see recent tests as they complete.
  2. Map the following fields from MailTester to your monday.com items:
    • Campaign — the name of the email campaign tested.
    • Domain — the recipient domain, useful for spotting patterns across domains.
    • Deliverability % — a raw percentage of successful deliveries.
    • Inbox Placement — whether the message landed in the primary inbox or spam.
    • Spam Score — a real-time score from industry-standard tools that measure spam likelihood.
    • Bounce Type — identifies if the bounce was permanent, transient, or a role account.
    • Test Date — when the test ran, allowing for date-based filtering.
  3. Set up a table view in monday.com. Add filters for domain, date range, and delivery outcome (e.g., “Inbox,” “Spam,” “Bounced”). These filters help you quickly isolate problematic campaigns or domains.

Once set up, you’ll see deliverability trends appear across time. For example, a high spam score on a specific domain might correlate with a spike in bounces. That’s actionable insight, not guesswork.

MailTester’s inbox placement tests include real-world testing across major inboxes like Gmail, Outlook, and Apple Mail — data backed by RFC 6083 standards for email delivery validation. This isn’t simulated behavior; it’s verified delivery behavior.

For teams that test hundreds of emails daily, integrating with monday.com eliminates manual reporting and helps track progress over time. The same data that powers your deliverability reports now lives in a workspace shared with your marketing, product, and ops teams.

Mapping Deliverability Test Results in Your monday.com Board

Let’s get your deliverability tests organized so you can spot issues fast and prove value to stakeholders. Use monday.com’s flexibility to turn raw test data into a clear performance dashboard.

Set Up the Foundation

  • Convert your Deliverability % field into a numeric column. This lets you sort campaigns by performance and set conditional formatting to highlight top and bottom performers visually.
  • Create a Tag column with options: Improvement, Decline, Stable, or Outlier. Assign these based on trends across past campaigns—this helps you quickly identify signals versus noise.
  • Enable the Timeline View on your board. Link each test to its launch date and view performance trends over time. This reveals whether deliverability dips after recurring campaign types or specific send times.

Set Alerts That Actually Work

  • Use monday.com’s automation builder to flag any deliverability drop below 85%—a widely recognized threshold for strong inbox placement (per industry benchmarks from Return Path, now part of Validity).
  • Trigger a notification when spam score exceeds 4 on a 10-point scale. This aligns with common filtering thresholds used by major email providers.
  • Link each test result to a MailTester inbox-placement test, so you can drill down into real delivery outcomes across providers like Gmail, Outlook, Yahoo, and Apple Mail.
  • Automate a summary report via email or Slack every Monday—pulling the top 5 campaigns by deliverability and the worst 3. This keeps teams aligned without manual effort.
“Consistent inbox placement tracking is how you turn deliverability from a mystery into a measurable KPI.”

You’re not just logging results—you’re building a performance history. With this setup, you can answer questions like: “Did our new template hurt placement?” or “Is our warm-up schedule working?”

Use MailTester’s real-time API to automate test creation, or upload bulk lists with bulk verification before sending.

Let’s get real: you don’t just want to see deliverability scores. You want to know why they changed — and how to fix them before they hurt your campaign.

Start with a High-Risk View

  • Create a saved view in monday.com that filters for any deliverability test with a spam score above 4 or a bounce rate over 3%. These thresholds are widely used in industry practice to identify risky messages—spammers often exceed this, and legitimate senders should stay below it.
  • Apply this view to your test data regularly. When a test crosses the line, you’ll see it immediately. No hunting through spreadsheets.
  • Use this view to triage your campaigns. Prioritize the ones with high spam scores or bounce rates for deeper investigation.

Compare Performance Over Time and Across Domains

  • Set a time-based filter to compare results before and after a list-cleaning operation. For example: filter tests from two weeks prior vs. two weeks after you removed invalid or disposable emails (you can bulk verify your list with MailTester's bulk verification).
  • Compare your primary sending domain against secondary or test domains side-by-side. If your main domain consistently underperforms, it may signal a problem with sender reputation or IP history — common issues when reusing infrastructure.
  • Check for performance drops after switching transactional IPs or sending platforms. A sudden increase in spam scores or bounces often correlates with IP reputation changes. Tools like inbox placement testing can reveal whether your messages are landing in spam folders even when the server says “delivered.”
  • Track repeat offenders. If a particular domain or email provider consistently returns “catch-all” or “risky” verdicts, investigate it directly. Many ISPs flag known disposable domains — a list hygiene step you can automate.

