Build SPF (v=spf1) and DMARC (v=DMARC1) TXT records to stop email spoofing.
Execution runs 100% locally inside the browser sandbox using HTML5 Canvas, Web Cryptography Subtle API, and Web Workers. Zero egress.
Zero network latency. Operates completely offline with zero dependencies on third-party backend servers or cloud services.
Built according to official RFC specifications, cryptographic test vectors, and enterprise-grade data transformation standards.
Type your root domain name.
Toggle Google Workspace or Microsoft 365 SPF includes.
Copy SPF and DMARC TXT records into your DNS zone.
p=reject instructs receiving mail servers to outright block spoofed emails claiming to be from your domain.
-all is a hard fail (reject unlisted senders), while ~all is a soft fail (mark as spam).
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