Free Online MBOX Viewer
View the contents of any .mbox email archive with this free tool, no installation needed. Just drag and drop the file into the drop area or click the button to open the file. You can always save and share emails using EmailShot directly next time.
Drag & Drop Mbox File
or
Accepted file format is .mbox
What are MBOX files?
An MBOX file is a standard format for storing multiple email messages in a single plain-text file. The name stands for "mailbox" — it concatenates all emails one after another, each separated by a line starting with From (with a trailing space). Unlike EML files, which store one email per file, a single MBOX file can contain an entire folder's worth of email — from a handful of messages to millions.
MBOX files are used by Mozilla Thunderbird, Apple Mail, Eudora, many Unix mail servers, and Google Takeout. When you export your Gmail archive or move away from Thunderbird, the result is typically one or more .mbox files. With this free MBOX viewer you can inspect every message inside the archive directly in your browser, without any software installation.
How to open MBOX files on Mac
On Mac, Apple Mail can import MBOX files natively: go to File → Import Mailboxes, choose "Files in mbox format," and select your file. Mozilla Thunderbird also works on Mac — use the ImportExportTools NG add-on to import MBOX files into any folder. For instant access without any import step, drop the file into this free online MBOX viewer.
How to open MBOX files on Windows
On Windows, Mozilla Thunderbird is the most common option. Install the ImportExportTools NG add-on, then right-click any folder in Thunderbird and choose ImportExportTools NG → Import mbox file. For a quicker alternative — especially for one-off inspection — drop the MBOX file into this free browser-based viewer without installing anything.
How to export your Gmail as MBOX
Go to Google Takeout, deselect all products, then select Mail. Leave the format as MBOX and download the archive. The resulting All mail Including Spam and Trash.mbox file can be dropped into this viewer or imported into Thunderbird.
MBOX vs EML vs PST — what's the difference?
MBOX stores many emails in one plain-text file — it is a mailbox archive, used by Thunderbird, Apple Mail, and Gmail exports. EML stores a single email per file — it is used for individual message storage and is universally supported. PST is Microsoft Outlook's proprietary binary format that stores emails, contacts, and calendar data together — it requires Outlook or a PST-compatible tool to open.
Frequently Asked Questions
How do I open an MBOX file without Thunderbird?
Drop your .mbox file into the tool above — this free online MBOX viewer parses the archive and lets you browse every message in your browser with no installation required.
How do I open an MBOX file on Windows?
Install Mozilla Thunderbird and the ImportExportTools NG add-on, then right-click a folder and choose Import mbox file. For a faster alternative, use this free online MBOX viewer — no installation needed.
How do I export Gmail as MBOX?
Go to Google Takeout, select Mail, set the format to MBOX, and download. The resulting file can be opened directly in this viewer.
What is the difference between MBOX and EML?
MBOX stores many emails concatenated in a single file (a mailbox archive). EML stores one email per file. MBOX is used for full mailbox exports and archives; EML is used for individual message storage.
Can I extract individual emails from an MBOX file?
Yes — select any email in this viewer and click Download .eml to save it as a standalone EML file. You can then open it with any email client or the EML viewer.
Security and Privacy
We do not store any of the emails you upload to this tool. The mbox file is parsed and displayed in your browser only. If you have any concerns about privacy or security, you can read our privacy policy for more information.