A complete, native MBOX toolkit

A streaming parser with a 1 MB buffer opens files from a few KB to 50+ GB without ever loading them into RAM.

A binary index with SHA-256 validation makes every re-open take under a second, regardless of size.

Even a 50 GB archive stays under 600 MB of RAM thanks to on-demand streaming and an LRU message cache.

Deep-scan recovery re-detects lost message boundaries and exports a repaired copy — the original file is never modified. (Pro)

Use from:, to:, subject:, body:, date:, has:attachment, size:>, OR, negation and exact phrases — or the visual filter sheet.

Reads Gmail labels straight from Takeout. Browse by label in the sidebar with live message counts.

The JWZ algorithm groups messages into conversations with visual reply chains up to four levels deep.

Three new ways to inspect a message: a Properties panel, the MIME part tree and a raw hex dump — ideal for technical or forensic work.

Export to EML, CSV (Excel-ready, UTF-8 with BOM) or plain text, and extract attachments in bulk.

Combine multiple MBOX files into one, with optional Message-ID deduplication. Export a single label as its own MBOX.

View attachments inline, preview with Quick Look (Spacebar), save individually or in bulk, or drag straight to Finder (Explorer on Windows).

Export any message to a self-contained, multi-page PDF with the same layout as printing. One message is free; batch export is Pro.

Save any message as a self-contained HTML file with images embedded and attachments as downloadable links — it opens anywhere. One message is free; batch is Pro.

Native on Mac (SwiftUI + AppKit) and Windows (WinUI). Dark mode, drag & drop, system share, print and full keyboard navigation. No Electron, no Java.

Everything runs locally. No cloud, no telemetry, no account. Remote images blocked and HTML sanitized by default.

Drop MBOX or EML files onto the app to open them, and drag messages out as .eml or attachments to Finder.