Email diagnostics
Email header analyzer
Paste raw email source to inspect SPF, DKIM, and DMARC authentication results, trace hop-by-hop delivery delays, and spot mismatched sender headers.
What the headers tell you
Incoming emails include a block of headers above the message body where mail servers record authentication checks and routing timestamps. Mail clients hide these fields by default, so inspecting the raw headers is the fastest way to diagnose why a message landed in spam, arrived hours late, or failed sender verification.
Pasting the raw message source breaks that log into three views: whether the message passed sender authentication, where it spent time in transit, and how individual header fields were set.
Authentication
Shows the SPF, DKIM, and DMARC verdicts recorded by the receiving mailbox so you can confirm whether the sender domain passed verification.
Delivery path
Lists the mail relays that handled the message in chronological order alongside the elapsed time at each hop to pinpoint transit delays.
Header breakdown
Unfolds headers such as From, Return-Path, and Message-ID into a searchable table so you can compare the visible sender against the return address.
Analyze a message
Copy the original message source from your mail client and paste it below. Header parsing runs locally in your browser without uploading message content.
Your message
Paste the raw email or its headers
Put it into practice.
Continue with the documentation, guides and examples for this topic.