Web & SEO Tools

How to Use the SPF, DKIM & DMARC Checker

2026-11-135 min readBy Apex Tool Station Team

Check a domain’s MX, SPF, DKIM and DMARC records, with clear warnings that help your emails reach the inbox instead of spam.

100% free No signup Works in your browser

Open the SPF, DKIM & DMARC Checker tool

1. What is the SPF, DKIM & DMARC Checker?

Gmail, Outlook and Yahoo now expect senders to prove their emails are genuine. Three DNS records do that job: SPF lists the servers allowed to send for your domain, DKIM adds a digital signature to each message, and DMARC tells receivers what to do when a message fails those checks. If any of them is missing or wrong, your invoices and newsletters can land in spam.

This checker reads all three plus your MX records, counts SPF DNS lookups against the limit of 10, tries more than 20 common DKIM selectors (Google, Microsoft 365, Zoho, SendGrid and others), and explains each problem in plain words with an example fix.

Check a domain’s MX, SPF, DKIM and DMARC records, with clear warnings that help your emails reach the inbox instead of spam. It offers runs on our own server, no sign-up, private and reserved addresses are blocked and results are not stored.

2. How to use the SPF, DKIM & DMARC Checker

Here is the whole process, step by step. It takes less than a minute from opening the tool to seeing your result.

1Enter your domain (or any email address at it).
2Optionally type your DKIM selector if you know it.
3Press Check to read MX, SPF, DKIM and DMARC records.
4Fix the red and orange items to improve inbox delivery.

Press the "Check" button and your result appears on the page.

Everything runs in your browser — your files and text never leave your device.

3. What you can do with it

Runs on our own server, no sign-up
Private and reserved addresses are blocked
Results are not stored
Run the tool with the "Check" button when your input is ready.
Run a live check — the server makes the request and sends the result back to your browser.

4. Tips for best results

Nothing you check is stored — The server makes the request, sends the result back to your browser and keeps nothing. Private and internal network addresses are blocked for safety.
It works on your phone too — Open the tool in any modern browser on Android or iPhone. The layout adjusts to the screen and everything works the same way on a small screen as on a desktop.

5. Key features

Runs on our own server, no sign-up

Private and reserved addresses are blocked

Results are not stored

Frequently asked questions

What is a DKIM selector?

It is the name that points to your public key, such as “google” or “selector1”. Open any email you sent, view the original message and look for s= in the DKIM-Signature header.

Should I set DMARC to reject straight away?

Start with p=none and a rua address to receive reports. After a few weeks of clean reports, move to quarantine and then reject.

Is the SPF, DKIM & DMARC Checker free?

Yes. The SPF, DKIM & DMARC Checker on Apex Tool Station is 100% free with no signup and no watermark. Browser tools have no usage limits.

Do you store the websites or domains I check?

No. Our server makes the request, sends the result back to your browser and keeps nothing. Private and internal network addresses are blocked for safety.

Does it work on mobile?

Yes. The tool works on any modern browser on Android, iPhone, Windows, Mac and Linux.

Apex Tool Station TeamFree Online Tools

The team behind Apex Tool Station. We build free online tools that run in your browser — no signup, no uploads, no watermarks.