Primary use
DKIM lookup
Resolve the selector record for a domain before and after sender changes.
Free DKIM checker, DKIM lookup, and DKIM test
Run a free DKIM checker to validate email-signing selector records for any domain. Use this DKIM lookup and DKIM test to resolve selector names, inspect the live TXT value, review algorithm and key length, and catch record issues before sender changes break alignment.
Check the live DKIM selector for a domain
Enter the domain and, if known, the selector name. If you leave selector empty, the tool tries common selector hostnames and shows what it checked.
Use this before signing or domain changes
This page is strongest when a team is rotating selectors, onboarding a provider, or trying to understand which DNS record is responsible for current DKIM behavior.
- Validate selector records before enablement
- Check key posture during migrations and rotations
- Reduce guesswork when inherited sender setup is unclear
Pair DKIM lookups with broader auth checks
A healthy selector matters more when it is reviewed together with SPF, DMARC, and real message outcomes instead of in isolation.
- Monitor sender auth as a combined stack
- Review auth drift after provider or DNS changes
- Use message headers as runtime proof
Key details
Signal
Selector health
Confirm the selector name, TXT value, algorithm, and key length look production-ready.
Fallback
Common probes
Search common selector names when the active DKIM selector is unknown.
Next step
Header proof
Use real message headers to confirm the selector you found is the one currently signing mail.
A useful DKIM checker should answer selector and signing questions quickly
The goal is not only to locate a TXT record. It is to show whether the queried selector looks valid, what record name was used, and whether the key posture deserves deeper review.
Selector resolution
Check the intended selector directly or let the tool try common selector names when the active signing path is unclear.
Live TXT value
Inspect the visible DKIM record that receivers use to validate signed messages from the domain.
Key posture
Review algorithm and key-length signals before relying on a selector for production traffic.
Header proof
Pair the DNS lookup with a real Authentication-Results header so you can confirm the selector is signing current mail.
Use DKIM checks as a pre-send or post-change auth checkpoint
Searchers typically need a DKIM checker because a provider changed, a selector rotated, or a message stopped aligning. Treat the lookup as part of change review and incident triage.
Selector rotation
Validate the new selector before switching traffic so the signing path is ready when senders roll forward.
Provider migration
Use the DKIM lookup after cutover to confirm the new provider is using the selector you expect.
Incident review
Pair selector results with header analysis when messages lose alignment or suddenly show dkim=fail.
Use DKIM tests with SPF, DMARC, and inbox placement checks
A valid selector is one part of sender trust. MailSlurp helps teams connect DKIM lookup results to the rest of the path: SPF authorization, DMARC policy, parsed headers, blacklist status, inbox placement, and recurring sender-domain monitoring.
Run the one-shot DKIM check when a selector changes, then confirm real messages show the expected signing domain and selector in Authentication-Results. For launch and migration work, review SPF, DMARC, MX routing, blacklist status, and inbox placement in the same release window.
Related tools
SPF checker
Review SPF alongside DKIM so sender authorization and signing stay aligned.
Open toolDMARC checker
Validate DMARC policy when DKIM alignment is part of a larger auth posture review.
Open toolEmail header analyzer
Inspect real Authentication-Results headers to confirm which selector is currently signing mail.
Open toolDKIM record generator
Create DKIM selector records before validating the published DNS value.
Open toolMX record checker
Review inbound routing when DKIM changes are part of a larger domain migration.
Open toolEmail blacklist checker
Check reputation signals after DKIM, SPF, and DMARC are aligned.
Open toolInbox placement test
Validate whether authenticated messages land where customers can see them.
Open toolDomain monitor
Use domain health checks alongside selector lookups before launch or migration windows.
Open toolFAQ
What does this DKIM checker validate?
This DKIM checker and DKIM lookup tool resolves selector records, shows the queried DNS name, returns the live TXT value when found, and highlights warnings around selector choice, key length, or record validity.
Is a DKIM checker the same as a DKIM test?
For most sender teams, yes. A DKIM checker, DKIM lookup, DKIM check, DKIM test, and DKIM tester all help answer whether a selector record exists in DNS and whether the published key is usable for message signing.
Can I run a DKIM lookup without a selector?
Yes. If you do not provide a selector, the tool checks common selector names and shows the names it tried. That is useful when you inherit a sender domain and do not yet know the active selector.
Why does key length matter in DKIM?
Key length affects signing strength and trust posture. Teams usually want to know whether the selector is using an expected modern key size before relying on it in production.
How should I use the result?
Use the lookup result with SPF and DMARC checks, then confirm real messages show the expected selector and a passing DKIM verdict in Authentication-Results.