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 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 pass/fail for your specific message
• DKIM signature validation
• DMARC 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.