outlook-pst-go

A pure Go library for reading and writing Microsoft Outlook PST (Personal Storage Table) files.

Features

• Read and write PST files
• Create new PST files from scratch
• Both ANSI and Unicode PST formats supported
• All encryption methods (none, permute, cyclic)
• Pure Go - no CGO dependencies
• Transaction safety with two-phase commit
• Lazy loading for efficient memory usage
• Go 1.23+ iterators for idiomatic iteration
• RTF decompression for message bodies
• Named properties for custom MAPI properties
• Search folder support
• Granular error types for precise error handling

Quick Example

Reading a PST File

pst, err := outlookpst.Open("archive.pst")
if err != nil {
    log.Fatal(err)
}
defer pst.Close()

root, _ := pst.RootFolder()
for folder, _ := range root.Subfolders() {
    name, _ := folder.Name()
    fmt.Printf("Folder: %s\n", name)

    for msg, _ := range folder.Messages() {
        subject, _ := msg.Subject()
        fmt.Printf("  - %s\n", subject)
    }
}

Creating a New PST File

// Create a new PST file
pst, err := outlookpst.Create("new-archive.pst", disk.FormatUnicode)
if err != nil {
    log.Fatal(err)
}
defer pst.Close()

// Start a write transaction
ctx, err := pst.BeginWrite()
if err != nil {
    log.Fatal(err)
}

// Create a folder
root, _ := pst.RootFolder()
inbox, err := ctx.CreateFolder(root, "Inbox")
if err != nil {
    ctx.Rollback()
    log.Fatal(err)
}

// Create a message
_, err = ctx.CreateMessage(inbox).
    SetSubject("Hello World").
    SetBody("This is a test message.").
    SetFrom("sender@example.com", "Sender Name").
    AddTo("recipient@example.com", "Recipient").
    Build()
if err != nil {
    ctx.Rollback()
    log.Fatal(err)
}

// Commit the transaction
if err := ctx.Commit(); err != nil {
    log.Fatal(err)
}

Supported Formats

Format	Version	Status
ANSI PST	14-15	✅ Supported
Unicode PST	20-23	✅ Supported
OST	Any	✅ Supported (read-only)

Encryption Support

Method	Status
None	✅ Full support
Permute	✅ Full support
Cyclic	✅ Full support

Feature Support

Feature	Read	Write
Folders & Subfolders	✅ Full	✅ Full
Messages	✅ Full	✅ Full
Attachments	✅ Full	✅ Full
Recipients	✅ Full	✅ Full
RTF Decompression	✅ Full	-
Named Properties	✅ Full	⚠️ Partial
Search Folders	✅ Full	-
Multi-value Properties	✅ Full	⚠️ Partial
Create PST Files	-	✅ Full
Transaction Safety	-	✅ Full
Crash Recovery	-	✅ Full

Architecture

The library implements a 4-layer architecture matching the MS-PST specification:

┌─────────────────────────────────────────┐
│  Messaging Layer (PST, Folder, Message) │
└─────────────────────────────────────────┘
                    ↓
┌─────────────────────────────────────────┐
│  LTP Layer (PropertyBag, Table, Heap)   │
└─────────────────────────────────────────┘
                    ↓
┌─────────────────────────────────────────┐
│  NDB Layer (Database, Node, Block)      │
└─────────────────────────────────────────┘
                    ↓
┌─────────────────────────────────────────┐
│  Disk Layer (Header, Pages, Encryption) │
└─────────────────────────────────────────┘

Getting Started

See the Installation guide to get started.

Specification Compliance

This library implements the [MS-PST] specification from Microsoft. See the Specification Reference for details.

License

MIT License