Mailward
Open and search PST or OST files in your browser without Outlook
Mailward lets you open, browse, search, and export Outlook PST and OST files directly in your browser. It also reads OLM (Outlook for Mac), MBOX (Google Takeout), EML, and MSG files. It parses archives locally with the File API and a Web Worker, keeping your data on your device and allowing multi-gigabyte files to load without exhausting memory. Use it on macOS, Windows, Linux, or ChromeOS to view folders, read messages with attachments, and run full-text searches for free. Upgrade to Pro with a one-time $19 license for batch-converting folders to MBOX or EML and exporting search results in one click.