Managed MailStore · German Data Centers

Audit-proof email archiving with MailStore - for GoBD and GDPR

We archive your emails automatically, completely and immutably - as a managed service from German ISO 27001 data centers. You get your own dedicated archive instance; we handle setup, operation and import.

from €3.99 per mailbox per month - storage, admin licence and operation included

Offer until 31 Dec 2026: setup and import of your existing emails up to 100 GB free of charge

Request a quoteView pricing
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For GoBD & GDPR
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Certified archiving software
MailStore is certified to IDW PS 880. The certificate confirms that the software enables GoBD-compliant email archiving - the technical foundation for your retention.
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AES-256 encrypted
Illustration: emails flow from a laptop into an encrypted, searchable archive in the data center
Hosted in German data centers
AES-256 encryption
All access logged
For GoBD & GDPR
i
Certified archiving software
MailStore is certified to IDW PS 880. The certificate confirms that the software enables GoBD-compliant email archiving - the technical foundation for your retention.
Pricing

Archive your mailboxes audit-proof - from the oneCorp Cloud

One price per mailbox per month - licence, 50 GB archive storage, archive administrator and operation included. The more mailboxes and the longer the term, the lower the price.

Offer until 31 Dec 2026: setup and import of your existing emails up to 100 GB free of charge - for orders placed by 31 Dec 2026.

Mailboxes
12 months
24 months
lower rate
3-9 mailboxes
For small teams
€5.49
/ mailbox
€5.29
/ mailbox
10-19 mailboxes
For growing teams
€4.99
/ mailbox
€4.79
/ mailbox
20-49 mailboxes
For mid-sized companies
€4.79
/ mailbox
€4.59
/ mailbox
50-99 mailboxes
For larger organisations
€4.49
/ mailbox
€4.29
/ mailbox
100+ mailboxes
For large organisations
Best price
€4.19
/ mailbox
€3.99
/ mailbox
Request a quote

Example: 10 mailboxes, 12-month term = 10 × €4.99 = €49.90/month - archive administrator and 500 GB pool included.

Storage Included
  • 50 GB of archive storage per mailbox in a shared pool*
  • + €4.99/month for each additional 100 GB

* We measure the archive size of the instance after de-duplication. If the pool is exceeded, the next 100 GB tier is charged automatically.

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50 GB per mailbox included
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Setup included with a 24-month term, otherwise €99 - free until 31 Dec 2026

Additional services

Storage expansion 100 GB (pool)
€4.99/month
Audit user (licence without storage)
€2.99/user/month
Additional admin user (licence without storage)
€2.99/user/month
Setup (instance, archive admin, mail system connection, import up to 25 GB)
€99 one-off with a 12-month term · included with a 24-month term · Offer until 31 Dec 2026: €0 incl. import of existing emails up to 100 GB
Import of existing emails above 25 GB (above 100 GB during the offer)
€0.79 per GB, minimum €49
Administration by oneCorp (configuration changes on request, up to 2 hrs/month)
€29/month
Configuration on demand
€89/hour, billed in 15-minute increments
System documentation (technical part of the procedural documentation)
€149 one-off, update €49
All prices per mailbox per month, including 50 GB storage and archive administrator. Minimum billing 3 mailboxes, tier prices apply to all mailboxes. All prices net plus statutory VAT. Our offers are directed exclusively at businesses, organisations (including non-profits) and public institutions, not at consumers.

What features does MailStore offer?

Thoughtfully designed features make professional email archiving efficient and effortless for your business. With MailStore, your email communication stays organized, secure and searchable at all times - a solid foundation for your legal retention obligations. The following overview shows which features stand out in particular.

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Automatic Archiving

Emails from mailboxes and PST files are archived automatically.
Pen and paper icon representing documentation

Retention According to Your Rules

Retention policies apply your periods automatically and protect against premature deletion.
Icon: schnelle Postfach- und Nutzersuche

Full-Text Search

Find any email fast, even in large archives.
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Storage Optimization

De-duplication and compression reduce storage requirements.
Security lock icon

Access Controls

Granular user and permission management for security and data protection.
Cloud upload icon

Audit-Proof Storage

Tamper-proof, encrypted storage prevents subsequent changes and ensures audit-proof integrity.
Funktions-Icon Journaling

Journaling

Complete capture of every inbound and outbound email - even messages deleted later remain fully archived.
Funktions-Icon Legal Hold

Legal Hold

Extend retention on demand: protect relevant emails from deletion for litigation and legal cases.

Supported Email Systems

Managed MailStore archives email from almost any environment - whether cloud, your own server, or a classic provider. We handle the setup for you.

Microsoft 365
Microsoft Exchange
Google Workspace
IMAP & POP3
PST files
MDaemon, IceWarp, Kerio & many more

Why Email Archiving Is Mandatory

Companies in Germany must retain business-relevant emails completely, unaltered and for several years. Managed MailStore provides the technical foundation for this.

GoBD requirements supported

The GoBD require complete, immutable and traceable retention of tax-relevant emails. MailStore archives without gaps, logs every access and is certified to IDW PS 880 - the certificate confirms that the software enables GoBD-compliant archiving.

Meet Retention Periods

Depending on the document, retention periods of 6 to 10 years apply (German HGB & AO). Retention policies ensure nothing is deleted too early or forgotten.

Stored audit-proof, operated in Germany

Encrypted, immutable storage in ISO 27001 certified data centers in Germany - data processing agreement under Art. 28 GDPR included.

General information - not legal or tax advice. Your tax advisor can clarify which retention periods apply to you.

Common misconception

An archive is not a backup - and a backup does not replace an archive

Both sound like "emails are safe", but they solve entirely different problems. Backups alone are not designed to meet legal retention requirements.

