Tools
Free email tools.
No signup, no tracking, no rate limit. Built by the SNDR team because every team eventually needs them.
DKIM record checker
Lookup + parse + validate any domain's DKIM record. Follow CNAME indirection (M365, SendGrid), estimate key size, distinguish revoked from broken, auto-try common selectors.
OpenSPF record checker
Parse the mechanisms, count the DNS lookups against the spec's 10-lookup ceiling, and check the all-qualifier so you know if spoofing is actually blocked.
OpenDMARC record checker
Resolve the DMARC policy, parse every tag, and tell you whether the record monitors (p=none) or enforces (quarantine / reject).
OpenMX record lookup
Resolve every MX record for a domain, sort by priority, and resolve each MX hostname to its A records so you see the full delivery path.
OpenIP blacklist (DNSBL) checker
Check an IP against the major DNSBLs in parallel. Distinguishes real listings from Spamhaus-style "public-resolver-refused" responses so you never get false positives.
OpenEmail header analyzer
Paste raw email headers — parse the SPF/DKIM/DMARC verdicts, the envelope fields, and the full hop trace. Runs entirely in your browser, no data uploaded.
OpenStart building
Your next message starts here.
Connect your domain, create an API key, and send with SNDR.