DKIM Test vs Mail-Tester: Which Should You Use?

Mail-Tester is a popular tool for checking email deliverability by analyzing actual sent emails. DKIM (DomainKeys Identified Mail) Test takes a different approach, checking your DNS records directly. Here's when to use each.

Different Approaches

Mail-Tester: Send an email to their test address, get a detailed analysis of that specific message.

DKIM Test: Query your DNS records directly, validate configuration without sending anything.

These aren't competing tools. They solve different problems.

Quick Comparison

What Mail-Tester Does Well

Mail-Tester analyzes your actual sent email end-to-end:

Authentication checks:

• SPF (Sender Policy Framework) pass/fail for your specific message
• DKIM signature validation
• DMARC (Domain-based Message Authentication, Reporting, and Conformance) alignment

Content analysis:

• Spam score (SpamAssassin)
• Blacklist status
• HTML/text quality
• Link checking

Deliverability assessment:

• Overall score out of 10
• Actionable recommendations
• Detailed breakdown

If you want to know "Will this specific email I just sent have deliverability problems?", Mail-Tester is excellent.

Where DKIM Test Excels

DKIM Test focuses specifically on your DKIM configuration:

No email required: You can check DKIM before sending anything. Useful when setting up new domains or services.

Record validation: We parse and validate the actual DNS record, not just whether a signature worked, but whether the record itself is correct.

Selector help: Mail-Tester tells you if DKIM passed or failed. DKIM Test helps you figure out which selector to use in the first place.

Unlimited free usage: Check as many domains and selectors as you need. No daily limits.

Continuous monitoring: Set up ongoing monitoring to catch DKIM changes before they break your email.

When to Use Mail-Tester

Use Mail-Tester when you want to:

• Test a complete email. Check content, headers, authentication all at once.
• Get a spam score. See how likely your email is to be filtered.
• Debug a specific sending issue. Understand why a particular email failed.
• Test before a campaign. Verify everything works before mass sending.
• Check sender reputation. See blacklist status and other reputation signals.

Mail-Tester's strength is holistic email analysis.

When to Use DKIM Test

Use DKIM Test when you want to:

• Validate DKIM configuration. Check the DNS record without sending email.
• Set up a new domain. Verify DKIM before going live.
• Find your selector. Figure out which selector your email service uses.
• Debug DKIM specifically. Isolate DKIM issues from other authentication problems.
• Monitor ongoing. Get alerts when DKIM records change.
• Check multiple domains quickly. Unlimited lookups, instant results.

The Signature vs Record Distinction

This is the key difference:

Mail-Tester checks the DKIM signature. The actual signature in the email header that was generated when you sent the message.

DKIM Test checks the DKIM record. The public key published in DNS that receivers use to verify signatures.

Both need to be correct for DKIM to work:

• The record provides the public key
• The signature proves the email is authentic

If DKIM is failing:

1. Use DKIM Test to verify the record exists and is valid
2. Use Mail-Tester to verify signatures are being generated correctly

Using Both Together

For thorough DKIM troubleshooting:

Pricing Comparison

DKIM Test:

• Free: Unlimited lookups
• Monitoring: Available through Email Deliverability Suite (free tier for 3 domains)

Mail-Tester:

• Free: 3 tests per day
• Paid: From €30/year for unlimited tests

For occasional email testing, Mail-Tester's free tier is fine. For ongoing DKIM monitoring, DKIM Test is more practical.

Bottom Line

These tools complement each other:

• Use DKIM Test to validate and monitor your DKIM configuration
• Use Mail-Tester to test complete emails and get spam scores

Start with DKIM Test to ensure your configuration is correct, then use Mail-Tester to verify everything works end-to-end.