Open Email Archive Format

MBOX Viewer

Search and browse MBOX email archives from Thunderbird, Apple Mail, Gmail Takeout, and any other MBOX-compatible client, instantly, in your browser.

What is an MBOX file?

MBOX is an open, widely-supported email storage format used by Mozilla Thunderbird, Apple Mail, Gmail (via Google Takeout), Evolution, Eudora, and many other email clients. Unlike proprietary formats like PST or OST, MBOX is a plain-text format where individual email messages are concatenated into a single file. This makes MBOX files highly portable but also very large. A full Gmail export can easily be tens of gigabytes. Evermail handles MBOX files of any size and from any source.

Why use an online MBOX viewer instead of a desktop app?

Desktop MBOX viewers like Thunderbird require installation, profile configuration, and don't offer search across multiple archives. An online MBOX viewer lets you upload once and search your entire email history from any browser — no software to install, no file format conversion, and no storage limits on your local machine. Evermail adds AI-powered summaries and attachment search on top.

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Works anywhere

Access your MBOX archive from any device with a browser — Mac, Windows, Linux, or mobile. No installation, no profile setup.

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Search across multiple archives

Upload archives from different clients and search them all at once. Desktop tools are limited to one profile at a time.

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AI-powered summaries

Evermail summarizes long threads automatically. Desktop viewers show you raw email — you do the reading.

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Attachment search

Find every email with a specific attachment type or filename across your entire archive in seconds.

Evermail + MBOX

How Evermail handles MBOX files

Upload once. Search forever. No conversion, no special software needed.

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Upload your MBOX file

Upload your MBOX file from Thunderbird, Apple Mail, Gmail Takeout, or any other source. Single files up to 100 GB on Enterprise plans.

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Fast parsing & indexing

Evermail splits, parses, and indexes every message in the MBOX archive, including multi-part MIME messages, attachments, and headers.

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Full-text search

Search across all messages with fast full-text search. Filter by sender, date, subject, attachment, or folder, and generate AI-assisted summaries when you need a recap.

Why Evermail

Key features for MBOX archives

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Works with all MBOX sources

Thunderbird, Apple Mail, Gmail Takeout, Evolution, Eudora, Claws Mail: any MBOX file from any client is supported.

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AI-assisted summaries

Generate concise summaries of long threads and emails, so you can catch up on a conversation without reading every message.

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Attachment search

Search by attachment name or type. Find every email with a PDF, spreadsheet, or image attached, across your entire archive.

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Folder & label preservation

Thunderbird folders and Gmail labels are preserved after import so you can browse your archive just like the original.

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Export individual messages

Download any email as EML. Export filtered results as a new MBOX for migration or long-term archiving.

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GDPR-compliant, EU-hosted

Your MBOX data is stored exclusively on EU infrastructure. Full GDPR compliance built in from day one.

Open your MBOX archive today

No special software. No conversion. Upload, index, and search. Free to start.

Get started free →
Comparison

Evermail vs desktop MBOX viewers

See how an online MBOX viewer compares to traditional desktop clients like Thunderbird.

Feature Evermail Online Desktop Viewers
Installation required No Yes
Cross-device access Yes No
Full-text search Yes Limited
AI summaries Yes No
Handles 50+ GB archives Yes Rarely
GDPR compliant Yes Varies
FAQ

Common questions about MBOX files

Where can I find my MBOX files from Thunderbird?
In Thunderbird, your MBOX files are stored in your profile folder (typically ~/AppData/Roaming/Thunderbird on Windows or ~/Library/Thunderbird on macOS). Each folder in Thunderbird corresponds to a file without an extension, which is the MBOX format.
Can I upload a Gmail Takeout MBOX file?
Yes. Google Takeout exports Gmail as MBOX files inside a ZIP archive. You can upload the MBOX files directly to Evermail. We also have a dedicated Google Takeout guide. See our Google Takeout page.
My MBOX file is very large (50+ GB). Can Evermail handle it?
Yes. Evermail is designed for large archives. Files up to 10 GB are supported on Team, and up to 100 GB on Enterprise. For very large files, upload may take some time but indexing happens in the background.
How do I open an MBOX file without Thunderbird?
Upload it to Evermail. No email client needed — Evermail parses and indexes MBOX files directly in your browser. You can search, browse, and export messages without installing any software.
Is there a free online MBOX viewer?
Yes. Evermail's free plan lets you upload up to 1 GB of MBOX files and search them online at no cost. No credit card required.
Can I view MBOX files on Mac?
Yes. Evermail is browser-based and works on Mac, Windows, Linux, and mobile. Upload your MBOX file from any operating system.
How do I search inside a large MBOX file?
Upload it to Evermail. The file is indexed automatically, and you can search by keyword, sender, date, subject, or attachment across the entire archive in seconds.
Is my data safe with Evermail?
Yes. Evermail is EU-hosted and GDPR compliant. Your emails are stored on Azure EU infrastructure and never leave the EU. You can choose from three security levels per mailbox, including client-side zero-access encryption.
How much does it cost?
Evermail has a free plan (1 GB, 30-day retention) to get started at no cost. Paid plans start from €4.99/month for 5 GB with permanent retention. See full pricing →