Primary use
DKIM lookup
Resolve the selector record for a domain before and after sender changes.
Free DKIM checker
Free DKIM checker and DKIM lookup tool
Run a free DKIM checker to validate email-signing selector records for any domain. Use this DKIM lookup tool to resolve the selector name, inspect the live TXT value, review algorithm and key length, and catch record issues before sender changes break alignment.
Run a free DKIM lookup
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 case
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
Upgrade path
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.
What this checks
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
Name resolution
Check the intended selector directly or let the tool try common selector names when you are not sure.
Record
Live TXT
Inspect the visible DKIM TXT value that receivers will use to validate signatures.
Key
Length and algorithm
Review the cryptographic posture that the selector appears to expose in DNS.
Coverage
Checked names
See which selector hostnames were probed during lookup when the active one is unclear.
Operational use
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.
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 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.
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.