DKIM Test vs MXToolbox: Which DKIM Checker Should You Use?
Compare DKIM Test and MXToolbox for checking DKIM records. See the differences in features, ease of use, and when to use each tool.
Last updated: 2026-01-28
If you've searched for a DKIM checker, you've probably come across MXToolbox. It's one of the most well-known DNS and email testing tools. But is it the best option for checking DKIM records? Here's how DKIM Test compares.
Quick Comparison
| Feature | DKIM Test | MXToolbox |
|---|---|---|
| DKIM lookup | Yes | Yes |
| Selector input | Prominent field | Separate field |
| Selector guide | Yes (16 providers) | No |
| Key validation | Yes | Basic |
| Record parsing | Detailed breakdown | Raw + parsed |
| Continuous monitoring | Yes (via Suite) | Yes (paid) |
| Free tier | Unlimited lookups | Limited daily |
| Focus | Email deliverability | General DNS/email |
What MXToolbox Does Well
MXToolbox is a comprehensive toolkit. Beyond DKIM, it offers:
- MX record lookups
- Blacklist checking
- SMTP diagnostics
- DNS propagation testing
- SPF and DMARC checking
If you need a Swiss Army knife for DNS and email troubleshooting, MXToolbox covers a lot of ground.
Where DKIM Test Excels
DKIM Test is purpose-built for DKIM validation:
Selector-first design. The selector field is prominent, not hidden. Since DKIM lookups require a selector, this matters. We also provide a detailed selector guide covering 16+ email providers to help you find the right one.
Better error messages. When something's wrong, we explain what it means and how to fix it—not just "record not found."
Faster results. No navigating through multiple tools. Enter domain, enter selector, get results.
Integrated monitoring. Check once, then set up continuous monitoring through the Email Deliverability Suite to catch changes before they break your email.
The Selector Problem
Here's where many DKIM tools fall short: you need to know your selector to look up a DKIM record.
MXToolbox requires you to know and enter the correct selector. If you don't know it, you're stuck guessing or digging through documentation.
DKIM Test helps by:
- Providing a selector guide with instructions for every major email provider
- Showing a dedicated selector input field alongside the domain field
- Linking to selector help when lookups fail
Don't know your selector?
Check our guide on finding your DKIM selector for step-by-step instructions for every major email provider.
When to Use MXToolbox
MXToolbox makes sense when you:
- Need to check multiple DNS record types at once
- Want SMTP connection testing
- Need blacklist monitoring across many lists
- Prefer an all-in-one dashboard
When to Use DKIM Test
DKIM Test is better when you:
- Just need to validate a DKIM record quickly
- Don't know your selector and need help finding it
- Want clear explanations of DKIM issues
- Need ongoing DKIM monitoring alongside SPF, DMARC, and MX
Monitoring Comparison
Both tools offer monitoring, but with different approaches:
MXToolbox monitors as part of a broader DNS monitoring package. DKIM is one of many record types they track.
DKIM Test (via the Email Deliverability Suite) focuses specifically on email authentication—SPF, DKIM, DMARC, and MX records. You get alerts when any of these change or break, with context about what went wrong and how to fix it.
Monitor all your email records
SPF, DKIM, DMARC, and MX monitoring in one dashboard. Get alerts before deliverability breaks.
Pricing
DKIM Test: Free unlimited lookups. Monitoring available through the Email Deliverability Suite (free tier for up to 3 domains).
MXToolbox: Limited free lookups per day. Paid monitoring plans available (check mxtoolbox.com for current pricing).
Bottom Line
MXToolbox is a solid general-purpose tool. If you need broad DNS diagnostics, it's useful.
But for DKIM specifically? DKIM Test is more focused, handles the selector problem better, and integrates with purpose-built email deliverability monitoring.
Use the right tool for the job.