Email Deliverability Tester - Check Your Inbox Placement

What This Email Deliverability Test Analyzes

Our email delivery test performs a comprehensive deliverability analysis by sending a test message through our authenticated infrastructure and analyzing how receiving servers respond. Here's what we check:

1. Inbox vs Spam Placement

The primary question: Will your email reach the inbox or be filtered to spam?

Our email deliverability check simulates actual email delivery and analyzes placement signals, including:

• Inbox detection: Whether the message would reach the primary inbox folder
• Spam filtering signals: Indicators that suggest spam folder placement
• Filtering behavior: How aggressively the receiving server filters incoming mail
• Placement prediction: Whether emails are likely to be seen by recipients

Why it matters: An email technically "delivered" to spam is effectively invisible. Our test email tool predicts actual inbox placement, not just technical acceptance.

2. Authentication Status

Modern email delivery requires proper authentication. Our test verifies all three critical protocols:

1. SPF (Sender Policy Framework): Confirms the sending server is authorized to send email for the domain. We test whether our infrastructure passes SPF validation from the recipient server's perspective.
2. DKIM (DomainKeys Identified Mail): Verifies cryptographic signatures that prove emails haven't been tampered with during transmission. Our email delivery checker confirms DKIM signatures are properly validated.
3. DMARC (Domain-based Message Authentication): Combines SPF and DKIM results to provide comprehensive sender authentication. We verify alignment and policy enforcement.

Authentication results show: Pass, Fail, or configuration issues that affect deliverability.

3. Sender Reputation Signals

Email providers evaluate sender reputation when deciding inbox placement. Our test identifies potential reputation issues:

• Domain reputation indicators: How email providers view the sending domain
• IP configuration issues: Problems with sending IP addresses that affect delivery
• Reputation warnings: Signals that suggest deliverability problems
• Trust signals: Whether the sender is established and trusted by email providers

Using our established infrastructure gives you accurate insights into how your emails would be treated by major providers like Gmail, Outlook, and Yahoo.

4. SMTP & Server Response

We analyze how receiving mail servers respond during the delivery process:

• Server acceptance: Whether the receiving server accepts or rejects the connection
• Response codes: SMTP codes that indicate delivery success or failure
• Rejection reasons: Specific reasons if delivery would fail
• Delivery confirmation: Whether the message completes delivery

This reveals issues like blocked senders, server misconfigurations, or delivery restrictions.

5. DNS & MX Configuration

Proper DNS configuration is essential for email delivery. Our email deliverability test validates:

• MX record verification: Confirms mail servers are properly configured
• DNS resolution: Ensures domain names resolve correctly
• Mail server availability: Verifies receiving servers are online and responsive
• Configuration issues: Identifies DNS problems that prevent delivery

Together, these checks provide a complete picture of email deliverability, helping you identify issues before they affect real campaigns.

What Do the Deliverability Results Mean?

After running your email delivery test, you'll receive detailed results showing how your email performed. Here's how to interpret each outcome:

1. Inbox Placement Successful

What it means: Your test email successfully reached the inbox. All authentication checks passed, and the receiving server showed no spam filtering or reputation issues.

Results displayed:

• ✅ Status: CAN RECEIVE MAIL
• ✅ Inbox Placement: WILL REACH INBOX
• ✅ SPF: PASS
• ✅ DKIM: PASS
• ✅ DMARC: PASS

What to do: Your email configuration is working correctly. Emails sent through this infrastructure should reliably reach recipients' inboxes. No immediate action needed.

2. Delivered to Spam

What it means: The email was technically delivered, but would be filtered to the spam folder instead of the inbox. This happens when authentication passes, but other deliverability signals trigger spam filters.

Possible causes:

• Content contains spam trigger words or patterns
• Domain lacks an established sending history
• Recent reputation issues or spam complaints
• Aggressive spam filtering by the recipient's provider
• Missing or weak authentication despite passing basic checks

What to check next:

• Review email content for spam indicators
• Verify that SPF, DKIM, and DMARC are all properly configured with enforcement policies
• Check domain reputation using reputation monitoring tools
• Ensure sending patterns match legitimate email behavior
• Consider warming up new domains or IP addresses gradually

3. Authentication Failure

What it means: One or more authentication protocols (SPF, DKIM, DMARC) failed, significantly reducing deliverability. Email providers are increasingly likely to reject or filter emails that fail authentication.