These filters aren’t just for data crunching. They’re a feedback loop. The more you use them, the faster you’ll spot drifts in deliverability before your open rates drop.

Deliverability isn’t a one-off task. It’s an ongoing discipline.

Use MailTester’s integrations with SendGrid, HubSpot, and Mailchimp to automatically push test results into monday.com. That way, your performance data stays in sync with your marketing workflow — no manual entry, no delays.

Want deeper insight? Run a real-time inbox placement test to see if your messages land in inboxes or get quarantined — even without sending to real users.

Automating the Process with Campaign Tags

Let’s make your deliverability testing stick. Instead of treating each test as a one-off check, tag every campaign with its core purpose: ‘Newsletter’, ‘Promo’, ‘Welcome’, or ‘Re-engagement’. This simple step turns raw data into a living report card for your email strategy.

Tagging Campaigns by Purpose

When you run a deliverability test, assign it a tag that matches its intent. For example, a welcome sequence gets tagged ‘Welcome’. A limited-time offer goes under ‘Promo’. This creates instant traceability across tests you run week after week.

Use tools like MailTester’s inbox placement tester to send real messages through major providers like Gmail, Yahoo, and Outlook. Then, tag each result accordingly. Over time, this builds a reliable record: what types of emails land in the inbox, and which get caught in spam filters.

Filtering and Analyzing by Tag

With tags in place, create a view in monday.com that filters all tests by tag. You’ll see at a glance how ‘Re-engagement’ emails perform across platforms versus ‘Newsletter’ messages. If re-engagement campaigns hit spam filters 70% of the time — as seen in industry trends from Return Path’s annual email deliverability reports — you now have concrete evidence to act on.

Instead of guessing what’s wrong, you can point to data: the subject line, sender domain, or content pattern tied to poor inbox placement. Then, revise the template or tweak sender identity. If your ‘Promo’ emails have strong engagement but low inbox delivery, you may need to adjust alignment with inbox provider standards.

Once you identify a flawed pattern—say, urgency-driven language in re-engagement emails being flagged—stop using that template in future campaigns. Let automation enforce consistency and prevent repetition of known mistakes.

With each tagged test, you’re not just measuring success. You’re building a feedback loop. Let’s use real data to refine content, not guesswork.

Test your email deliverability risk in real inboxes with MailTester’s inbox placement tool, then tag results directly into monday.com for long-term analysis.

How to Interpret Deliverability Changes in Context

Seeing a 3% dip in inbox placement might trigger alarm—until you check the full picture. That drop isn’t a red flag if your spam score also improved. Spam scores reflect how email providers evaluate your reputation. A lower score means your messages are perceived as less likely to be spam, even if inbox delivery dipped slightly. It’s not always about raw numbers; it’s about the balance between reputation and delivery.

Reputation vs. Volume: What’s Really Happening

Let’s say your spam score dropped from 1.8 to 0.9 after a campaign. The inbox placement might have dipped because your sending volume increased slightly, or because providers are applying stricter filtering. This doesn’t mean your emails are failing. It means they’re being scrutinized more closely—but passing inspection. Monitor over time. Reputational health matters more than a single metric.

Now, if you’re seeing a temporary spike in bounces after launching a new campaign, that’s often normal. New sender IPs need time to warm up. Email providers assess new IPs over days, not hours. A few bounces in the first 72 hours are common and shouldn’t be acted on immediately. It’s when bounces persist beyond that window that you should investigate.

Consistently low deliverability on a single domain is a signal worth pausing for. Check SPF and DKIM alignment. Misconfigured authentication is a top cause of rejection. If the domain has a history of abuse—either from past campaigns or shared infrastructure—providers may apply penalties. You can test domain reputations using tools like Spamhaus or MxToolbox, which are standard in the industry.

When deliverability trends don't match your expectations, start with the fundamentals: are your DNS records correct? Is your IP still warming up? Are your messages aligned with best practices for content and frequency? You can test inbox placement across multiple campaigns using MailTester’s inbox placement tester. It shows real-world behavior across inboxes, so you see what users actually see—not just bounce logs.

Don’t react to single data points. Compare trends. Track changes over time. A dip in one metric might be offset by gains in another, like improved spam score or longer message dwell time.

Over time, you’ll learn what’s normal for your domain and IP range. The goal isn’t perfection—it’s consistency and alignment with provider expectations. Tools like MailTester help you audit and refine, not just report.

