Audit-Proof Email Archiving

"Revisionssicher", usually translated as audit-proof, is not defined in any German statute. It sums up what the Commercial Code, the Fiscal Code and GoBD require from an archive: a tax audit must be able to rely on the archive being complete and unchanged.

Legal basis

§ 239 (3) HGB and § 146 (4) AO: records must not be changed in a way that hides the original content.
§ 257 HGB and § 147 AO: business letters, accounting vouchers and tax-relevant documents are kept for 6, 8 or 10 years.
GoBD: electronic records are kept in their original format, unalterable, complete and machine-readable.

Five criteria

Criterion	What it means for email
Complete	Every email is captured before a user can delete it
Unalterable	Content, headers and attachments stay exactly as received
Protected from deletion	Deletion only after the retention period
Findable	Every email can be found in seconds for the whole period
Traceable	Access and settings changes are logged

Why mailbox, PST file and backup fall short

In a mailbox, users delete emails with one click, and the trash gets emptied. An Outlook PST file can be opened, edited and copied without a trace. A backup only holds what was there when it ran. None of them meets all five criteria.

How EasyMailArchive works

Capture in the mail flow. A BCC or journal rule on your mail server sends every email to your relay address [email protected] the moment it is sent or received.
Original storage. The email is stored unchanged, with a SHA-256 checksum per message.
Encryption. AES-256 with a separate key per customer, stored in Germany, a separate database per customer.
No deletion. There is no delete function for single emails. When the retention period you set ends, the system deletes automatically. A legal hold (Business and up) stops that too.
Log. Every action in the archive is logged. Export the log as CSV.
Export for the auditor. Original EML, or PDF with checksums.

Setup takes a few steps: create an account, add the relay address to a BCC rule, send a test email. See the setup guide for your system.

Your part

Software alone does not make an archive audit-proof. You need procedural documentation that describes how emails are captured, kept and deleted, and you need to make sure the BCC rule stays active.

See pricing or try it free for 30 days.

This article summarises the law in general terms and is not legal or tax advice.

Frequently Asked Questions

What does audit-proof mean for email?

Every email is captured completely, stored in its original form, cannot be changed or deleted unnoticed, and stays findable and readable for the whole retention period. The German term revisionssicher is not in the statute, but it sums up the requirements of HGB, AO and GoBD.

Is a backup audit-proof?

No. A backup saves a point in time. Emails that arrive and are deleted between two backups are missing. Backups can also be overwritten, and single emails are hard to find in them.

How do I prove an email was not changed?

EasyMailArchive stores a SHA-256 checksum for every email. The PDF export contains these checksums. You can also export the original email as an EML file.

Can administrators delete archived emails?

Not in EasyMailArchive. There is no delete function for single emails. Emails are deleted automatically only when their retention period ends and no legal hold applies.