How it works
DMARC Tester receives or reads one message source and turns it into the same kind of authentication report a receiving mail server would produce.
Use a real mailbox test when you can
The test-address flow is the baseline. You send a normal email from the domain you want to check. The app reads the received message, parses the authentication results, queries live DNS records, and shows the final verdict in one shared result layout.
Use pasted source when you already have a message
The paste flow extracts Authentication-Results, From, Return-Path, DKIM-Signature, and subject data from the source you provide. It then runs the same evaluation and renders the same report shape as the test-address flow.
Preview the report without sending mail
The sample report uses a deterministic fixture. It is there to show the exact layout, wording, response shape, and rule structure that live tests use.