openmsg

MBOX viewer

Open a whole mailbox in your browser. Search by sender, subject or date, read each email and save its attachments. Files of several gigabytes work.

Drop your .mbox file here

or select it on your device. Several files at once work too.

The file stays on your device. Nothing is uploaded.

What you see after opening

A Gmail mailbox with 48 emails: list, search and the open email
A Gmail mailbox with 48 emails: list, search and the open email
One .mbox file holds the whole mailbox

What an .mbox file is

An .mbox file holds many emails one after the other in one text file. Gmail Takeout, Thunderbird and Apple Mail use it to export or store mailboxes.

To read it, you normally import it into a mail program. That takes time and mixes old mail with your current mailbox. Here you only look at it.

How to open an .mbox file

  1. Drop the .mbox file on the letter slot above, or select “Select file”.
  2. Wait while the browser reads the mailbox. You see the progress.
  3. Search the list, then select an email to read it.
  4. Save attachments, the single email as .eml, or the list as CSV.

Open a Gmail Takeout export

  1. Unpack the ZIP from Google Takeout.
  2. Open the folder Takeout → Mail.
  3. Drop the file All mail Including Spam and Trash.mbox on the slot above.

Gmail labels are searchable too. Type a label, for example “Inbox” or “Sent”, into the search field.

Open .mbox on Windows and Mac

  • Windows: Windows has no program for .mbox. Thunderbird with the add-on ImportExportTools NG can import the file. On this page you install nothing.
  • Mac: Apple Mail imports .mbox in File → Import Mailboxes. The import mixes old mail with your current mail. On this page you only read it.
  • iPhone and Android: It works in Safari and Chrome. Very large files take longer on a phone.

Nothing leaves your device

Your file
Your browser reads it
You see the email
Our server receives nothing

Frequently asked questions

Is it free?

Yes. You need no account and no sign-up. There is no limit on the number or size of files.

Is my file uploaded?

No. Your browser reads the file on your device. Our server never sees it. You can check this: load the page, switch off the internet, then open the file. It still works.

Where does an .mbox file come from?

Gmail Takeout exports your mail as .mbox. Thunderbird, Apple Mail and many mail servers store mailboxes in this format too.

My Gmail Takeout file is 5 GB. Does it work?

Yes. The browser reads the file in parts of 8 MB and keeps only a list of the emails in memory. On a phone, very large files take longer.

Can I export the list of emails?

Yes. Select “List as CSV”. You get date, sender, recipient and subject of every email for Excel or Google Sheets.

Can I save one email from the mailbox?

Yes. Open the email and select “Save as .eml”. Every mail program opens the .eml file.

How can I open an .mbox file online?

Drop it on the letter slot at the top of this page. The browser reads it on your device, so even large files are not uploaded.

What is the difference between .mbox and .eml?

An .eml file holds one email. An .mbox file holds many emails one after the other. You can save each email from the mailbox as .eml.

What is the best free MBOX viewer?

To keep the emails in a mail program, import the file into Thunderbird or Apple Mail. To only read and search, use this page. You install nothing.