Results displayed:

⚠️ SPF: FAIL or ❌ DKIM: FAIL or ❌ DMARC: FAIL

Possible causes:

• SPF record missing or doesn't authorize sending servers
• DKIM signature invalid or missing
• DMARC policy not configured or alignment failing
• DNS records not properly published
• Sending from unauthorized servers

What to check next:

• Use our DMARC Checker to verify authentication records
• Confirm SPF includes all authorized sending sources
• Verify DKIM keys are properly configured and signatures generated
• Set up DMARC policy with proper alignment settings
• Test again after fixing the authentication issues

4. Reputation Warning

What it means: The email may be delivered, but it shows reputation signals that could affect future deliverability. This is an early warning that requires attention before problems escalate.

Possible causes:

• Recent increase in bounce rates or spam complaints
• Domain or IP appearing on watchlists
• Sudden changes in sending volume or patterns
• Shared IP reputation issues
• Previous deliverability problems affecting the current reputation

What to check next:

• Monitor bounce rates and complaint rates closely
• Check if the domain or IP is blacklisted using tools like MXToolbox
• Review recent sending patterns for anything unusual
• Ensure email list quality is high and permission-based
• Consider a dedicated IP if currently using shared infrastructure

Server Configuration Issue

What it means: Technical problems with DNS, mail servers, or infrastructure prevent successful delivery. These are configuration issues that must be fixed for emails to work.

Possible causes:

• MX records are missing or pointing to the wrong servers
• DNS resolution failures
• The mail server is offline or not responding
• Firewall blocking mail server connections
• Server configuration errors

What to check next:

• Verify DNS records are properly configured
• Confirm mail servers are online and accessible
• Check firewall rules aren't blocking email traffic
• Use our SMTP Tester to diagnose server connectivity
• Contact the hosting provider if server issues persist

What Is Email Deliverability?

Email deliverability is the ability of emails to successfully reach recipients' inboxes, not just be accepted by mail servers.

An email can be technically "delivered" to a mail server but still fail to reach the inbox. It might land in spam, be silently filtered, or be rejected entirely. True deliverability means emails arrive in the primary inbox where they're actually seen, opened, and engaged with.

Deliverability vs. Delivery:

• Delivery: The email was accepted by the receiving mail server
• Deliverability: The email reached the inbox and is visible to the recipient

Email providers like Gmail, Outlook, and Yahoo evaluate deliverability based on multiple factors:

• Authentication: SPF, DKIM, and DMARC configuration
• Sender reputation: Historical sending behavior and complaint rates
• Engagement: How recipients interact with your emails
• Content quality: Whether the email content appears legitimate
• Infrastructure: Quality of sending IP addresses and domains

Why deliverability matters:

Poor deliverability means your emails may land in spam instead of the inbox, be throttled or silently filtered by email providers, or never reach recipients at all despite appearing to send successfully.

Even well-written, legitimate emails fail if deliverability issues exist. Testing deliverability helps identify problems before they affect real campaigns or critical communications.

Deliverability is not the same as email validation:

Our Free Email Validator checks if email addresses are valid and can receive mail. This email deliverability tester checks whether emails will actually reach inboxes rather than spam folders. Both are important for different reasons.

What Affects Email Deliverability?

Multiple factors determine whether emails reach inboxes. Understanding these helps you maintain strong deliverability:

1. Sender Reputation

Email providers track the reputation of sending domains and IP addresses. Poor reputation leads to spam filtering or blocking.

Reputation factors include:

• Historical bounce rates
• Spam complaint rates
• Sending volume consistency
• Domain age and sending history
• Blacklist status

Maintaining a good reputation requires consistent, legitimate sending behavior over time.

2. Authentication (SPF, DKIM, DMARC)

Modern email requires proper authentication. Email providers increasingly filter or reject emails that fail authentication checks.

SPF verifies sending servers are authorized. DKIM provides cryptographic signatures proving email integrity. DMARC combines both and specifies how to handle authentication failures.

Proper authentication is no longer optional-it's essential for inbox placement.

3. Email List Quality

The quality of your recipient list directly affects deliverability. High bounce rates, spam traps, and inactive addresses damage the sender's reputation.

List quality factors:

• Percentage of invalid or non-existent addresses
• Presence of spam trap addresses
• Engagement rates (opens, clicks)
• Permission-based vs. purchased lists

Regular list cleaning and validation maintain deliverability.

4. Bounce Rates

High bounce rates signal poor list quality and damage reputation. Email providers track how often your emails fail to deliver.

Types of bounces:

• Hard bounces: Permanent failures (invalid addresses)
• Soft bounces: Temporary issues (full inbox, server problems)

Repeatedly sending to addresses that bounce marks you as a low-quality sender.

