MSG & EML Email Viewer: Open Email Files Online

.eml. The file is parsed according to RFC 5322 and MIME with the postal-mime library: address headers, encoded words in subjects, multipart bodies, plain-text and HTML alternatives, inline images (referenced by cid:) and attachments, including a forwarded message attached as .eml.

.msg. An Outlook message is a compound file (the Microsoft MSG / CFB structure). The viewer reads it with the msgreader library: subject, sender (an internal Exchange address is replaced by the internet address from the headers where possible), recipients with their To, Cc and Bcc types, transport headers, body text, HTML body, and attachments. When a message stores its HTML only inside the compressed RTF copy (a common Outlook behaviour), the RTF is decompressed and the original HTML is rebuilt from the encapsulated tags, so the formatting survives. Plain RTF becomes text.

Safe display. HTML is parsed into an inert document and cut down to an allow-list of tags and attributes: scripts, forms, frames, objects, SVG, meta refresh, base and link elements and every event handler are removed, javascript: and data: links are dropped, inline CSS has its url() references, @import and expression() removed, and positioning that could cover the page is neutralised. Remote images and fonts are blocked (they would tell the sender that you opened the mail), while images embedded in the message are shown. The result goes into an iframe without script permission and with a Content-Security-Policy of default-src none and images from data only. Links open in a new tab only when you click them.

Notes and attachments. The viewer points out a Reply-To address on a different domain than the sender, a differing Return-Path, and shows an Authentication-Results header as text the receiving server wrote (it is not verified). Attachments are listed with name, type and size and saved as plain files with a button; executables, scripts, HTML and macro files are marked. They are never opened or run in the page.

.msg (Outlook, compound file) and .eml (RFC 5322) files up to 80 MB. Not unpacked: encrypted or S/MIME-signed content, TNEF attachments (winmail.dat), embedded .msg attachments (listed, not opened) and calendar items shown as messages. Legacy .oft templates and .pst mailboxes are not supported.

1. Drop a .msg or .eml file onto the box (up to 80 MB).
2. Read the header block and any notes, then the body in HTML or plain-text view.
3. Save an attachment with its Save button if you need it, after checking its type.
4. Use "Print or save as PDF" for a copy of the message, and open "All headers" for the technical details.

• Reading an Outlook message on a Mac, Linux or phone without Outlook
• Looking at a suspicious email file without opening it in a mail program
• Extracting an attachment from a .msg file
• Saving an email as PDF for a case file
• Checking the headers of a message that was saved from a mail server

HTML mail is reduced to a safe subset, so some formatting is lost, and a message that depends on remote images or styles can look different from how it looked in a mail program. The tool shows what is in the file; it does not check whether the sender is who the message claims, whether attachments are harmless, or whether links lead to safe pages. The authentication header is displayed as text and is not verified.

Some .msg files use features the reader does not decode (for example certain compressed or encrypted bodies); the viewer then shows what it can and says what is missing. Attachments are saved as they are: do not open an executable, script, HTML or macro file unless you trust its source, even if it came from someone you know.