GMX Mail vs Soverin

Compare GMX Mail and Soverin on capabilities, jurisdiction, assurance, and fit for European buyers.

Both listed as alternatives to: Gmail, Outlook.com

GMX Mail

Germany· Email Services

Needs review

Shortlist GMX Mail for consumer or light-professional freemail when you want a German United Internet operator, claimed German mailbox data centers, large free storage, and standard IMAP/POP—with optional OpenPGP. Skip when you need zero-access encryption by default, enterprise DPA/audit packs, or an ad-free architecture as the baseline; consider Proton Mail instead.

German operatorMailbox in DE (claimed)IMAP / POP3 / SMTPOptional OpenPGPFree ad-supportedSaaS only

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Soverin

Netherlands· Email Services

Needs review

Shortlist Soverin when you want Dutch-operated, paid IMAP email with custom domains, unlimited aliases, and strong mail-auth standards without Google/Microsoft ads. Skip when you need zero-knowledge E2EE—consider Proton Mail or Tuta instead—or a full productivity suite (mailbox.org / Microsoft 365).

NL / EU operatedCustom domainsIMAP / CalDAVNo ads / no trackingISO 27001 (claimed)DANE / DNSSEC

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Highlighted rows differ between the two products.

GMX Mail vs Soverin: Snapshot
Feature	GMX Mail	Soverin
Country of origin	Germany	Netherlands
Category	Email Services	Email Services
Open source	No	No
Self-hosted	No	No
Headquarters	Germany	Netherlands
Legal entity	1&1 Mail & Media GmbH (Zweigniederlassung Karlsruhe; Hauptsitz Montabaur)	Soverin B.V. (Amsterdam); owned by The Sharing Group / TSG Online (Dutch) as of September 2025 acquisition announcement
Governing law	German law (international T&Cs); GDPR applies as EU controller	Not listed
US parent / control	No known US parent	No known US parent
CLOUD Act exposure (indicative)	Medium	Low
Hosting / residency	Vendor privacy (EN): FreeMail emails, address book, and calendar processed in secure data centers in Germany. Product security pages: European data centers for stored mail. Group United Internet AG (DE). Named non-mail paths: Google Analytics/GTM on portal; Google/Yahoo search partnership; international ad partners under consent; DE privacy allows third-country transfers with Chapter V safeguards when used. No public exhaustive mail-infra subprocessor list found.	Vendor: EU-only processing; data in NL; self-operated Dutch DCs, no hyperscaler. TechRadar: 3 NL DCs. Core mail hosts on Soverin B.V. AS211993. External first-line support partner under DPA/NDA (country unpublished). HIBP k-anon password checks; Let’s Encrypt; domain DNSSEC partner. No AWS/GCP/Azure as primary mailbox hosts in public materials.
Summary	German FreeMail from 1&1 Mail & Media GmbH (United Internet): large free storage, IMAP/POP/SMTP, optional OpenPGP and 2FA, ad-supported consumer webmail.	Dutch privacy-first email hosting: custom domains, open IMAP/SMTP/CalDAV, 25 GB mailboxes, no ads or content scanning, servers operated in the Netherlands.
Tags	imap freemail webmail germany openpgp united-internet ad-supported consumer	imap privacy email gdpr netherlands custom-domain saas

At a glance: GMX Mail vs Soverin
At a glance	GMX Mail	Soverin
HQ / entity	1&1 Mail & Media GmbH, Montabaur (DE)	Not listed
Parent group	United Internet AG (DE)	Not listed
Product type	Consumer FreeMail + optional paid tiers	Not listed
Hosting (claimed)	Mailbox/calendar data in German data centers	Not listed
Protocols	Webmail; POP3/IMAP/SMTP (opt-in)	IMAP, SMTP, CalDAV, CardDAV
Open source	No	Not listed
Self-hosted	No	Not listed
HQ	Not listed	Amsterdam, Netherlands (Soverin B.V.)
Group	Not listed	The Sharing Group / TSG Online (acq. Sep 2025)
Hosting	Not listed	Dutch data centres; vendor claims self-operated, no hyperscaler
Storage	Not listed	25 GB per mailbox (vendor-stated)
Self-host / OSS	Not listed	No / No
Commercial model	Not listed	Annual prepaid; 30-day mailbox money-back; no free tier

