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Open a MBOX email online, free

Open .MBOX email files online. Read messages, headers and attachments, free MBOX viewer.

Drop your .MBOX file here

Opens your .MBOX file right here.

Choose .MBOX file
Up to 500 MB · mailboxes with thousands of messages are fine
Instant. Opens in seconds
Safe view. No scripts, no tracking
100% free. No Outlook needed

How to open a .MBOX file online

No mail account and no extra software to install.

01

Pick your .MBOX file

Drag it in or click to choose it. It opens here in a moment.

02

Read it safely

The message opens in a locked-down view: scripts never run, and remote images often used for tracking stay blocked until you allow them.

03

Check and save

Download attachments, read the full headers, and see every server the message passed through, with SPF, DKIM and DMARC results.

About .MBOX files

What a .MBOX file is, and what's inside it.

An MBOX file is a mailbox, a single plain-text file that holds many email messages stored one after another. Google Takeout exports Gmail as .mbox, and Thunderbird and Apple Mail use the format too. The standard way to open it is to import it into Mozilla Thunderbird (free) with the ImportExportTools NG add-on. To move the mail into Outlook you need to convert MBOX to PST, since Outlook cannot read mbox directly.

Programs that open .MBOX files

Windows
Any text editor (Notepad++ etc.), Mozilla Thunderbird + ImportExportTools NG
macOS
Apple Mail, Mozilla Thunderbird + ImportExportTools NG
Linux
Mozilla Thunderbird, Evolution / KMail, mutt / command-line tools
.MBOX format details
Full nameMbox Mailbox (email container)
DeveloperOriginated in Unix mail systems (Fifth Edition Unix, 1970s); no single owner
First released1970s (Unix mail); informally documented as RFC 4155 (2005)
CategoryEmail
MIME typeapplication/mbox

Related viewers

Open the attachments you find.

Is it safe to open a suspicious .MBOX file here?

Safer than in a mail client: the message runs in an isolated frame with scripts disabled, remote images and trackers are blocked until you allow them, and attachments are never opened automatically.

How can I tell if an e-mail is fake?

Look at the Message info panel. We show the SPF, DKIM and DMARC results recorded by the receiving server, warn you when the Reply-To address differs from the sender, and list every server the message passed through.

Can I open a Gmail or Thunderbird mailbox (.mbox)?

Yes. Drop the .mbox file and you'll get a searchable list of every message. Click one to read it.

Why does my MSG file show plain text only?

Some Outlook messages store their formatting only as compressed RTF. We show the text today; full RTF formatting is coming soon.

Can I open .pst or .ost files?

Not yet. Outlook data files are on our roadmap. Meanwhile you can export single messages from Outlook as .msg and open them here.

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