MBOX explained

An MBOX is many internet messages in one long file.

Messages are separated by From_ lines and contain normal email headers and MIME bodies. Real archives vary, so tolerant incremental parsing matters.

Workspace status

Ready · Local browser memory

Open an email file

Open it once. Reader, safety, headers, route, redaction, and export reuse the same in-memory source.

.EML
.MSG
.EMLX
winmail.dat
Processed locally. Files and filenames stay on this device.
Workflow

From source file to finished result

Runs locally
  1. Step 1

    Drop the archive

  2. Step 2

    Index message boundaries progressively

  3. Step 3

    Search and open individual messages

What this workspace preserves

Common in Unix mailboxes and Google Takeout

May grow to many gigabytes

The source archive remains read-only

Questions about this workflow

Why not open MBOX in a text editor?

You can, but attachments are encoded and message boundaries, MIME structure, and character sets make large archives hard to navigate manually.

Does MBOX contain folders?

A single MBOX is usually one flat message sequence. Some exports use multiple MBOX files to represent folders or labels.