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Sovereign Mail & Groupware Server

Your own groupware. Free up to 6 mailboxes.

Mail, calendar, contacts, files and archive in one server. Beyond that from €2.40 per mailbox per year. Outlook, iPhone and Android work as usual.

Download for free Calculate your cost in 10 seconds
  • ~40 MB RAMIdle VmRSS incl. Webmail, Calendar & Contacts
  • from €2.40Business per mailbox/year · free up to 6 mailboxes
  • GoBD & Dual-DKIMS3 Object Lock, RSA + Ed25519 & ZUGFeRD
Technical summary (v1.0.0)

v1.0.0 · Enterprise Mail, Groupware, Webmail & GoBD. The modern enterprise mail server. Mail, Calendar, Contacts & GoBD 100% on your own server.

nextxch unifies ESMTP, IMAP4rev2, POP3, JMAP, CalDAV/CardDAV, Mobile Push (WBXML), Webmail PWA with calendar & contacts, CLI/API, and GoBD WORM archiving inside one lean platform. Deploy as a native Windows® Service (.msi), Linux® daemon, or Docker® Compose · free up to 6 mailboxes, Business from €2.40, Enterprise with ActiveSync®, EWS and MAPI from €4.80 per mailbox per year, powered by .NET 11. Send confidential files straight from webmail with Encrypted File Share: AES-256 encrypted, password-protected, with expiry and access log.

nextxch webmail with inbox, phishing protection and calendarnextxch webmail with inbox, phishing protection and calendar
Live demo Try the webmail Inbox, phishing protection, calendar. Right in your browser. Try now Live demo Try the admin cockpit Domains, spam protection, GoBD archive and live operations. Try now

Compatible with Microsoft Outlook · iPhone · Android · Thunderbird · Apple Mail

Full data sovereignty · no US CLOUD Act: All mail, calendars, contacts and private keys stay 100% on your own infrastructure in Germany, the EU or your own data center.

Made and hosted in Germany Made and hosted in Germany exali IT-Haftpflicht Siegel iqmeta GmbH IT Liability InsuredVerified Seal · iqmeta GmbH

Real interfaces at a glance

Admin cockpit, GoBD archive and webmail app.

Webmail
nextxch webmail with inbox, phishing protection and calendarnextxch webmail with inbox, phishing protection and calendar

nextxch Webmail PWA: Fast inbox with hierarchical subfolders, labels, priorities, ZUGFeRD view, Rich-Text composer, and forensic Court/Archive PDF with full headers.

Try the webmail live Try the admin live
All screenshots with explanations

How it works. One sentence per step.Core architecture: one server instead of seven services.

No data center needed: a rented server for a few euros a month is enough to start.Mail server, spam filter, virus scanner, groupware, archive, file storage and webmail in one binary.

Your server A rented server or your own hardware. nextxch is installed in minutes.
nextxch Mail, calendar, contacts, files and archive. Spam and virus protection included.
Your devices Outlook, iPhone, Android and browsers connect automatically.
Host Windows service, deb/systemd, launchd, container or Kubernetes. SQLite, PostgreSQL or SQL Server.
nextxch SMTP, IMAP, JMAP, DAV, ActiveSync, EWS, MAPI. Spam and virus filters, Sieve, GoBD archive.
Clients Autodiscover, Autoconfig and SRV set up Outlook, mobile devices and Thunderbird by themselves.
1 programInstead of running Exchange, spam filter, archive and file storage separately.
2nd siteOptional: if a server or provider fails, the second one takes over automatically.
CertificatesHTTPS and mail encryption set themselves up and renew automatically.
ACME + SNILet's Encrypt in one click, certificates are swapped without a restart.
ClusterCoordination via PostgreSQL (LISTEN/NOTIFY, advisory locks), mail optionally in S3.
OTLPPrometheus metrics, OpenTelemetry, structured logs and alerts via webhook.

Six reasons for nextxchEverything essential on board, in one binary

All 40+ features and benchmarks
More in operations: protocol logs, phishing protection, sessions and Encrypted File Share

Protocol Logs & Statistics

Persistent logs like hMailServer (inbound and outbound SMTP dialogue, IMAP, ActiveSync, logins) with live viewer, delisting report and statistics per account, domain and server.

