Tiny Online Tools
What a PST actually is
A .pst is not a document. It is a small database: a header, two B-trees — the node B-tree and the block B-tree — and a heap layered over the blocks in which every folder and every message keeps its MAPI properties. Outlook is the usual way to read one, and if you do not have Outlook there is normally nothing you can do with the file at all.
What this reads
The header first: the !BDN signature, whether the file is a PST or an OST, whether it uses the ANSI or the Unicode layout, which block encoding it uses, how large the header claims the file is against how large it really is, and the two B-tree root references.
Then both B-trees, in full and with page-level validation, followed by the heap-on-node and the property contexts inside it. That is where folder names, message counts, unread counts, container classes, subjects, senders, recipients-as-displayed, dates, sizes and message classes actually live — so the folder tree and the message index here are read out of the file, not guessed. NDB_CRYPT_PERMUTE blocks are decoded, and values spread across several blocks are reassembled through their data trees and subnode trees.
What it does not read
Attachment payloads, recipient tables, and the table contexts behind a folder's contents view. A message body is shown only when it was stored as a property on the message node itself, which is common for short messages and not for long ones — when it was not, the tool says so instead of showing an empty box.
Two layouts are detected and reported rather than guessed at: the 4K page geometry Outlook 2013 introduced for OST files, which sits outside the published MS-PST specification, and NDB_CRYPT_CYCLIC, whose substitution tables were never published. For either one you still get the full header, and a warning explaining why the rest is missing.
About PST "passwords"
A PST password is a property stored inside the file. It is not a key and it encrypts nothing. A password-protected PST is read here exactly like any other, and nothing is being cracked or bypassed — Outlook simply chooses to honour a flag that any reader is free to ignore.
Privacy
The archive is parsed in your browser with no network requests at all. Mail is personal; none of it leaves the page.