audit-viewer

A web-based viewer for Microsoft 365 audit logs with powerful faceted filtering capabilities.

Features

✨ Faceted Filter Sidebar

• Filter audit logs by multiple criteria simultaneously
• Real-time filtering without page reload
• Responsive design - works on desktop and mobile devices
• URL-based filter state (shareable filtered views)

📊 Large File Support

• Handles CSV files with hundreds of thousands of rows
• Chunk-based processing for efficient memory usage
• Progressive loading with real-time progress updates

Filter Types

• ✅ Operation: Checkbox filters for common operations (FileAccessed, FileModified, FileDeleted, etc.)
• 👤 User: Searchable user list with autocomplete
• 📄 File Name: Text search for file names
• 🌐 Site URL: Text search for SharePoint site URLs
• 🔢 IP Address: Filter by client IP address
• 📅 Date Range: Select date range with from/to pickers

Usage

1. Open viewer.html in a modern web browser
2. Click "Choose File" to upload a CSV export of Microsoft 365 audit logs
3. Use the filter sidebar to refine results:
   • Check/uncheck operations
   • Search for specific users, files, or sites
   • Set date ranges
4. View filtered results in real-time
5. Click on "🔍 View" to see detailed AuditData for any record

Mobile Usage

On mobile devices, tap the "☰ Filters" button in the top-left corner to open the filter sidebar. Tap outside the sidebar or on the overlay to close it.

Sharing Filtered Views

Filters are automatically saved to the URL. Copy the URL to share a specific filtered view with others.

CSV Format

The viewer expects CSV files with these columns:

• CreationDate: Timestamp of the audit event
• UserId: User who performed the action
• Operation: Type of operation performed
• AuditData: JSON string containing detailed audit information

Technologies

• AG-Grid Community - Data grid
• PapaParse - CSV parsing with chunk-based processing for large files
• Vanilla JavaScript (no build process required)

Performance

The viewer uses PapaParse's chunk-based parsing to efficiently handle large CSV files:

• No hard limit on file size or row count (previously limited to ~50,000 rows)
• Progressive loading keeps the UI responsive during file processing
• Web Workers offload parsing to a background thread