Phishing Protection & Self-Service Unblock

Brand and link heuristics, "check for phishing" in webmail, detection of 69 sending services, and unblock requests with automatic PTR, MX and SPF checks.

Sessions, Auto-Logout & IP Countries

Login history across all protocols, sign out per device or everywhere, idle auto-logout and a country flag next to every IP address (offline via DB-IP Lite).

New in Webmail

Encrypted File Share · Confidential and Secure Transfer

Send large files up to 50 MB straight from Webmail: AES-256-GCM encrypted, password protected, a personal link per recipient, download limits, expiry, and a complete audit trail (opened and downloaded with timestamp and IP) including a forensic PDF certificate. Upload request links let external partners send files to you just as securely.

Explore Encrypted File Share

Outlook stays

Outlook for Windows and Mac, iPhone and Android connect as they do with Exchange. Calendar, contacts, tasks, delegation and public folders work as usual. No retraining. Outlook with an Exchange account and ActiveSync on phones need Enterprise or the 30-day trial.

All features

Your data

No dependency on someone else's cloud. You decide where your mail lives. Mailboxes can additionally be encrypted with the user's own key (from Business).

Security and trust

Fair cost

Business from 7 mailboxes, Enterprise with the Outlook protocols from 15. The more mailboxes, the lower the price. Free up to 6 mailboxes. Add hosting: your own or a rented server. The cluster calculator shows the total cost.

Open the cluster calculator

GoBD archive built in

Immutable storage (WORM), procedural documentation, auditor role and full-text search, including attachments and ZUGFeRD invoices. Included from Business.

All features

Webmail like an app

Installable as an app, with booking pages, Encrypted File Share, Teams meetings, voting buttons and Outlook-style keyboard shortcuts. Booking pages, Encrypted File Share and Teams meetings come with Business.

Open the live demo

1-click migration

Wizards for Exchange 2013 to 2019, hMailServer, IMAP and Outlook PST files. Mailboxes, calendars and contacts move along. Migration from Exchange and PST import are part of Enterprise.

Migration guide

Streaming and dual-stack IPv6

Mail is streamed instead of loaded into memory in full. Every service listens on IPv4 and IPv6. SMTP, IMAP4rev2, POP3, ManageSieve, JMAP, CalDAV, CardDAV, WebDAV, ActiveSync, EWS and MAPI in one binary.

Streaming & Dual-Stack IPv6 (~40 MB RAM): ESMTP (CHUNKING), IMAP4rev2 (< 5 ms IDLE) & JMAP on true dual-stack sockets ([::]) with Happy-Eyeballs MX and IPv6 /64 greylisting.

Supported protocols

Webmail, calendar and contacts

Installable web app with calendar, contacts, tasks, notes and files. Sync via CalDAV, CardDAV, JMAP and Web Push.

Webmail, Calendar & Contacts: Built-in Webmail PWA with Month/Week/Day calendar, People cards, CalDAV/CardDAV, Mobile Push (WBXML), and messenger-safe iPhone setup.

Open the live demo

Deliverability and dual-key DKIM

Dual DKIM with RSA-2048 and Ed25519, DMARC and TLS-RPT reports, MTA-STS, DANE/TLSA, one-click ACME and the DNS advisor. Plus SpamGuard, ClamAV, Pyzor, AI spam filter (from Business) and Fail2Ban.

10/10 Deliverability & Dual-Key DKIM: Parallel RSA-2048 & Ed25519 keys with instant mode switching, SPF, DMARC, ARC, Let's Encrypt ACME (0 ms SNI), MTA-STS, DANE & SpamGuard.

Deliverability

GoBD WORM, ZUGFeRD and OCR

Archive with a WORM lock, optionally on S3 with Object Lock. Full-text and OCR search, ZUGFeRD invoices are recognised. Procedural documentation per GoBD. Included from Business.

