Sendmaster

Check your domain's outbound mail authentication (SPF, DKIM, DMARC) with inline validation and a copy-friendly summary.

Sendmaster is a browser extension that displays SPF, DKIM, and DMARC DNS records for the website you are currently viewing to help you verify your configuration or help to spot potential issues.

Misconfiguration of DNS records can lead to impersonation of your domain or your legitimate outbound email landing in junk folders by default.

What the extension does:
When you click the toolbar icon on a tab, the extension reads the hostname of that tab, derives the root domain, and queries DNS TXT and NS records for it. The results render inside the popup.