https://beacon.optinws.com/ · Developer Tools
3 items
See at a glance whether any website's domain has SPF, DKIM, and DMARC set up correctly for email deliverability. Email Health Checker by Beacon is a free, no-signup tool for checking whether a website's domain has its email authentication set up correctly. Click the toolbar icon on any site and it checks that domain for: SPF — confirms which mail servers are allowed to send email for the domain DKIM — checks for a cryptographic signature that proves mail wasn't altered in transit (checked against common selectors) DMARC — confirms there's a policy in place for handling mail that fails these checks A colored badge on the toolbar icon gives you the at-a-glance result (green = all three found, yellow = partial, red = none found), and the popup shows the detail behind each check. Everything runs directly in your browser using public DNS lookups — there's no account, no sign-up, and no data collected. See our full privacy policy for details. Built by Beacon (optinws.com), a deliverability and inbox-monitoring tool for teams that send email and want to know it's actually arriving.
Sep 7, 2026
rating_count is the Chrome Web Store ratings count, not a written-review count.
Media assets
Screenshots and videos on the listing.
Has promo video
Whether the listing includes at least one video.
Languages
Declared language locales.
Developer website
Listing exposes a developer website URL.
Contact email
Listing exposes a contact email.
Keyword in name
Case-insensitive substring match in the name.
Keyword in description
Case-insensitive substring match in the description.
Keyword occurrences in description
Count of case-insensitive occurrences in the description.
Category user-count percentile
Share of same-category extensions with fewer users (null if unknown).
These are transparent listing completeness / keyword signals, not a prediction of Chrome Web Store search ranking.