GoBD WORM, ZUGFeRD & OCR Search: Immutable S3 Object Lock (COMPLIANCE), Legal Hold, read-only Auditor role, plus full-text indexing across PDFs, ZUGFeRD XML, and OCR scans.

All features

Scoped API keys, CLI and OpenTelemetry

Public REST API with OpenAPI schema, scoped API keys, signed webhooks, transactional send API, SCIM 2.0, OpenID Connect, nextxch-cli, Prometheus and OTLP. Included from Business.

Scoped API Keys, CLI & OpenTelemetry: Scoped smk_ keys with RBAC & CIDR allowlists, declarative nextxch-cli (JSON snapshots & IaC apply), OTLP tracing, and live Message Trace.

CLI and API

Windows .msi, SQL Server and 1-click migration

Real Windows service via MSI, deb package with systemd, launchd, container image and Kubernetes. SQLite, PostgreSQL or Microsoft SQL Server. Migration from Exchange, hMailServer, IMAP and PST (Exchange and PST with Enterprise).

Windows .msi, SQL Server & 1-Click Migration: Native Windows Service without Docker, choice of SQLite WAL, MS SQL Server (2019-2025) or PostgreSQL 18, plus 1-click hMailServer & IMAP import.

Ways to install
Quick start

Productive in 60 seconds

Guided installationWizard for Windows, Linux and Docker. 8-step installation guideFrom DNS to the first mailbox. 19 hoster and NAS blueprintsHetzner, netcup, Synology and more.

What does nextxch cost?

Free up to 6 mailboxes. Beyond that you pay a licence per mailbox and year. The more mailboxes, the cheaper each one.

Add hosting: your own server or a rented one, for example Hetzner Cloud from €5.99 net per month (as of 11/2026).

Total cost with hosting and high availability in the cluster calculator
Business · licence €36 per year €2.40 per mailbox
About €310 a year less than the average of other groupware licences Average of 6 groupware offers with a public euro price (€23.08 per mailbox and year), details on the comparison page.

Free, Business and Enterprise

Free€0up to 6 mailboxes, forever Businessfrom €2.40from 7 mailboxes, down to €1.50 by volume Enterprisefrom €4.80from 15, with Outlook, ActiveSync, EWS, MAPI

Licence prices net per mailbox and year. Hosting comes on top. Volume steps and tier comparison

Deep dives and live tools

Comparison, licence calculator, DNS checker and manual.

System and cost comparisonAgainst Stalwart, Exchange Online, hMailServer and more.
  • All-in-One: Built-in Webmail PWA, CalDAV/CardDAV & ZUGFeRD with zero extra services, ActiveSync® with Enterprise
  • Windows & Linux: Native .msi service, MS SQL Server, PostgreSQL 18 & Docker
  • Fair TCO: Enterprise with ActiveSync®, EWS and MAPI from €4.80 per mailbox per year vs. ~€23.08 on average for other groupware offers
Licence calculatorVolume prices for your mailbox count.
  • Three clear tiers: Free with webmail and all base protocols, Business with GoBD archive, tenants and API, Enterprise with ActiveSync®, EWS and MAPI
  • Volume pricing: lower from 100, 250 and 1,000 mailboxes, the step price applies to all mailboxes; billed yearly in advance
  • B2B Checkout: Instant ordering via SEPA invoice transfer or card
Cluster calculatorServers, high availability and total cost across several providers.DNS checkerCheck MX, SPF, DKIM, DMARC, MTA-STS and DANE live.
  • Live Inspector: Audits MX, SPF lookup limits, Dual-DKIM, DMARC, MTA-STS & DANE
  • PTR Generator: Builds exact IPv4 & 32-nibble IPv6 reverse DNS entries
  • Pitfall Detection: Flags wildcard DNS collisions (*.domain) and missing FCrDNS
DeliverabilityWhat Gmail, Microsoft 365 and T-Online check technically.Protocols and standardsSupported RFCs and security mechanisms.ManualInstallation, operations and every module.
  • Documentation Hub & 19 Blueprints: 14 structured guides with instant Ctrl+K search
  • Step-by-Step: Guided 8-step installation from fresh host to verified mail flow
  • Focused Guides: pfSense/OPNsense, Dual-Stack IPv6, SpamGuard, CLI/API & GoBD
  • 19 Environments: Hetzner, netcup, IONOS, Proxmox, Synology, Docker & Windows
All 40+ featuresWith benchmarks and details.

