Split a Thunderbird, Apple Mail, Gmail Takeout or Google Vault .mbox archive into individual .eml messages without installing Thunderbird or uploading your mail to a conversion site. Messages come out bit-exact, named by subject, packed in a ZIP — entirely in your browser.
Detailed side-by-side format architecture for MBOX Document (.mbox) and ZIP Document (.zip). Every conversion executes strictly within isolated browser memory without network transit.
Drag and drop your .mbox file onto the working surface or use the system file dialog. File magic bytes are verified locally on device.
Select a quality preset (Lossless, Visually Lossless, Balanced, Smallest) or adjust advanced encoding switches in the options panel.
Click CONVERT to execute local WebAssembly compilation. Save the finished .zip directly to local storage, or stage it for chaining.
Prefer local shell scripting? Run this standard POSIX command on your machine to achieve equivalent transcoding without a web interface:
# Convert MBOX to ZIP locally
pandoc input.mbox -o output.zipWorking with files across multiple web pages? The official convrtr Chrome Extension adds native Side Panel docking, right-click context menu media extraction, and visible viewport capture. Powered by the same zero-upload client-side WebAssembly engine.
Single-message .eml files are independently searchable, shareable, and ingestible by eDiscovery, phishing-analysis and archival pipelines (paperless-ngx and friends). Splitting also rescues one mailbox from a client you no longer run.
Yes — splitting cuts between messages and unescapes >From lines only. Every message's headers, HTML bodies, MIME parts and attachments are byte-identical to the source mailbox.
Standard mboxrd files from Thunderbird, Apple Mail, Gmail Takeout, Google Vault, Proton Mail export and MailStore. Files without From-separator lines are rejected with a clear error rather than guessed at.
No. Splitting and zipping run entirely inside your browser — your correspondence never touches a server.
MBOX Document (MBOX) and ZIP Document (ZIP) serve distinct roles across the digital workflow. Converting to ZIP provides optimized compatibility, modern compression efficiency, or standardized playback across web browsers, operating systems, and media production environments.
The output format (ZIP) is inherently lossless or supports lossless operation. Your original visual or audio fidelity is mathematically preserved without quantization artifacts.
Never. convrtr is architected with a strict zero-upload model. All processing, decoding, decompression, and encoding happen 100% locally on your machine using sandboxed WebAssembly and Web Workers. Your data never touches an external server, database, or analytics collector.
You can execute this conversion locally via command-line utilities such as ffmpeg, cwebp, or ImageMagick. For example: see the developer terminal recipe provided in the technical specifications dossier above. convrtr provides the identical local-first capability directly inside your browser without installing CLI packages.
Yes. You can drop multiple .mbox files into the instrument to process them concurrently in browser Web Workers, or click 'Open in Master Studio' to queue mixed formats, configure individual targets, and export as a single ZIP archive.
Convert web media, local files, and document assets directly in Chrome Side Panel using client-side WebAssembly, zero-server uploads, and the official convrtr browser extension.
A byte-level walkthrough of the MLW container format: the Root marker, the filename block, the AES-GCM payload, and the one part of the layout nobody has documented.
MLW uses a single fixed encryption key shared across every install of the app. What that means for whether unwrapping it counts as DRM circumvention — in plain English, not legal advice.