Key capabilities: GMX Mail vs Soverin
Key capabilities	GMX Mail	Soverin
German operator	Yes	Not listed
Mailbox in DE (claimed)	Yes	Not listed
IMAP / POP3 / SMTP	Yes	Not listed
Optional OpenPGP	Yes	Not listed
Free ad-supported	Yes	Not listed
SaaS only	Yes	Not listed
NL / EU operated	Not listed	Yes
Custom domains	Not listed	Yes
IMAP / CalDAV	Not listed	Yes
No ads / no tracking	Not listed	Yes
ISO 27001 (claimed)	Not listed	Yes
DANE / DNSSEC	Not listed	Yes

GMX Mail

Large free mailbox storage with open protocols
gmx.com free accounts advertise up to 65 GB email storage and 50 MB attachments. POP3, IMAP, and SMTP are supported after you enable them in settings (TLS 1.2+; imap.gmx.com / mail.gmx.com). Suits users who want client choice (Thunderbird, Outlook, mobile) without Google or Microsoft as the mailbox host.
Optional OpenPGP end-to-end encryption (Mailvelope)
GMX offers free OpenPGP messaging via the Mailvelope browser extension: key generation, local key storage, key directory, and mobile recovery. Encryption is opt-in per message after setup—not whole-mailbox zero-access by default. Best for occasional sensitive threads when both parties can use OpenPGP.
Aliases, Mail Collector, and multi-account inbox
Create up to 10 alias addresses (including other GMX domains) managed in one inbox, and pull up to 10 external accounts via Mail Collector. Useful for freelancers and project mail without juggling multiple passwords or providers day-to-day.
Spam filtering, antivirus, and optional TOTP 2FA
Free accounts include automated spam filtering (user blacklist and optional improved detection) and antivirus scanning of mail and cloud files. Optional two-factor authentication uses an authenticator app (TOTP); third-party clients use app-specific passwords when 2FA is on.
Bundled Cloud, calendar, contacts, and Online Office
Accounts include contacts, calendar/organizer, about 2 GB GMX Cloud with share links, and Online Office for common document formats—enough for light personal productivity without a separate suite subscription.

Soverin

Custom domains with unlimited aliases
Host mail on your own domain (bring existing or register through Soverin). Unlimited aliases—plus-addressing or domain names—deliver into one mailbox, plus optional random @sinenomine.email private aliases that hide the real address. Suits freelancers and SMEs who need brandable addresses without per-alias fees.
Open IMAP/SMTP plus CalDAV/CardDAV
Use any standards-based client or device for mail, calendar, and contacts—no proprietary app required. Dashboard import helps migrate from other providers. Ideal when IT wants Thunderbird, Apple Mail, or Outlook without locking into a closed webmail ecosystem; not a zero-knowledge E2EE product by default.
Mail-path security: DANE, DKIM, DMARC, IP stripping
Outbound and inbound paths use TLS; Soverin publishes and honours DANE/TLSA, signs with DKIM, publishes SPF/DMARC, enables DNSSEC on managed domains, and strips personal IP addresses from outbound headers. 2FA is available and can be admin-mandated. Buyers still need their own OpenPGP setup for end-to-end content secrecy with external parties.
25 GB mailboxes with per-user encrypted backups
Each mailbox includes a stated 25 GB quota covering mail, calendar, and contacts. Nightly backups use individually generated keys; Soverin states that emptying trash permanently deletes data and that leaving the service removes backups when the key is destroyed. Extra mailboxes can share storage for small teams.
Multi-mailbox and channel-friendly business use
Purchase and assign additional mailboxes on a domain, with admin tooling for teams. Soverin markets to hosters, ISPs, MSPs, and independent professionals for multi-mailbox and white-label scenarios—useful when you want Dutch-operated email without building your own mail stack.