Frequently asked questions

What counts as a mailbox?

Only active user mailboxes. Aliases, distribution lists, rooms and resources do not count.

Do I need Enterprise for Outlook?

For Outlook with an Exchange account (MAPI, EWS) and ActiveSync on phones, yes. IMAP, CalDAV and CardDAV work in every tier.

What happens after the 30-day trial?

Without an Enterprise key, ActiveSync, EWS and MAPI are locked again. Mail, calendars and everything else keep running. The trial and Enterprise are available on request.

What comes on top of the licence?

Hosting: your own server or a rented one. The cluster calculator shows the total cost, also with a second site.

What does nextxch cost?

Free stays free forever for up to 6 mailboxes. Business costs €2.40 per mailbox per year from 7 mailboxes (minimum €16.80), Enterprise with ActiveSync®, EWS, MAPI over HTTP and Autodiscover costs €4.80 from 15 mailboxes per server (minimum €72.00), on request with a separate licence agreement for the Microsoft protocols. The price drops in steps from 100, 250 and 1,000 mailboxes. Billed yearly in advance, all prices net excluding VAT.

How does volume pricing work?

Once a threshold is reached, the step price applies to all mailboxes of the licence. Business example: 10 mailboxes cost €24.00 per year, 250 mailboxes cost €1.80 each, €450.00 per year in total.

Why are ActiveSync®, EWS and MAPI only in Enterprise?

Because of Microsoft®'s licence terms for these protocols, nextxch unlocks ActiveSync®, EWS, MAPI over HTTP and Autodiscover only with a signed Enterprise or 30-day trial key. Without that key, Outlook® works via IMAP/SMTP plus CalDAV/CardDAV, and phones via IMAP, CalDAV and CardDAV.

How do I get the free Enterprise trial?

On request: with the request form at nextxch.com/contact/ or in the admin cockpit (/admin/, licence page, request an Enterprise trial). A separate licence agreement for the Microsoft protocols is signed with the first request; we get back to you within 1 business day with the contract and key. The trial key unlocks every feature for 30 days, including the Microsoft protocols, and then expires automatically. The server then falls back to Free or the purchased tier without data loss.

How does nextxch compare on price with other solutions?

The calculator compares against the average of 6 groupware offers with a public euro price (€23.08 per mailbox per year). nextxch Business costs from €2.40, €1.80 from 250 mailboxes, and includes a built-in webmail with complete groupware; Business adds sharing, delegation, rooms, booking pages, Teams meetings and the GoBD archive. The comparison page shows the detailed comparison with individual solutions, with prices and sources.

Is the licence added on top of the free mailboxes?

No. The licence covers the total number of active mailboxes. If you use 7 or more mailboxes, you license all of them, for example 10 Business mailboxes for €24.00 per year.

From when is a binding SLA included?

Up to 9,999 mailboxes include standard engineering email support. Starting at 10,000 licensed mailboxes, a binding Enterprise SLA with guaranteed response times directly from iqmeta GmbH in Germany and a Source-Code Escrow schedule are included at no extra charge (available below as an optional paid addendum).

What happens if my mailbox count grows mid-cycle or if I cancel?

Existing mail flow is never interrupted. You can add mailboxes at any time. A purchased key is valid for 12 months; the annual licence then ends, the annual subscription renews unless cancelled with 30 days' notice to the end of the term. The server then cleanly reverts to Free, existing mailboxes keep working and no data is lost.

Run nextxch on your own infrastructure.

Windows, Linux, macOS, Docker or Kubernetes. Free up to 6 mailboxes.

Start immediately with Free (up to 6 mailboxes, free forever) or request the 30-day Enterprise trial: it unlocks everything, including ActiveSync®, EWS and MAPI over HTTP.

Get started