WINDOWS
A double-click away.
For Windows 10 or later on Intel/AMD 64-bit computers.
Download for WindowsZIP · 16.4 MiB · Includes Python
- Extract the entire ZIP.
- Double-click Start Postbox.bat.
- Your browser opens the local viewer.
LOCAL. OFFLINE. YOURS.
Your archive.
Close at hand.
Give your exported email a home. Read messages, find the file you need, and bring a little order to your archive.
Get PostboxFree to use · Windows & Linux · Python included
TAKE YOUR INBOX WITH YOU
Download. Extract. Open.
No installer, no account, and no Python setup. Keep the extracted folder together on your computer or USB drive.
LINUX
Ready for your desktop.
For Intel/AMD 64-bit Linux with glibc 2.17 or later.
Download for LinuxTAR.GZ · 87.7 MiB · Includes Python
- Extract the entire archive.
- Open a terminal in the extracted folder.
- Run
./"Start Postbox.sh".
If the launcher needs permission
chmod +x "Start Postbox.sh"
./"Start Postbox.sh"Run from a folder that permits executable files. ARM and Alpine/musl systems need a different runtime.
Download the source ZIPSHA-256 checksumsBrowse the code on GitHub ↗
Read the blog post: Postbox—a free way to read your Proton Mail and MBOX exports ↗
The download page is online. The viewer runs on your own computer at a localhost address and works without internet after download.
LESS HUNTING. MORE FINDING.
An email archive you can actually use.
Open your exports.
Import EML and Outlook MSG messages, MBOX archives, and Outlook PST mail folders. HTML opens automatically when available, with a plain-text fallback and a green Next button.
Search with purpose.
Combine from:, to:, cc:, subject:, body:, and has:attachment. Search includes HTML-only message text and attachment filenames.
See what came with it.
Preview PDFs, photos, audio, and video. Read extracted text from DOCX and supported DOC files. Download the original attachment whenever you need it.
Make room for what matters.
Browse year/month groups, select a date range, and export attachments into folders. Select multiple messages or attachments for deletion, then advance to the next email.
YOUR FIRST FIVE MINUTES
Keep it local.
Keep it simple.
Once the viewer opens, choose Open managed folder to work with original email files, or import copies to browse.
- Choose your archive. Open
.eml,.msg,.mbox,.mbx, or.pstexports. Files stay on your computer. - Find a message. Try
from:ada has:attachment, or filter by dates and select the matching results. - Save what you need. Export attachments to a chosen folder, organized by year, month, and email.
- Close when you’re finished. Keep the launcher’s terminal open while using Postbox. Press Ctrl + C there to stop it.
A few useful details.
Which browser should I use?
Chrome or Edge supports choosing folders and changing original files. Other modern browsers can read imported copies, delete from the session, and export attachments as a ZIP. PDF and media previews depend on your browser and codecs.
What does Delete this email do?
It follows the selected deletion mode. Original-file deletion removes an EML file or rewrites its MBOX archive; embedded attachments go with the email. Attachment-only deletion rewrites the source email. Session-only deletion leaves files on disk unchanged. Confirmation and original-file checks happen first; separately exported files are never removed. Successful deletion opens the next remaining message. Deletion cannot be undone in Postbox.
Does it upload my email or load trackers?
The app uses a loopback server on your computer. It has no external email service, analytics, or account. Message HTML is sanitized and isolated; scripts, remote images, and navigation are blocked. MBOX and PST parsing briefly use a local temporary file, which is removed after parsing.
What are the limits?
PST imports are limited to 2 GB and are streamed through a temporary local file. Other imports are limited to 100 MB. Extracted messages and attachments are held in memory, so large mailboxes need sufficient RAM. PST originals stay read-only; export selected emails as EML ZIP or MBOX, or delete only from the session. MSG files can be deleted as whole originals, but attachment edits require a session copy or EML export. Contacts and calendar records are not imported. Word previews show text rather than page layout; encrypted and unsupported document variants require another application. Attached-file contents are not indexed by email search.
Has it been tested on both operating systems?
The bundled Linux runtime, MIME/MBOX/Outlook handling, and organizer have automated checks. PST and MSG imports were also checked against public sample exports, including attachment extraction. Navigation and file actions have DOM regression tests with simulated file handles. Packaged-runtime checks run on Windows and Linux in GitHub Actions; native file-picker interactions are tested with simulated handles.