Getting mail into an archive is only useful if you can get the right pieces back out in a form the next person can open. A colleague wants a PDF, an analyst wants CSV, opposing counsel wants Bates-numbered pages, and your own future self wants something that still opens in a decade. This post walks through every export format in mailin and the situation each one is built for.
Per-email formats: EML, PDF, TIFF and MSG
These four export a single message, or each message in a selection, as its own file.
- EML is the standard RFC 822 message file. It preserves headers, body and attachments as a real message, and nearly every mail client on any platform can open it. Use it when the recipient needs the message itself rather than a picture of it.
- PDF is for reading and printing. It is the format to send to someone who only needs to see the message, and it is the base for the Bates-stamped production described below.
- TIFF is an image format. Choose it only when a downstream system specifically asks for it.
- MSG is the Outlook single-message format. Use it when the recipient lives in Outlook and wants to open the message there.
Document and data formats
The second group exports a set of messages, or data derived from them, as a single document or dataset: Word, CSV, JSON, Markdown, plain text, MBOX and portable HTML.
MBOX is the one to reach for when you want a complete, re-importable copy of a mailbox. It is an open format, mailin can read it back, and so can most mail clients. Portable HTML produces a self-contained page you can hand to someone who has no mail software at all.
CSV and JSON are for analysis. CSV opens in any spreadsheet and is the natural export for message metadata or for PII findings, which mailin can write out grouped by type with source and risk. JSON keeps structure intact for scripts and other tools. Word, Markdown and plain text suit reports and notes where the content will be edited further.
Two smaller formats round this out. vCard exports contacts extracted from message headers, so you can rebuild an address book from an old archive. ICS exports calendar items so meeting details survive the move.
Attachments in bulk
When the thing you need is the spreadsheets and contracts rather than the messages around them, bulk attachment download pulls every attachment from a selection in one pass. Combined with the attachment filter and the attachment type and size breakdown in analytics, it is the quickest way to recover files from an archive without opening messages one at a time.
Legal production: Bates PDF and load files
Production for litigation has its own conventions, and the Professional tier covers the common ones. Bates-stamped PDF applies a sequential identifier to every page, with a configurable prefix and padding so the numbering matches whatever scheme the matter uses. Concordance and Relativity load files accompany the documents for loading into review platforms that use them.
Redacted exports let you remove or mark personally identifiable information before anything leaves the archive, which pairs with mailin's on-device PII detection and its GDPR data-subject-access reporting. The guided Production Run workflow strings these together: assemble a batch, review and code, build the privilege log, apply Bates numbers and redactions, then produce. The Bates numbering and Concordance post goes deeper on the settings.
These features are designed to support common records-integrity and eDiscovery workflows. Admissibility of digital evidence is jurisdiction-specific and depends on factors beyond any single software tool; consult qualified legal counsel for evidentiary use.
Forensic reports and signed exports
For investigations, the question is less whether the other side can read the material and more whether anyone can show it was not altered. mailin generates forensic reports that include SHA-256, SHA-1 and MD5 hash manifests for the exported material, so a recipient can recompute the hashes and compare. Every email is also hashed with SHA-256 at import, and mailin can re-verify those hashes later.
Exports can also be cryptographically signed with Ed25519, so a signature travels with the package and can be verified independently. This is a Professional-tier feature and sits alongside the HMAC-chained audit log and chain-of-custody tooling covered in the chain of custody post.
Reports, jobs and the experimental PST export
Beyond messages, analytics reports are exportable, and every guided workflow job saved in Documents & History can be exported to CSV. Documents & History also produces cross-document reports and end-of-day case activity reports.
One format deserves a caution. mailin has a PST export, but it is experimental and may not produce a file that Outlook will open. If your goal is to get mail back into Outlook, MSG for single messages or EML and MBOX for bulk are the dependable routes.
On tiers: all export formats are included from the Personal tier. Bates numbering, Concordance export, redaction and Ed25519-signed exports require Professional. The pricing section lists current prices.
FAQ
Which format should I use for a long-term backup?
MBOX for the whole mailbox, or EML per message. Both are open standards, keep attachments and headers, and can be re-imported into mailin or most mail clients.
What do I send to a lawyer or a review platform?
Bates-stamped PDF with Concordance or Relativity load files, produced through the Production Run workflow on the Professional tier. Ask the receiving side which load file format they expect.
Can I export to PST?
There is an experimental PST export, but it may not open in Outlook. Use EML, MSG or MBOX instead when reliability matters.