Backup

Recovery
Purpose: restore systems after failure or attack
Snapshot - continuously overwritten
Deleted emails are gone once retention expires
Finding a single old email? Tedious to impossible

Archive

Retention
Purpose: meet legal retention obligations (GoBD)
Every email is stored immutably on send/receive
Stays intact - even if deleted from the mailbox
Full-text search across years, in seconds
In short: the backup saves your operations, the archive delivers the emails you need in seconds during a tax audit. We provide both - email archiving with MailStore and Backup as a Service from a single source.

A Solution Without Compromise

A Full-Featured Archive for Every Client

Your data is never stored alongside other companies' data in a shared archive. Instead, every client gets a dedicated archive instance that runs entirely separately.

Illustration: separate, protected email archives for each customer

Long-Term Independence

Managed MailStore is not a one-way street. All emails can be restored from the archive at any time and in standard formats. This guarantees long-term independence - even from Managed MailStore itself.

Illustration: export emails in standard formats at any time

Confidentiality of Your Data

We operate your archive instance. We only access content when you instruct us to - for example in a support case. Your data is stored encrypted, and every access is logged.

Illustration: encrypted emails with logged access

Convenient, Fast Access

Your team can access archived emails through seamless Microsoft Outlook integration, via Web Access, or on mobile - and retrieve them in seconds.

Illustration: fast access to archived emails via laptop, smartphone and browser

Up and Running in 3 Steps

From the first consultation to a fully running archive, we handle the setup for you - including the import of your existing emails up to 25 GB.

1

Consultation & Analysis

Together, we assess your number of mailboxes, email system and your requirements for retention and access.

2

Setup & Migration

We set up your dedicated archive instance to your specifications (connection, journaling, retention rules), import existing emails - including PST files and legacy mailboxes - and hand the archive administrator over to you.

3

Automatic Operation

From then on, all emails are archived automatically and audit-proof - accessible via Outlook, web browser or mobile. We operate the instance, backups and updates - you manage your archive settings yourself or commission us.

FAQ

Frequently asked questions

What is email archiving?
With email archiving, all incoming and outgoing emails are automatically stored in full and in an unalterable form in a central, secure location, separate from the mailbox. This ensures long-term access and audit-proof retention, even if emails are deleted from the mailbox.
How does email archiving work with Managed MailStore?
Managed MailStore is connected to your email system (e.g. Microsoft 365 or Exchange) and automatically archives incoming and outgoing emails in an exclusive instance for you in German data centers. Your employees can continue to access all emails via Outlook, a web browser, or mobile devices.
Is email archiving mandatory for my company?
As a rule, yes: under German commercial and tax law (HGB, AO, GoBD), business and tax-relevant emails must be retained for 6 to 10 years depending on the document - this also applies to small businesses and sole proprietors. The law does not prescribe specific software, but an email archive is the practical way to retain emails completely, unaltered and searchable. Your tax advisor can clarify which obligations apply in your case.
What is the difference between archiving and a backup?
A backup is used for short-term recovery in case of emergencies. An archive preserves emails in an unalterable, complete and audit-proof way over many years. Both complement each other - a backup does not replace email archiving.
Which email systems are supported?
Supported systems include Microsoft 365, Microsoft Exchange, Google Workspace, IMAP and POP3 mailboxes, as well as PST files. We handle the complete setup and integration for you.
Where is my data stored?
Exclusively in German data centers - encrypted and stored in a dedicated archive instance operated separately from other customers.
Does oneCorp have access to my emails?
Only when you instruct us to - for example in a support case. We operate your archive instance; the archive is managed by your archive administrator. Your data is stored in encrypted form, and every access is logged.
How much storage do I get?
50 GB per mailbox in a shared pool - so 500 GB for 10 mailboxes. We measure the archive size after de-duplication; MailStore compresses and de-duplicates, so 10 GB of mailbox typically takes up 4-6 GB of archive. If the pool is not enough, we expand it automatically in 100 GB steps for €4.99/month.
Can I export my data later?
Yes, at any time. All emails can be exported from the archive in standard formats, ensuring your long-term independence.
How much does Managed MailStore cost?
From €3.99 per mailbox per month - including 50 GB archive storage, archive administrator and operation. Minimum billing 3 mailboxes, term 12 or 24 months.
Can I create an audit user?
Yes. Audit users get read-only access for auditing, data protection or compliance. They need their own licence but use no storage: €2.99 per user per month.
Do I need my own administrator?
Yes - and it is included in the price. Every instance has an archive administrator with which you manage users, retention rules and access rights yourself. Additional administrators can be booked for €2.99 per user per month. On request, we take over administration for €29 per month.
How are shared and functional mailboxes billed?
Like a regular mailbox. Every archived mailbox is a licensed user.
What happens to the mailbox of an employee who has left?
The user is removed, the licence becomes free and billing ends at the end of the month. The archive remains audit-proof and searchable.
Who is responsible for GoBD and GDPR compliance?
oneCorp provides and operates the archiving platform: instance, data backup, updates, availability, data center in Germany. Decisions on retention periods, deletion rules, journaling, legal hold and access rights, as well as the procedural documentation, remain with you as the operator of the archive. Whether the archiving meets the commercial, tax and data protection requirements that apply to you is your responsibility to verify - if necessary with your tax advisor or legal counsel. On request, we provide the technical description of your instance for your procedural documentation (system documentation, €149).
What does setup cost?
Nothing with a 24-month term. With a 12-month term, €99 one-off - until 31 Dec 2026 we include setup and the import of your existing emails up to 100 GB free of charge. We import larger volumes for €0.79 per GB.

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