One Scales Launches MBOX Viewer, a Private in-Browser Tool for Reading Gmail Emails

AUSTIN, Texas - Aug. 3, 2026 - PRLog -- One Scales Inc. today announced the release of MBOX Viewer, a web-based tool that opens and reads MBOX email archives entirely inside the user's browser — private by design, with no file ever uploaded to a server.

MBOX is the format most people encounter when they use Google Takeout to export their Gmail — Takeout packages an entire mailbox into a single MBOX file, which is also the internal storage format for Thunderbird and Apple Mail. Because that file can bundle tens of gigabytes of messages into one enormous archive, most people have no simple way to open it without installing dedicated software or handing the file over to a third-party conversion site.

MBOX Viewer, addresses both problems at once. The tool reads a file in small pieces directly from the user's machine using standard browser file APIs, so archives of 10GB, 50GB or more can be opened without running out of memory — and without a single byte of the file ever leaving the computer. There is no upload step, no account, and no server in the middle. The mailbox is read, searched and exported entirely on-device, start to finish.

Key capabilities include:

- Browse and search — A familiar two-pane mail layout with search by sender or subject, and filtering by date range.
- Export to common formats — CSV that opens directly in Google Sheets, Excel or Numbers, PDF for printing or filing, EML for re-importing into Thunderbird, Outlook or Apple Mail, and a slimmed-down MBOX for splitting large archives.
- Attachment extraction — View and download individual attachments, or pull every attachment across an entire mailbox into a single ZIP file, filtered by type.
- No install, no account — Users simply choose a file and the tool opens it locally; nothing to download or sign up for.

"Most MBOX tools ask you to upload your entire email history to a company you've never heard of," said a spokesperson for One Scales. "We built this so that step doesn't exist. There's no server for the file to go to — your browser does all the reading, searching and exporting locally, and your mailbox never leaves your machine."

Reading a mailbox and exporting a single message require no payment. A one-time $29 unlock removes file-size limits and enables bulk exports and attachment extraction, with no subscription required.

MBOX Viewer is available now at https://mbox.onescales.com/ and works best in desktop versions of Chrome or Edge.