Real-World Use Case: Tracking a Series of Re-engagement Campaigns

You send seven re-engagement emails over two months. Each campaign uses a different subject line, with slight variations in copy and timing. The goal: bring inactive subscribers back without triggering spam filters. Without structure, this can become a guessing game. But when you track the results in monday.com, every test tells a story. After each send, you run a deliverability test using MailTester’s inbox placement tool. The results — inbox placement rate, spam score, and bounce type — are logged directly into a monday.com workspace. Over time, you build a clear visual of how each subject line affects delivery. The seventh campaign stands out: only 71% of messages reach the inbox. The spam score? 6.2. That’s a red flag.

Diagnosing the Drop

You dig deeper. The sender domain was recently migrated. While SPF and DKIM are set, DMARC is not enforced. That’s a common misstep. As outlined in RFC 7672, DMARC policies help receivers determine whether to accept or reject messages from your domain. Without enforcement, even technically valid emails may be flagged or dropped by providers like Gmail and Yahoo. You suspect the change in domain settings is the root cause. You confirm this by checking the authentication status via MXToolbox or a similar public tool — they show missing or weak DMARC policies. The low inbox placement and elevated spam score align with known patterns of weak authentication.

Testing the Fix

You adjust the DKIM settings and fully enforce DMARC with a policy of `p=reject`. Then, you retest using MailTester’s inbox tester. The new result: spam score drops to 3.8. Inbox placement climbs to 82%. The change is measurable. You’re now reaching 11% more of your target audience. This is how you turn data into action. You don’t guess which subject line works best — you test delivery first. You don’t overlook infrastructure changes — you audit them. monday.com turns each test into a reference point, so you can track progress, compare campaigns, and optimize for real inbox placement. If you're running similar campaigns, you can verify your list before sending through MailTester’s bulk verification or automate checks via the verification API. The same tool that caught the issue can prevent it from happening again. You’re not relying on reputation alone. You’re measuring it. And you’re fixing it — one test at a time.

What This System Can’t Do (And Why That’s OK)

It doesn’t predict future deliverability. It only shows what happened after a test—where emails landed, whether they were blocked, and how sender reputation responded.

It won’t fix poor inbox placement. It shows you the state of your sender reputation, but not the root cause. Addressing issues like spammy content, high complaint rates, or broken authentication is still your responsibility.

What It Does Do

  • Provides real-time visibility into test results across campaigns.
  • Identifies patterns in bounce behavior, spam traps, and delivery failures.
  • Enables comparison of sender performance over time and across segments.

You’re not getting automated fixes. You’re getting data—clear, actionable, and rooted in real delivery outcomes. The decision to optimize content, clean lists, or adjust sending frequency remains with your team.

Keep reading

Ready to put this into practice? MailTester verifies emails with 98.9% accuracy — start with 100 free verifications.

Frequently asked questions

How often should I run deliverability tests?

Run one per campaign before sending. Retest if you change senders, domains, or content significantly.

Can I track deliverability across different email tools?

Yes. MailTester works with any sending platform. Test results can be mapped to campaigns from SendGrid, Klaviyo, or HubSpot.

What’s a good inbox placement rate?

Above 85% is solid. Below 80% signals a need for sender hygiene or domain review.

Does mailTester detect spam traps?

Yes—it checks for known spam traps and warns on high risk or outdated addresses.

How many deliverability tests can I run per month?

No limit—just use your purchased credits. They never expire, so scale freely.

Can I use MailTester without integrating with monday.com?

Yes. You can test lists or campaigns directly in the tool. But linking to monday.com adds comparison and tracking.

What if my deliverability score drops after a clean list?

Check DNS settings (SPF/DKIM/DMARC), sender IP reputation, and content patterns—even clean lists can trigger filters.

How accurate are MailTester's deliverability results?

98.9% accuracy based on real-world validation. It identifies spam traps, invalid domains, and inbox placement with high reliability.

Can I test the same email address multiple times?

Yes. Each test returns independent results. Re-testing can show changes in reputation or inbox rules.

Do I need technical help to set up the API connection?

No. The MailTester API is well-documented. Most users connect via tools like Zapier or monday.com's native integrations.

Is there a free way to try this?

Yes. You get 100 free verifications to start. Use them to test initial deliverability across a few campaigns.

What is a risky email address?

An address with high chances of bouncing or being caught by spam filters but isn't invalid. May indicate a role account, outdated domain, or graylisted sender.