Free DKIM Checker: Verify Your Email Signing in Seconds
Look up your DKIM record and confirm it is published and formatted correctly, so mailbox providers trust every message you send. Instant results.
Instant Record Lookup
Fetches your published DKIM record straight from DNS so you see exactly what mailbox providers see.
Syntax Errors Flagged
Catches malformed tags, truncated keys, and broken records that quietly fail authentication checks.
Results in Plain English
Each check explains what passed, what failed, and how to fix it, so no DNS expertise is required.
A DKIM checker looks up and validates the DKIM record published for your domain, the cryptographic signature that proves your emails have not been altered in transit. Misconfigured or missing DKIM lets messages fail authentication and slip into spam. This free tool retrieves your record by selector, confirms the public key is present, and flags problems, so you can fix your DKIM setup and keep your email authenticated and trusted.
What the DKIM checker verifies
The checker retrieves the DKIM TXT record at your selector, the specific subdomain where the public key lives, and inspects its contents. It confirms the record exists, parses the version and key type, and checks that the public key is present, complete, and readable by receiving mail servers. It also surfaces common faults such as a missing selector, a truncated key split incorrectly across DNS, or a record that was never published. Because DKIM works alongside SPF and DMARC, the tool gives you a clear view of whether receivers can validate your signature. That confirmation tells you your outgoing mail can be cryptographically verified rather than silently failing authentication.
How to read results and fix DKIM
If the checker finds no record, publish a DKIM TXT record for your selector using the public key your email platform provides, then re-check once DNS updates. If the record exists but the key looks incomplete, it was likely split incorrectly when added to DNS; re-enter it as a single continuous value or use your provider's recommended format. Confirm the selector in your DNS matches the one your sending platform signs with, since a mismatch breaks validation. After changes, send a test message to a mailbox that shows authentication results and confirm DKIM passes. Recheck whenever you switch email providers or rotate keys, so signing never silently breaks.
Why DKIM matters for deliverability
DKIM is one of the three pillars of email authentication, and receivers weigh it heavily when deciding whether to trust a message. A valid signature proves your mail genuinely came from your domain and was not tampered with, which lifts your sender reputation and improves inbox placement. Without working DKIM, your messages are easier to spoof and more likely to be filtered, and DMARC enforcement can reject them outright. Because deliverability depends on receivers being able to verify you, a correctly published DKIM record protects every campaign and transactional email you send. Checking it regularly ensures a DNS change or provider switch never quietly undermines your authentication.
Frequently Asked Questions
What is DKIM and why does it matter?
DKIM is a cryptographic signature that proves an email really came from your domain and was not altered in transit. Mailbox providers like Gmail check it before deciding whether to inbox your mail, so a broken record hurts deliverability.
What do I need to run a DKIM check?
Enter your domain and the selector your email platform uses, such as google or k1. The checker queries DNS for the matching record and validates it. If you are unsure of your selector, your email provider's setup docs list it.
Is the DKIM Checker free to use?
Yes. It is free after creating a Brainito account. Check your record whenever you change email providers or DNS settings, since those are the moments DKIM most often breaks without anyone noticing.
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