MBOX Viewer – Open an MBOX File Online (Gmail, Thunderbird), No Upload

An .mbox file is a whole mailbox saved as one file — every email, one after another, with its attachments. You get one when you download your Gmail with Google Takeout, export a folder from Apple Mail, or copy a mailbox out of Thunderbird. Open yours below to read it without installing a mail program.

What you can do with it

• Browse by Gmail label. A Google Takeout file keeps your labels — Inbox, Sent, Important and your own — and each becomes a folder here, with how many emails it holds.
• Read any email as it was sent, with sender, recipients and date. Pictures from the internet stay blocked until you allow them; scripts in emails never run.
• Search by sender or subject.
• Save as PDF: one email with its formatting, or tick several emails — or a whole label — and download a ZIP with a PDF of each email and its attachments.
• Keep attachments one by one, or all of an email's attachments as a ZIP. Save any email as .eml to open it in another mail app.

Large files

Gmail exports are often several gigabytes. The page reads the file in pieces on your computer: first it finds where every email starts (you'll see the percentage), then each email is read only when you open it. Nothing is uploaded and the file isn't loaded into memory all at once.

Which files work

• Gmail / Google Takeout: All mail Including Spam and Trash.mbox and per-label files. See how to open a Google Takeout mbox.
• Thunderbird: mailbox files in your profile's Mail or ImapMail folder have no extension (for example Inbox) — choose them anyway; the page recognises them by their content.
• Apple Mail: Mailbox › Export Mailbox creates a folder ending in .mbox. Open that folder and choose the file named mbox inside it.

What it doesn't do

• It doesn't change your file or upload it into another account — it is a viewer.
• Search looks at sender and subject, not the full text of every email.
• Very old or unusual mailbox formats (for example Outlook for Mac's .olm) aren't supported here. For Outlook's .pst use the PST viewer.

FAQ

Is my mailbox uploaded? No. Everything happens in your browser. After the page has loaded it even works offline.

The page says "This does not look like an .mbox mailbox file." The file may still be inside the Takeout .zip or .tgz archive — extract it first. A file that was only partly downloaded can also fail; download it again.

Why do PDFs in the ZIP look plainer than the email? The ZIP keeps each email's header and text so hundreds of PDFs can be made quickly. For a PDF that looks exactly like the email, open it and click Save as PDF.