Folders and labels
All messages
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Select a message from the list to read it here.
Univik Online MBOX Viewer
100% private. Runs only on your device
Thunderbird, Apple Mail and Gmail Takeout mailboxes. Any device, nothing to install, nothing uploaded.
Or pick it from your device. Messages open in this tab, on your own computer, phone or tablet. Your mailbox is never uploaded.
Most online MBOX viewers upload your file to a server and send the messages back. This one is a single web page: when you pick a .mbox file, your browser reads it from your disk in small pieces and builds the message list itself.
No upload, no account and no server. Open the page, go offline and it still works. Safe for private mail, client mailboxes and email evidence.
Windows, Mac, Linux and Chromebook. Any modern browser such as Chrome, Edge, Firefox or Safari opens an MBOX file here.
Download a message as .eml, save any attachment, pull all attachments of a message as a zip and export the message list as a spreadsheet.
Short answer: this tool opens .mbox files on Windows, Mac, Linux, Chromebook, iPhone, iPad and Android in any modern browser. No Thunderbird, Apple Mail or Gmail account needed and nothing is uploaded.
Safari or Chrome opens any .mbox here, and Select a folder handles an Apple Mail export package. The Apple Mail viewer page covers the package and the emlx question.
Save the file to the Files app, open this tool in Safari and tap Choose. Sizes, sharing and the App Store question are on the iPhone and iPad viewer page.
iPadOS Safari shows labels, list and reader side by side, the same layout as a laptop. Details sit with the iPhone and iPad page.
Chrome, Samsung Internet or Firefox picks the file from Downloads or Drive and builds the list on the phone. See the Android viewer page.
ChromeOS has no mail app that reads MBOX, so this tool fills the gap from Files or Drive. More on the Chromebook viewer page.
Firefox or Chromium on any distribution. Evolution, KMail, Claws, mutt and spool files are covered on the Linux mailbox page.
Edge or Chrome for a quick look with nothing installed. For body search, printing or a whole profile at once, install the free Univik MBOX Viewer for Windows.
The viewer reads the MBOX format directly, message by message, the same way a mail client does.
mboxo, mboxrd, mboxcl and mboxcl2, whether the file escapes From lines or marks each message with a Content-Length. Thunderbird, Gmail Takeout, Apple Mail, Eudora, Postbox, SeaMonkey, Evolution and Dovecot mail spools all open.
Windows CRLF, Unix LF and classic Mac CR line endings are all handled, so a mailbox copied between systems still opens with the right message count.
X-Gmail-Labels values, including labels in Hindi, Arabic, Chinese or any other script, nested labels such as Work/Clients and labels that contain commas. Thread IDs are kept for export.
Rich HTML messages with embedded (cid:) pictures shown in place. Remote tracking images stay blocked until you choose to load them.
PDF, Office, image and zip attachments with names in any language, plus forwarded messages attached as .eml. Preview pictures and download any file.
Raw headers for Message-ID, Received and DKIM checks. Base64, quoted-printable, UTF-8, ISO-8859, Windows-125x, Shift_JIS, GBK and EUC-KR. Subjects in Chinese, Japanese, Korean, Arabic or Hindi read correctly.
A half-downloaded file, two mailboxes joined into one or junk between messages still opens. The viewer finds the next real message and keeps reading.
Drag a .mbox file onto the box at the top or click Choose .mbox files. Thunderbird files without an extension and Apple Mail .mbox folders work too.
The message list fills up while the file is read. Filter by label, search by sender or subject and click a message to read it.
Save a message as .eml, download an attachment, zip all attachments of a message or export the list as .csv.
Each mail program stores or exports MBOX a little differently. The online viewer understands all of these.
Takeout writes All mail Including Spam and Trash.mbox, split into parts for big accounts. Labels, file names and settings are on the Gmail Takeout viewer page. Workspace admins exporting a matter want the Google Vault viewer page, and a group archive the Google Groups viewer page.
