Email deliverability tools

One-Click Unsubscribe Checker

Paste the headers of a message you sent and see whether your RFC 8058 implementation actually works — including whether your DKIM signature covers the unsubscribe headers, which is the failure that reports nothing and breaks everything.

Email Bounce Decoder

Paste a bounce and get the cause in plain language: hard or soft, whose problem it is, and the fix. It reads the provider-specific error text — gsmtp, S3150, a Microsoft ban range — and shows that provider’s own remedy rather than the generic meaning of the number.

21 guides, one per error code worth its own page.

DKIM Selector Finder

Enter a domain and see which DKIM selectors actually exist for it. Selectors cannot be listed from DNS, so this tests the 273 names every major provider uses, follows the CNAME to whoever really holds the key, and reports key size, testing mode and revoked keys.

The one check every other DKIM tool skips: whether the domain answers for selectors that do not exist.

TLS-RPT Report Analyzer

Drop the .json.gz reports your mail providers send and read them in plain English. Parsed entirely in your browser — the file never leaves your device, which is the part other tools charge for.

All 11 RFC 8460 result types explained, one guide each.