Is it safe to open confidential or legal PST files in OnlinePSTViewer.com?

Yes, 100%. OnlinePSTViewer.com operates on an air-gapped client-side model engineered by Prismmigration. When you select a file, the browser reads it directly into local memory using HTML5 File API and Web Workers. Zero file data, email content, or metadata is ever transmitted over the internet.

Can I open PST files on Mac, Linux, or Chromebook?

Yes! Because OnlinePSTViewer.com runs inside modern web browsers (Chrome, Edge, Safari, Firefox), you can open and read Outlook PST and OST files seamlessly on macOS, Linux, ChromeOS, iPad, and Windows without needing Microsoft Office or Outlook installed.

What is the difference between PST and OST files?

PST (Personal Storage Table) files are used by Microsoft Outlook for archiving and POP3 email accounts. OST (Offline Storage Table) files are cached local copies created by Exchange, Office 365, and IMAP accounts. OnlinePSTViewer.com parses both formats seamlessly.

Is there a file size limit for PST archives?

There are zero file size limits. OnlinePSTViewer.com utilizes client-side chunked byte slicing directly from your hard drive, meaning multi-gigabyte PST files of any size (50 GB, 100 GB+) open smoothly without overwhelming browser memory or uploading data to servers.

How can I open an MBOX file without installing Thunderbird?

OmniPST MBOX Viewer lets you open and read .mbox and .mbx files directly inside any modern web browser without downloading Thunderbird or desktop software. Simply drag and drop your file to browse messages immediately.

Can I open Google Takeout Gmail archives with this viewer?

Yes! Google Takeout exports all your Gmail messages as an MBOX file. OmniPST parses Google Takeout archives seamlessly, preserving original sender details, formatting, timestamps, and attachments.

Is my MBOX file uploaded to any remote server?

No. OmniPST runs 100% inside your browser memory (RAM). Zero bytes of your emails or attachments are ever transmitted over the network.

100% Free • Private In-Browser Viewer

The Fastest Online MBOX File Viewer

Open, view, search, and export Google Takeout, Mozilla Thunderbird, and Apple Mail MBOX archives directly in your web browser without installing heavy software.

Drag & Drop your MBOX file here

Supports all MBOX formats: Google Takeout, Thunderbird, Apple Mail, Eudora & Opera (.mbox, .mbx, .mbs)

No data sent to server (100% RAM)Sub-second stream decodingGoogle Takeout & Thunderbird

Engineered for High-Speed MBOX Mailbox Inspection

Everything you need to inspect, search, and export Google Takeout and Thunderbird mailboxes without desktop bloat.

1. 100% Client-Side Privacy

Your emails and attachments are parsed locally in browser memory. Zero bytes are uploaded to remote servers, ensuring GDPR and HIPAA compliance.

2. Live Search Highlighting

Instantly locate senders, subjects, and keywords across your entire mailbox with dynamic glowing search-term highlights.

3. 1-Click Attachment Downloads

Preview embedded PDFs, images, and documents directly, or download individual files and batch export clean EML messages.

4. Rich HTML Newsletter View

Inspect multipart HTML formatting, inline logos, recipient CC/BCC headers, and clean responsive mobile email templates.

5. 1-Click PDF Printing & Save

Export legal discovery emails, corporate compliance notifications, or tax invoices to PDF with crisp vector resolution.

6. Superhuman Keyboard Flow

Fly through your messages with standard hotkeys: Up/Down to navigate, / to search, f for fullscreen reading, and ? for cheatsheet.

Unrivaled Speed & Privacy

OmniPST vs Other MBOX Viewers

Why users and IT administrators prefer OmniPST over Thunderbird or server-based uploaders.

Feature & Security Capabilities	OmniPST MBOXYou	Mozilla Thunderbird	Cloud Uploaders
Zero Server Upload (100% In-Browser Privacy) Archive decoded in browser RAM. Zero network transmission.
No Desktop Software Installation Required Thunderbird requires downloading 200MB installer and local config.
Instant Google Takeout Mailbox Parsing Thunderbird requires ImportExportTools NG add-on to read Takeout.
Live Search Keyword Highlighting Glowing text matches in subject, body, and sender names.
1-Click PDF & EML Message Export Export individual messages with full styling and attachments.
Power Keyboard Navigation (↑/↓, /, f, ?) Navigate emails at Superhuman speed without touching your mouse.
Pricing & Account Barrier Open unlimited mailboxes without entering email or credit cards.	100% Free & No Signup	Free (Heavy App)	Paid / File Size Capped

How to Open Google Takeout MBOX Files in 3 Steps

Access your Gmail backup without downloading third-party software

Select Your Archive

Drag and drop any .mbox or .mbx file onto this window.

Instant Local Stream

Our browser engine indexes message boundaries and MIME parts in local RAM.

Search & Export

Read threads, download attachments, and export individual emails to EML or PDF.

MBOX FAQs & Help

Frequently Asked Questions

Everything you need to know about opening MBOX archives online safely.

OmniPST MBOX Viewer allows you to open, search, and export Google Takeout archives directly inside your browser. You do not need to install Mozilla Thunderbird, Apple Mail, or any third-party desktop software. Simply drag and drop your .mbox or .mbx file, and our client-side engine parses all emails, threads, and attachments instantly in memory.