S SignatureHub

GDPR-compliant · hosted in Germany

Central email signatures
for your whole organisation.

Consistent signatures, compliant disclaimers, marketing banners — managed centrally, attached automatically. Compatible with Postfix, Plesk and Microsoft 365.

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Features

  • Microsoft 365 connector with Entra ID sync (users, groups, photos, aliases)
  • SMTP relay connector for Postfix, Plesk and any MTA
  • Per-user SMTP credentials for companies without their own mail server — point the mail client straight at mx.signaturehub.de port 2587 (STARTTLS)
  • Drag-and-drop signature designer with multi-client preview
  • Rule engine: sender, recipient, internal/external, reply/forward, date, subject regex
  • Banner campaigns with GDPR-compliant click tracking
  • Policy tester for validating rules before going live
  • Self-service portal for employees (magic-link login, own master data, own SMTP credentials)
  • Reseller programme with consolidated invoicing

Three ways to connect

  1. Microsoft 365 / Exchange Online: outbound and inbound connector plus transport rule, smarthost mx.signaturehub.de on port 25 with TLS certificate authentication.
  2. Your own mail server (Postfix, Plesk, Exchange on-premises, sendmail): smarthost to mx.signaturehub.de:2587, STARTTLS with SMTP AUTH.
  3. No mail server at all: if your mailboxes are hosted with providers such as STRATO, IONOS, All-Inkl or 1&1, enter mx.signaturehub.de port 2587 with STARTTLS as the outgoing mail server directly in the mail client — Outlook, Apple Mail, iPhone, Android, Thunderbird. Every employee gets their own credentials, optionally one per device. Incoming mail stays with your current provider.

Pricing

All prices net, per billable mail user. Annual billing = monthly price × 10, so two months are free.

  • Free — 0 €, permanently, up to 3 users (signature carries a „sent with SignatureHub" note)
  • Starter — 1.02 €/user/month, up to 25 mail users
  • Standard — 1.62 €/user/month (1.45 € from 26, 1.35 € from 101 users), up to 200 mail users, Microsoft 365 connector, banner campaigns
  • Pro — 1.92 €/user/month (1.75 € from 26, 1.60 € from 101, 1.45 € from 251, 1.30 € from 501 users), unlimited mail users, 99.9 % uptime SLA

Lowest effective price: 0.85 €/user/month (Starter billed annually). 14-day free trial, no credit card, cancel any time.

Comparisons

Frequently asked questions

Does this work without our own mail server, with mailboxes hosted at STRATO or IONOS?
Yes. Every employee gets their own SMTP credentials and enters mx.signaturehub.de, port 2587, STARTTLS as the outgoing mail server in their mail client — Outlook, Apple Mail, iPhone, Android or Thunderbird. Incoming mail stays with the existing provider; only the sending path runs through SignatureHub. No mail server of your own and no Microsoft 365 subscription is required.
Does every employee have to change their mailbox password?
No. The mailbox password stays untouched. The SignatureHub credentials are additional and apply to the outgoing server only. You can issue one password per device and revoke a lost device individually without touching the others.
Could someone use these credentials to send as a different address?
No. Per-user credentials are bound to the addresses of that mail user — primary address plus aliases. The gateway checks both MAIL FROM and the From: header and rejects with 550 5.7.1 as soon as one of them does not match.
Which server and port do I enter?
For mail clients and for customer mail servers acting as smarthost: mx.signaturehub.de, port 2587, STARTTLS, with SMTP AUTH. For Microsoft 365: smarthost mx.signaturehub.de on port 25 with TLS certificate authentication.
Is mail content stored?
No. Mail is processed in memory only — attach signature, forward — and never persisted. Only metadata (message-id, tenant, rule, timestamp) enters the audit log; body, subject and recipient addresses do not.
How does GDPR compliance work?
EU hosting in Germany (dream-soft GmbH, Münster). DPA on request via datenschutz@dream-soft.de. TOM catalogue as an appendix. We act as an Art. 28 GDPR processor.
Does it work with Microsoft 365?
Yes. Outbound and inbound Exchange connectors plus a transport rule, set up via the one-click installer or manually via PowerShell. Entra ID sync for employees and groups, including proxyAddresses for aliases and employee photos.
Why is the signature missing from my Sent folder?
Because the mail client stores the copy in Sent before the mail reaches the server. The signature is added server-side: the recipient sees it, your own Sent folder does not. This applies to every server-side signature solution, including Exclaimer and CodeTwo.
What does SignatureHub cost?
Free is permanently free for up to 3 users. Starter is 1.02 € per user per month, Standard 1.62 €, Pro 1.92 € — all net, with volume tiers from 26 users upwards. Annual billing drops two months, so the lowest effective price is 0.85 € per user per month.
What happens if your server goes down?
Mails are queued by the sending MTA (Postfix and Exchange do this automatically) and delivered once we recover. No mail loss. Our SLA commitment: 99.9 % uptime on the Pro plan.
Can I become a reseller as an IT service provider?
Yes. We run a partner programme with a dedicated reseller portal and consolidated invoicing. Margins are agreed individually, depending on volume, region and service level. Ask for terms via the contact form.
Is SignatureHub available self-hosted?
No. SignatureHub is designed as a hosted cloud solution in Germany — that keeps security updates, DKIM key rotation and compliance in one pair of hands. For organisations with strict compliance requirements we offer a dedicated cloud instance on separate hardware in our data centre, on request.
How long does onboarding take?
Self-service signup about 5 minutes. DNS setup (SPF, DKIM) 15 to 30 minutes depending on the provider. Connector configuration and first template about 30 minutes. All in, a one-hour workshop.