StampFlow
Sovereign by design|See it live

Email Signatures
You Can Prove

Centrally managed, compliant signatures for Microsoft 365 and Exchange. Run it as SaaS, or deploy the entire platform inside your own walls. Either way: one signature, on every client, verifiable by anyone.

Re: Q3 partnership

Alex Morgan

Director of Partnerships

Signed in transit. Verifiable by any recipient.

Signatures worth sending

From clean executive to full campaign - designed once, applied to every mailbox, rendered correctly in every client.

Executive

To: board@northwind.example

Subject: Q3 results and outlook

Best regards,

N

Northwind

Capital Partners

Est. 1987

Sarah Al-Otaibi

Chief Financial Officer

T+966 11 555 0143Es.alotaibi@northwind.exampleAKing Fahd Road, Riyadh 12212

Licensed by CMA. This message is confidential and intended solely for the addressee.

Card

To: partners@lumina.example

Subject: Design system handoff

Best regards,

OA

Omar Aziz

Head of Product Design

Lumina Studio

lumina.example

+971 4 555 0122 · Dubai Design District

inBeig
🏆Red Dot Design Award 2026 - Brand Identity
Campaign

To: clients@meridian.example

Subject: Your cloud migration plan

Best regards,

M

Maria Santos

Enterprise Sales · Meridian Cloud

m.santos@meridian.example|+34 91 555 0177

Live event

Meet us at GITEX 2026

Hall 4, Stand B-22 · 13-17 Oct · Dubai

Book a slot →
inXYT

Scheduled 01-15 Oct · variant B · 4.1% CTR

0

email bodies ever stored

AES-256

per-tenant encryption, keys you can rotate

1

signature on every client, never two

Watch your mail flow. Live.

This is the real dashboard - not a mockup. Every capability you enable appears on the diagram the moment it is on.

portal.yourcompany.com/mail-flow
StampFlow mail-flow dashboard showing a message being signed in transit

Built for Microsoft email

Deep, native integration with both worlds of Microsoft mail - cloud and on-premises.

Microsoft 365

  • Connectors and transport rules set up automatically
  • Signatures stamped in transit - every device, including mobile
  • Outlook add-in: preview, one-signature suppression, Sent Items updates
  • Directory sync keeps names, titles and photos current

Microsoft Exchange Server

  • On-premises Exchange, fully inside your network
  • Transport agent stamps on the server - nothing leaves your walls
  • Organization and OU-aware policies from your directory
  • The same portal, templates and audit as the cloud edition

Sovereign

Your signatures. Your infrastructure. Your choice.

Every other signature platform makes you send your mail through their cloud. StampFlow is the one that lets you keep everything inside your own walls, without giving up a single feature.

SaaS

Managed cloud

Connect Microsoft 365 in minutes. Connectors set themselves up, signatures apply in transit, nothing to install.

Self-hosted

Inside your walls

The full platform on your own VM - your data center, your sovereign cloud, even air-gapped. Built for government and regulated enterprises that cannot let mail leave.

No competitor offers this

MSP

Your brand on it

Run StampFlow as your own white-label signature service. Your name, your logo, your customers, your margin.

One signature. Everywhere.

Users with their own Outlook signatures send two - theirs and the company one. StampFlow silences the personal signature the moment they compose, and stamps the official one in transit.

  • Outlook classic, new Outlook, web, Mac and mobile - one toggle covers them all
  • No group policy scripts, no registry edits, no per-machine visits
  • Signed in transit, so it works from every device including phones

Always disable default Outlook signatures

Suppress personal signatures when users compose

Outlook for Windows and Mac: signature set to none

Outlook on the web and new Outlook: option disabled

Applied at the next compose, fleet-wide

BlocksFieldsImages
Name + Title block
Contact details row
Campaign banner slot

Design once. Deploy to thousands.

A visual designer with live preview, built for people who never want to see HTML - and a code view for those who do.

  • Directory-driven placeholders: names, titles, phones, photos - always current
  • Conditional blocks per department, language or campaign
  • Renders correctly in Outlook classic - the client that breaks everyone else’s HTML

Not just compliant. Provable.

Every stamped email carries cryptographic provenance. A recipient - or an auditor - can verify that a signature was really applied, by your organization, at that moment.

  • Public verification page for any stamped message
  • Tamper-evident audit trail of every policy and change
  • Data-loss prevention checks before mail ever leaves

Signature verified

Stamped by Your Company Ltd. Integrity check passed. Policy: Corporate signature v4.

Encrypted

Encryption even we cannot undo.

Every tenant’s data is encrypted under its own key. Not us, not a database administrator, not a stolen backup can read it. You can rotate the key yourself, from the portal, any time.

Per-tenant keys

AES-256-GCM, rotatable in one click

Nothing to leak

Email bodies are processed in memory, never stored

Standards-mapped

Designed against NCA ECC, ISO 27001 and GDPR controls

Penetration tested

Independently tested, findings closed and verified

Features

Everything a signature platform should be

Visual designer

Drag and drop blocks, live preview, ready-made templates, full code view when you want it

Signature policies

Who gets which signature, by group, department or organization - decided centrally

One signature everywhere

Personal Outlook signatures silenced across Windows, Mac, web and new Outlook

Campaign banners

Marketing banners in every signature - scheduled, targeted and measurable

A/B testing

Run signature variants against each other and keep the one that performs

Recipient targeting

Different signatures for different audiences - internal, external, per domain, per tier

Reply-chain aware

Full signature on the first mail, a compact one deep in the thread - never stacked duplicates

Sent Items updated

The stamped signature written back into senders' Sent folders, so what they see is what was sent

Provenance and proof of send

Cryptographic verification any recipient or auditor can check

Data loss prevention

Credit cards, IDs and custom patterns caught at compose and at the gateway - before mail leaves

Signature intelligence

See the signatures your organization actually receives, and learn from them

Full audit trail

Every change, by whom, from where - with six role levels and per-organization isolation

Built for every team that touches email

IT

One dashboard for every mailbox. No scripts, no per-desk visits, no surprises after updates.

Compliance and Legal

Disclaimers that always apply, provenance an auditor can check, DLP before mail leaves.

Marketing

Campaign banners in every signature, scheduled and A/B tested like a real channel.

Security

Per-tenant encryption, full audit trail, and a mail path that never blocks delivery.

Ready to sign every email properly?

See StampFlow on your own tenant, or talk to us about running it inside your infrastructure. We reply within one business day.