About Mailward

Mailward is a set of local-first tools for opening and converting email archives — Outlook PST and OST, Outlook for Mac OLM, plus MBOX, EML, and MSG — directly in the browser. You can read, search, and export a decade-old mailbox on any machine, including a Mac or Chromebook that has never had Outlook installed.

Why it exists

Old mail archives usually resurface at the worst moments: an employee leaves, a lawyer asks for correspondence, a family member needs mail from a retired PC. The traditional options are to install and license Outlook just to open one file, or to upload years of private email to a stranger's "free online converter" and hope for the best. Neither felt acceptable, so we built the third option: a viewer that runs entirely on your own device.

How it works

When you pick a file, your browser reads it with the File API inside a Web Worker on your machine. Large archives are streamed in pages rather than loaded whole, which is how multi-gigabyte PST files stay usable. Nothing is transmitted: you can load the page, go offline, and keep working. There is no account, no queue, and no server that ever sees a message.

What it deliberately does not claim

• It reads healthy archives; it does not repair corrupted or password-encrypted files.
• It converts out of PST/OST into open formats (MBOX, EML, CSV); it does not write PST files.
• S/MIME-signed .msg content stays sealed in its smime.p7m wrapper — the cryptographic layer is not unpacked.

Who is behind it

Mailward is built and supported by Lei Wang, an independent developer (github.com/leivorn). Small product, direct support: bug reports and feature requests go straight to the person who writes the code — several shipped the same day they were requested.

Longer format notes — for example, how to check whether a copied PST is complete before trusting it — are published by the Mailward organization on GitHub at mailward.github.io/email-archive-formats, and the GitHub account above answers PST, OST and MSG questions in open-source mail projects, including the issue tracker of pst-extractor, the PST library Mailward is built on.

How it is funded

Reading and searching are free, and so is exporting three messages a day with their attachments. Batch conversion and bulk attachment export are a one-time paid license — no subscription. That license is the entire business model: Mailward makes money from software, not from your data.

Contact

Questions, bugs, or a format we should support next? See the contact page or email vertrigr@gmail.com.