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.

100% Free • Private In-Browser Viewer

Free Online PST & OST Viewer

Open, view, and search Microsoft Outlook emails, contacts, calendars, and attachments directly in your web browser. No software installation needed.

Drag & Drop your PST or OST file here

Supports all Outlook PST & OST files with no file size limits. 100% private in your browser.

100% Private (No uploads)Instant in-browser loadingAll Outlook Versions Supported

Unrivaled Speed & Privacy

How OmniPST Compares to Competitors

See why IT administrators, legal discovery teams, and privacy-conscious users prefer OmniPST over legacy software and cloud upload services.

Feature & Security Capabilities	OmniPSTYou	GoldFynch	Aspose / SysTools
Zero Server Upload (100% Client-Side Privacy) Your confidential PST/OST archive never leaves your device memory.
Full Support for All 5 PST Item Types (Mail, Contacts, Calendar, Tasks, Notes) Dedicated native viewers for appointments, address book vCards, tasks, and notes.
Instant Global Multi-Folder Search Simultaneously search through all folders and subfolders in seconds.
Message Details & Technical Inspector Inspect complete email properties, delivery headers, and technical metadata.
Power Keyboard Navigation (↑/↓, /, Fullscreen) Blazing fast keyboard shortcut controls modeled after Outlook & Gmail.
Zero Account Signup or Email Gatekeeping Open and inspect files immediately without entering email or passwords.
Cost / Pricing Full unrestricted viewing without hidden paywalls.	100% Free	Trial only (Paid)	Freemium / Limited

How to Open a PST File Without Microsoft Outlook

Three simple steps to access your email archive on Mac, Windows, Chromebook, or Linux

Select Your Archive

Drag and drop any .pst or .ost file onto the browser window.

Instant In-Browser Loading

Your browser safely reads folder trees, messages, and attachments locally on your device.

Search & Export

Search keyword queries, download attachments, and export individual messages to EML or PDF.

Frequently Asked Questions

Everything You Need to Know

Answers to common questions about opening, viewing, and exporting Outlook PST files.

Online PST Viewer allows you to open, browse, search, and export Microsoft Outlook .PST and .OST files directly inside your web browser. You do not need Microsoft Outlook, Office 365, or any third-party desktop software installed. Simply drag and drop your file to access your emails, contacts, appointments, tasks, and notes immediately.