DomainCanary

Use this when someone lists the services that send their email and wants the SPF record to publish, or wants a sender added to the SPF record they already have. Takes provider names such as Google Workspace or Mailchimp, include terms such as include:spf.example.com, or IP addresses, and returns one merged record with its count of DNS lookups against the limit of ten. Pass the domain when you know it, so the result includes the senders already in its published record.

build_spf

Use this when someone asks whether a domain's email authentication is set up correctly, why mail from a domain fails DMARC, SPF or DKIM, or which DNS records to publish for it. Reads the domain's live DMARC, SPF and DKIM records and returns what is wrong with each, plus the records to add or change. Pass a DKIM selector when you know it. Without one, common selectors are tried. Takes a domain name only, not a mailbox address or an IP address.

check_domain

Use this when someone pastes a bounce message, an SMTP reply such as 550 5.7.26, or an Authentication-Results header and asks what it means or how to fix it. Returns what the receiving server refused, what to change, when it clears, and the page that explains it. Works from the pasted text alone and reads no DNS records.

explain_bounce

Use this when someone has a DMARC aggregate report and wants to know which senders passed and which failed. The report is the XML, .gz or .zip file that receivers such as Google and Yahoo email to the address in a domain's rua tag. In ChatGPT, pass the uploaded file. Elsewhere, pass the report XML as text. Returns totals per report and each sending IP address with its SPF, DKIM and DMARC results. The result gives a next step for the report's domain and a link to a live check of that domain's DNS records. Nothing from the report is stored.

analyze_report