Assurance & compliance: GMX Mail vs Soverin
Assurance & compliance	GMX Mail	Soverin
Independent security / no-logs audit	Not found OpenPGP/Mailvelope path described as externally reviewed; no public independent no-logs audit for FreeMail mailbox access found on product pages.	Not found No public third-party no-logs or full security audit PDF located; privacy claims are first-party.
ISO 27001	Not found No GMX FreeMail-branded ISO 27001 certificate located on security/privacy pages in this research pass (group companies may hold certs under other brands).	Vendor claimed Vendor states independently audited ISO 27001; certificates available on request via support@soverin.net. Not re-verified against a public registry entry in this pass.
SOC 2 / SOC 3	Not found No SOC 2/3 report found on GMX public security pages.	Not found No SOC 2/3 claim found on primary pages reviewed.
GDPR / EU data protection	Vendor claimed EU/German controller; public privacy notices under GDPR; DPO published; supervisory authorities named (BfDI / LfDI RLP).	Vendor claimed NL entity; AVG-framed privacy statement; EU-only processing claimed; GDPR Proof messaging on recognitions page.
US CLOUD Act exposure (indicative)	Partial German entity and parent (United Internet AG); mailbox data claimed in German DCs. Partial/medium because portal analytics include Google LLC tools, freemail ads involve international partners, and no full public mail-infra subprocessor list. Not legal advice.	Partial EuropeanStack assessment: low exposure path—Dutch Soverin B.V., Dutch The Sharing Group owner, claimed self-operated NL hosting without public AWS/GCP/Azure mailbox hosts. Partial because residual subprocessors (support partner jurisdiction, domain partners, HIBP hash checks) need buyer confirmation. Not legal advice.
Data processing agreement (B2B)	Not found Product is primarily consumer FreeMail under GTCs/privacy policy; no public self-serve B2B DPA flow found for FreeMail shortlisting.	Vendor claimed Privacy statement states it qualifies as an Article 28 AVG processing agreement; other DPAs expressly rejected. Confirm signed annex for enterprise use.
EU AI Act	Not applicable Not an AI-centric product; optional assistive features may appear in product privacy text but FreeMail is not marketed as an AI system.	Not applicable Email hosting product; vendor emphasises no AI scanning/mining of mailbox content for ads.
ISO 9001 / ISO 14001	Not listed	Vendor claimed Vendor-claimed quality and environmental certifications; certificates on request.
NIS2 readiness	Not listed	Vendor claimed Vendor markets NIS2 Ready; buyer press also asserts NIS2 compliance—confirm evidence package.
NEN 7510 (healthcare NL)	Not listed	Partial Vendor states NEN 7510 certification is in progress, not completed.

Considerations & known limitations: GMX Mail vs Soverin
Considerations & known limitations	GMX Mail	Soverin
Advertising-funded free tier	Medium FreeMail depends on ads and (with consent) interest-based targeting and partner sharing. Privacy posture differs from paid privacy mail. Practical impact: expect consent UX, ad surfaces, and partner lists—not a zero-ads default.	Not listed
E2E encryption is optional, not default	Medium Without OpenPGP setup, mailbox content is accessible to the provider like conventional hosted mail. Practical impact: do not treat GMX FreeMail as zero-access encryption architecture.	Not listed
Incomplete public infrastructure subprocessors	Medium Residency for mail is claimed (Germany/EU), but there is no enterprise-style published subprocessor inventory for core mail infrastructure. Portal paths name Google Analytics and global ad partners. Practical impact: extra questionnaire work for high-assurance buyers.	Not listed
Inactivity and freemail operational policies	Low Terms/privacy allow deletion of free mailbox content after prolonged inactivity (about 180 days without login on FreeMail privacy text). Practical impact: inactive project addresses can disappear if not maintained.	Not listed
No public ISO/SOC package for FreeMail	Low Security pages emphasize product features (spam, AV, 2FA, PGP) rather than downloadable ISO/SOC evidence for FreeMail. Practical impact: may fail enterprise vendor security questionnaires without further vendor dialogue.	Not listed
Not zero-knowledge E2EE by default	Not listed	Medium Unlike Proton/Tuta, Soverin is a classic IMAP host. Provider infrastructure can process content for delivery and spam filtering. Practical impact: unsuitable as a drop-in for policies that require provider-blind encryption without extra client crypto.
Unnamed external support partner	Not listed	Medium Privacy statement discloses a first-line support partner with limited account data under DPA/NDA, but does not publish the partner name or country. Practical impact: add an open diligence item for any regulated workload.
ISO certificates not self-serve public	Not listed	Low ISO 27001/9001/14001 are claimed with certificates via support rather than a public PDF registry link found in research. Practical impact: procurement should request current attestations before treating certs as verified.
2025 group acquisition	Not listed	Low The Sharing Group acquisition may change subprocessors, tooling, or brand packaging over time even if continuity is promised. Practical impact: re-check DPA and hosting annex annually.
Email-centric support	Not listed	Low Public materials emphasise human Dutch-team email support; TechRadar notes no live chat or phone. Practical impact: large orgs needing 24/7 phone SLAs may find coverage thin.

