extension Chrome Extension and Web App · by Cloud Captains

Mbox Viewer View your .mbox email archives instantly and securely

A 100% private, client-side tool to read .mbox files from Google Takeout or other backups. All processing happens in your browser: your data never, ever leaves your computer.

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lock100% private computerClient-side storageUp to 25GB euroFree

A full-featured email toolbox

Everything you need to manage your email archives, built with privacy as the priority.

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Privacy first

Your files are never uploaded. All processing happens locally in your browser, with storage only in IndexedDB on your own device.

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Dual-Mode Engine

Switches intelligently between RAM mode for speed and database mode for archives over 1GB. Roughly a million emails every five minutes.

Powerful search and filters

Search your archive by sender, subject and date. Filter by attachments, source file or date range and find any email in seconds.

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Export options

Export emails as .eml, .html or .pdf. Manage attachments safely from within the viewer.

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Security insights

Inspect SPF, DKIM and DMARC status per email to judge the authenticity of messages.

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Raw source view

Switch to the full message source with all headers, ideal for technical analysis.

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Read-only

Your original files are never modified. Load multiple files or entire folders at once.

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Usable anywhere

Light and dark theme, optimized for Chromebooks and also works without an internet connection.

Simple, powerful, visual

From backup file to searchable archive in three steps.

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1. Launch and Load

Drag your .mbox files or entire folders into the viewer, or pick them via the file selector. Nothing is uploaded.

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2. Browse and Search

Browse your archive in a clean list with a reading pane and search everything with the powerful search function.

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3. Filter, View, Export

Filter by sender, attachments or date, view emails safely and export as .eml, .html or .pdf.

A glance inside Mbox Viewer

Clean interface, powerful filters, safe preview.

Dropzone with filters: drag files or folders straight into the viewer

Email list with search, filters and reading pane side by side

Email view with preview, raw source and export to PDF, .eml or .html

Formats and platforms

Built on the mbox standard, broadly usable.

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Supported formats

Standard .mbox files (RFC 4155): Google Takeout exports and archives from Thunderbird, Apple Mail and Eudora.

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Not supported

Outlook .pst files are a closed format and cannot be opened.

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Platforms

Windows, macOS, Linux and ChromeOS, in Chrome and other modern browsers. Limited support on iOS and Android.

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Limits

Archives up to 25GB, depending on your RAM and CPU. No hard limit on the number of emails.

Up and running in one minute

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Open the Chrome Web Store

Click the install button on this page to go straight to the Mbox Viewer page in the Web Store.

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Add to Chrome

Click "Add to Chrome" and confirm. The extension is ready to use seconds later.

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Drop your archive in

Open the viewer and drag your .mbox file or entire folder into the dropzone. Instantly searchable.

Documentation and knowledge base

Our docs environment contains a step-by-step guide plus an extensive knowledge base about mbox, eml and Gmail archives.

menu_book Open the docs

Frequently Asked Questions

Is Mbox Viewer free? expand_more

Yes, the tool is completely free to use via the Chrome Web Store.

Where does my data go? expand_more

Nowhere. All processing happens in your browser and your data never leaves your computer. We have no access to your files, so we have nothing to see or sell.

Which files can I open? expand_more

Standard .mbox files (RFC 4155), including Google Takeout exports and archives from Thunderbird, Apple Mail and Eudora.

Can I open Outlook .pst files? expand_more

No. The Outlook .pst format is a closed format and is not supported.

How do I open my Gmail archive from Google Takeout? expand_more

Download your Takeout export, unzip it and drag the .mbox file into the viewer. Your mailbox is instantly searchable.

How large can my archives be? expand_more

The Dual-Mode Engine automatically switches to database mode for archives over 1GB and supports files up to 25GB, depending on your RAM and CPU.

Does the viewer modify my original files? expand_more

No. Mbox Viewer is fully read-only, your original backup stays untouched.

Can I load multiple files or folders at once? expand_more

Yes. Drag multiple .mbox files or an entire folder into the viewer and search everything in one overview. Folder support works in Chrome and Edge.

How do I export an email? expand_more

Open the email and choose export as .eml, .html or .pdf. Attachments can be downloaded safely as separate files.

Which devices does it work on? expand_more

Windows, macOS, Linux and ChromeOS, in Chrome and other modern browsers. The tool is optimized for Chromebooks and also works offline.

Questions or feedback?

Found a bug or have an idea for a new feature? We'd love to hear from you via the contact form.

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