5. Spam Complaints

When recipients mark emails as spam, it severely impacts deliverability. Even low complaint rates (above 0.1%) cause problems.

Email providers track complaints and reduce inbox placement for senders with high rates. Ensuring recipients want your emails and providing easy unsubscribe options prevents complaints.

6. Engagement Signals

Email providers monitor how recipients interact with your emails. High engagement (opens, clicks, replies) improves deliverability, while low engagement suggests unwanted mail.

Engagement factors:

• Open rates
• Click-through rates
• Reply rates
• Time spent reading
• Moving to folders vs. deleting

Consistently engaging content maintains strong deliverability over time.

Common Email Deliverability Issues

When running an email deliverability check, you may encounter these frequent problems:

1. Emails Landing in Spam

The most common deliverability issue. Caused by weak authentication, poor sender reputation, spam-like content, or low engagement rates. Even legitimate emails can trigger spam filters if not properly configured.

2. High Bounce Rates

Sending to invalid addresses creates hard bounces that damage reputation. Email providers interpret high bounce rates as a sign of poor list management or spam behavior. Keep bounce rates below 2% through regular list validation.

3. Missing SPF Record

Without SPF records, receiving servers can't verify that your sending servers are authorized. This causes authentication failures and increased spam filtering. SPF must list all servers that send email for your domain.

4. DMARC Policy Set to None

A DMARC policy of "none" provides monitoring but no protection or enforcement. Email providers increasingly favor senders with quarantine or rejection policies. Move from monitoring to enforcement after collecting sufficient reports.

5. Shared IP Reputation Problems

When using shared IP addresses, your deliverability depends partly on other senders using the same IP. If they send spam or have poor practices, it affects everyone on that IP. Consider dedicated IPs for high-volume sending.

6. Sudden Drop in Open Rates

A sudden decrease in opens often indicates deliverability problems. Emails may be landing in spam, experiencing increased filtering, or facing reputation issues. Run deliverability tests to identify the cause.

7. Inconsistent Sending Patterns

Large volume spikes or irregular sending patterns trigger spam filters. Email providers expect consistent behavior from legitimate senders. Maintain steady sending volumes and avoid sudden changes.

8. Missing or Weak DKIM Signatures

DKIM provides cryptographic proof of email authenticity. Missing or invalid DKIM signatures increase spam filtering likelihood. Ensure DKIM is properly configured with strong key lengths (2048-bit recommended).

9. Domain Reputation Issues

New domains lack sending history, causing initial deliverability challenges. Recently, problematic domains carry reputation baggage. Warm up new domains gradually and monitor reputation continuously.

10. Blacklist Appearances

If your domain or IP appears on email blacklists, deliverability suffers significantly. Check blacklist status regularly and address issues promptly. Prevention through good practices is better than removal after listing.

Use our email delivery test regularly to catch these issues before they impact campaigns.

Limitations of This Deliverability Tester

Our email deliverability check provides valuable insights into inbox placement and delivery signals. However, like all diagnostic tools, it has certain limitations:

1. Snapshot Test Only

This tool provides instant analysis of the current deliverability status. It doesn't track deliverability over time, monitor ongoing trends, or alert you to gradual changes in inbox placement.

2. Does Not Monitor Over Time

Deliverability can fluctuate based on sending patterns, reputation changes, and recipient behavior. A single test shows the current status but doesn't reveal patterns or track improvements after configuration changes.

3. Does Not Repair Authentication Records

The test identifies authentication failures (SPF, DKIM, DMARC) but doesn't fix them. You'll need to update DNS records and email configuration manually. Use our DMARC Checker to verify authentication setup.

4. Does Not Clean Email Lists

This email delivery test analyzes deliverability for specific test emails. It doesn't validate or clean your entire email list. For address validation and list cleaning, use our Free Email Validator.

Does Not Provide Dedicated Infrastructure

Tests use our shared infrastructure with an established reputation. Results reflect how emails perform using our servers, not necessarily your own sending infrastructure. For testing your specific SMTP setup, use our SMTP Tester.

Cannot Guarantee Future Inbox Placement

Deliverability test results show current conditions. Future inbox placement depends on ongoing sending behavior, reputation maintenance, content quality, and recipient engagement.

No Detailed Content Analysis

The test analyzes technical deliverability factors like authentication and server response. It doesn't provide detailed content analysis for spam triggers, subject line optimization, or email copy review.

Frequently Asked Questions