Email Content & Link Safety
Paste a full email — headers and body — and SysGlass analyses what receivers and recipients actually see: links whose visible text points one place but go somewhere else, look-alike and punycode sender domains, image-heavy or HTML-only layouts, tracking pixels, and whether the message meets the bulk-sender rules Gmail, Yahoo and Microsoft now enforce (a working one-click List-Unsubscribe). It turns a raw message into a clear deliverability-and-safety report with fixes.
Reviewed by the SysGlass team · Updated July 21, 2026
What it checks
- Phishing signals: link text that doesn't match the link target, bare-IP and shortener links, look-alike/punycode domains
- Sender spoofing: From display name or domain that mimics another brand
- List-Unsubscribe (RFC 2369) and one-click unsubscribe (RFC 8058) for bulk mail
- Content risk: HTML-only with no plain-text part, image-to-text ratio, tracking pixels
- Header hygiene: missing Message-ID or Date, large date skew, Reply-To mismatch
- Per-receiver guidance for Gmail/Yahoo, Microsoft and general inboxes
How to read the result
- OK means the message looks clean: matching links, a one-click unsubscribe where expected, and sane headers.
- Warn flags deliverability or content issues — HTML-only, missing one-click unsubscribe, image-heavy layout, header gaps.
- Fail means a strong phishing signal was found, usually link text that disguises where the link really goes.
- Nothing is sent anywhere — the message is parsed on the server and only the analysis is returned.
Frequently asked questions
What do I paste?
The full raw email, including headers (From, Subject, Content-Type) and the body. In most mail clients use 'Show original' / 'View source' and paste everything.
Does it check SPF/DKIM/DMARC?
Those are covered by the dedicated SPF, DKIM and DMARC tools (which query DNS). This tool focuses on the message itself — links, content, unsubscribe compliance and header hygiene — and gives per-receiver guidance that complements the authentication checks.
Why does one-click unsubscribe matter?
Gmail and Yahoo require bulk senders to support RFC 8058 one-click unsubscribe (a List-Unsubscribe-Post header plus an https unsubscribe URL). Without it, marketing mail is far more likely to be filtered or rejected.
How does it detect phishing links?
It compares each link's visible anchor text to the actual destination's registrable domain and flags mismatches, plus bare-IP links, URL shorteners and punycode look-alike domains — the most common ways a link hides where it really goes.