Introducing SendSignal Tools
Every email team ends up with the same browser bookmarks: a DNS lookup here, an SPF checker there, a header analyzer somewhere else. We got tired of bouncing between them, so we built SendSignal Tools: one fast, free toolbox for the checks email people run every day.
What's in it #
- DNS lookups: A, AAAA, PTR, MX, TXT, NS, CAA and SOA records, with TTLs.
- SPF checker and minimizer: expands every include, counts DNS lookups against the 10-lookup limit, and can flatten an over-limit record into a zero-lookup version.
- DKIM, DMARC and BIMI checkers: fetch a record or paste one, and every tag gets a plain-English explanation instead of a pass/fail black box.
- Blocklist check: your sending IP against the major DNSBLs in parallel, with each list's return codes decoded.
- Header analyzer: paste raw headers to see the delivery path hop by hop, where the delays were, and how the message authenticated.
- Encoding helpers: decode Base64, Quoted-Printable and
=?utf-8?...?=subject lines, and search Unicode glyphs by name.
Built to be shared #
Every check that reads from DNS lives at a shareable URL: run a check, copy the address bar, and paste it in a ticket or a Slack thread. Paste-based tools (validators, the decoder, the header analyzer) run in memory and are never stored or logged.
Why we built it #
We build SendSignal, an email platform for developers. Deliverability work is our day job, and these are the tools we wanted to exist. If a check surfaces something confusing about your SPF tree or your DMARC policy, that's exactly the kind of thing our platform handles for you.