Mailboxes sit in the profile with no extension: Inbox, Sent, Archives. Pick the file, not the .msf index. Paths, ImapMail and compacting are on the Thunderbird mail viewer page. SeaMonkey and Postbox use the same layout and have their own SeaMonkey and Postbox viewer pages.
Mailbox → Export Mailbox writes a package such as Inbox.mbox with the mailbox inside. Use Select a folder and pick it. Package internals, Windows handling and the emlx question are on the Apple Mail export viewer page.
Evolution, KMail, Claws Mail, mutt, Alpine and the /var/mail spool all write mbox. Paths and export steps for each are on the Linux mailbox viewer page.
Mail from a dead program still opens here: Eudora .mbx, Opera Mail .mbs and Entourage .mbox exports each have a page.
Bridge writes one .mbox per folder, the Export Tool writes .eml. Both open via the Proton Mail viewer page.
Univik makes both. Use this online page for a quick look on any computer or phone. Use the free Univik MBOX Viewer for Windows when you need body search, printing or whole profile folders.
| Feature | Online MBOX Viewer | MBOX Viewer for Windows |
|---|---|---|
| Install needed | None, opens in the browser | 15 MB Windows setup |
| Operating system | Windows, Mac, Linux, Chromebook, iOS, Android | Windows 7 to 11 |
| Files uploaded | Never, runs on your device | Never, runs on your PC |
| MBOX variants | mboxo, mboxrd, mboxcl, mboxcl2 | mboxo, mboxrd, mboxcl, mboxcl2 |
| Gmail Takeout labels | Label filter | Shown per message |
| Large files | Read in pieces, multi GB files open | No size limit |
| Search | Sender, subject, recipients, labels | Message bodies too |
| Thunderbird profile folders | One folder at a time | Whole profile with subfolders |
| Browser print of the open message | Direct printing | |
| Price | Free | Free |
Direct answers about opening Thunderbird, Apple Mail and Gmail Takeout mailboxes in a browser, on any device, without a mail program.
No. This page contains the whole viewer. Your browser reads the file from your device in small pieces and builds the message list itself. There is no server involved and the page keeps working with the internet switched off. Remote pictures inside HTML mail are blocked until you click Show remote images.
Open this page in any browser, drop the .mbox file into the box at the top and the message list appears. You do not need Thunderbird, Apple Mail, Outlook or any download. Click a message to read it, use the tabs for the plain text, raw headers and attachments.
Yes. Univik Online MBOX Viewer is free, has no message limit and needs no sign up. Downloading messages as .eml, saving attachments and exporting the list as .csv are free as well.
Open this tool in Safari or Chrome on macOS and choose the file, or use Select a folder for an Apple Mail export. No import into Mail is needed. Details are on the Apple Mail viewer page.
Save the .mbox to the Files app, open this page in Safari and tap Choose .mbox files. Keep phone exports to a few gigabytes. The iPhone and iPad viewer page has the full walk through.
Pick the file named Inbox, Sent or Drafts itself, not the small .msf index beside it. Subfolders live in folders ending in .sbd. Where the profile is on Windows, Mac and Linux is covered on the Thunderbird viewer page.
Some viewers split only on a Unix line break, so a Windows file with CRLF endings or an old Mac file with CR endings shows as one huge message. This tool works out the line ending before anything else, then splits on the genuine "From " lines, so the count matches your mail program. The Mailbox summary on the left names the line ending in use.
Often, yes. If a download stopped early, every message before the cut is fine and the last one shows up to where the file ends. If two mailboxes were joined or there is junk between messages, the viewer finds the next real "From " line and carries on. The one file it turns away is a mailbox saved as UTF-16, and it asks you to save it as UTF-8 and try again.
It is as safe as your own computer, because the file never leaves it. The tool opens the file read only and never writes to it. Raw headers, Message-ID and Received lines are shown unchanged so you can check them. For formal casework with reports, hashing and bulk export, use a desktop tool such as the Univik MBOX Viewer for Windows.
No. The page is the app. There is no browser extension, no plugin and no setup. Bookmark it and come back whenever you need it.
Free, private and nothing to install. Your mailbox stays on your device.
Choose an .mbox file