Fit

GMX Mail

Best fit when

Individuals and freelancers who want a European freemail address with large free storage and IMAP client freedom
Users consolidating multiple addresses via aliases (up to 10) and Mail Collector
Buyers who prefer a German legal controller (1&1 Mail & Media GmbH / United Internet) over US Big Tech freemail
Teams that only need optional OpenPGP for specific sensitive threads, not zero-access by default
Users already familiar with GMX/WEB.DE in German-speaking markets who need international domains (e.g. gmx.com)

Poor fit when

Organizations that require default end-to-end / zero-access encryption for all mail
Procurement that needs a published independent security audit pack, ISO/SOC evidence, and a B2B DPA as standard shortlist inputs
Teams that cannot accept advertising-funded freemail economics or interest-based ad consent UX
Custom-domain corporate mail and admin controls at Microsoft 365 / Google Workspace depth
Self-hosted or open-source mail stack requirements

Consider instead when

When: You need zero-access encryption by default and a privacy-first paid model without ad-funded freemail as the core product
Consider: Proton Mail
Proton is the stronger shortlist peer in this catalog for E2E-first evaluation.
When: You need Google Workspace-class collaboration and are willing to accept US Big Tech jurisdiction
Consider: Gmail / Google Workspace
Richer suite integration; different sovereignty and ad/ecosystem tradeoffs.
When: You need Microsoft ecosystem mail, calendar, and compliance tooling
Consider: Outlook.com / Microsoft 365
Strong enterprise admin story; US parent and CLOUD Act path differ from GMX.

Soverin

Best fit when

Individuals and freelancers who want a paid European mailbox on their own domain with any standard mail client
SMEs needing several mailboxes, aliases, and CalDAV/CardDAV without adopting Google Workspace or Microsoft 365
Teams prioritising Dutch jurisdiction and claimed no-hyperscaler hosting over zero-knowledge E2EE
Hosters/ISPs/MSPs evaluating white-label or multi-mailbox Dutch email
Buyers who value DANE, DKIM/DMARC, DNSSEC, and IP-header stripping on an open-standards stack

Poor fit when

Organisations that require default zero-access / E2EE mail against the provider (use Proton Mail or Tuta)
Users seeking a free tier, anonymous cash-only signup, or purely self-hosted open-source mail servers
Enterprises needing SSO, eDiscovery archives, phone support SLAs, or a full office suite in one vendor
Workloads that depend on US-region mailbox hosting or hyperscale global PoPs

Consider instead when

When: You need zero-knowledge E2EE and a privacy-first mobile/web ecosystem
Consider: Proton Mail or Tuta
Trade open IMAP convenience for stronger default content secrecy vs the provider.
When: You want German-hosted paid mail with broader office-style add-ons
Consider: mailbox.org or Posteo
Compare storage, admin features, and payment anonymity (Posteo) against Soverin’s domain/alias model.
When: You need Google- or Microsoft-class collaboration and global free consumer mail
Consider: Gmail or Microsoft 365 / Outlook.com
Different risk and advertising model; not EU-sovereignty substitutes.

Open questions for due diligence

GMX Mail

Will 1&1 Mail & Media sign a B2B DPA and publish a current mail-infrastructure subprocessor list for our use case?
Are FreeMail mailbox systems solely on United Internet / 1&1 operated German DCs, or are any US-group cloud providers used for primary storage, backup, or DR?
What independent audits or certifications (if any) cover the FreeMail platform beyond the Mailvelope/OpenPGP path?
For paid/premium mailboxes: which advertising and tracking paths remain, and what contractual residency language is available?

Soverin

What is the legal name and country of the first-line support partner, and is a current subprocessor list available under NDA?
Can Soverin provide the latest ISO 27001/9001/14001 certificates and scope statements without delay?
After The Sharing Group acquisition, are any new group companies (e.g. Mijndomein, Greenhost, Leafcloud tooling) in the mailbox data path?
Is NEN 7510 certification complete for healthcare use cases, or still in progress?
Which domain registrar(s) handle customer DNSSEC, and where are registry data stored?