Your signature, always on-brand.
Everywhere. Automatically.
OneSignature gives every employee a perfect, up-to-date email signature in Outlook — managed centrally by your team, filled with live data from Microsoft 365, and smart enough to serve the right signature to the right audience: a polished one for external contacts, a slim one for replies, automatically.
Hi Sarah,
Thanks for the call — I've attached the proposal and look forward to your thoughts. Let's reconnect next week.
Best,
Jake Wyler
Director of Marketing
+1 (303) 555-0148
jake@acme.com
Denver, CO
100%
on-brand, every send
0
user data on our servers — by default
4
platforms, one signature
~10 min
from manifest link to rollout
Let's be honest — email signatures are a mess
They're the most-seen piece of your brand — and the most neglected. Sound familiar?
Outdated a week after the promotion
Titles change, departments move, people get new phone numbers. Hand-built signatures are stale the moment they're sent.
Forty-two different signature styles
Every employee hand-rolls their own fonts, colors, and layouts. Your brand identity gets diluted with every single email.
Broken on half your devices
A signature built in Word looks fine on Windows — then explodes into a formatting nightmare on a phone or in a reply thread.
“Can you fix my signature?”
Signature support is a full-time job nobody asked for. It eats IT hours, generates ticket after ticket, and never stays fixed.
OneSignature fixes all of it. Forever.
Three steps. No fuss.
If you can send an email, you can get OneSignature running — it's designed to disappear into the background and just do its job.
Your admin designs it once
One beautiful, on-brand signature — built in a full editor, no HTML required. Start from 45 ready-made designs, give each team its own template, let replies use a slimmer version, and give external recipients a signature of their own.
WYSIWYG editor · 45 designer templates · per-team & per-audienceEveryone signs in with the account they already have
No new passwords, no per-person setup, no IT tickets. Your team's details — name, title, department, phone, photo — come straight from Microsoft 365.
Single sign-on · live profile dataIt just works — and stays fresh
Signatures appear automatically in new messages and replies across Windows, Mac, web, and mobile — and switch between your internal and external signatures live as recipients change. When someone gets promoted, their signature follows.
Auto-injected · self-updating · audience-awareUnder the hood, it's refreshingly boring
A client-side engine runs inside Outlook. That's the whole trick — and it's why the privacy story is so strong.
Your user's Outlook
the OneSignature engine runs here
- Pulls profile data straight from Microsoft Graph, on-device
- Stores signatures in the user's own mailbox
Your Microsoft 365 tenant
the single source of truth
- Live name, title, department, phone & photo
- Group membership drives which template applies
OneSignature's cloud only delivers your templates and policy — and only if your company opts in does it ever touch profile data (the on-behalf-of flow, off by default).
Serious under the hood, simple on the surface
Every feature is designed to serve two people: the admin who needs control, and the employee who just wants their email to look right.
Live data that never goes stale
Titles, departments, offices, phone numbers, and photos come straight from Microsoft 365 — and refresh automatically. Promoted yesterday? Your signature already knows.
External contacts get a signature of their own
Emailing a client? The polished outreach signature appears automatically. A quick note to a coworker? It stays slim. The swap happens live as recipients change — and you decide per audience: standard, dedicated, or no signature at all.
Different signatures for different teams
Assign a template to a group — or a group within a group. Sales gets its look, legal gets its disclaimer, everyone else gets the default. Inheritance is handled for you.
A real editor — plus HTML when you want it
A full WYSIWYG editor with one-click formatting, and a code view for the crowd who writes their own HTML. Everything gets checked so it renders safely in every email client.
One signature for new mail, another for replies
A complete, branded signature on fresh messages and a slim, tasteful one on replies. Because nobody wants the full brochure on a two-word “Thanks!”
Start from 45 designer templates
Skip the blank page. Modern card-style designs — rounded corners, tasteful color, clean typography — render safely in every email client. Pick one, add your brand, done.
User freedom — inside the guardrails
People can personalize their own signature, right from the task pane. Admins can regenerate from the latest template or reset a user's customizations at any time.
Privacy by design, not by policy
Zero-server by default: profile data is fetched on the device and stored in the user's own mailbox. Your data is never copied to a third-party directory.
Your users' data stays where it belongs
Most signature tools copy your entire directory to their servers to do this job. We built OneSignature backwards on purpose — so that's simply not required.
No directory sync. Ever.
We don't bulk-import your users, their photos, or their contact details anywhere.
On-device by default
Profile data is fetched from Microsoft Graph on the user's device and stored in their own mailbox. Our servers see none of it.
Your call, not ours
Companies that want server-side profile refresh can opt into our on-behalf-of flow. It's off unless you turn it on.
Compliance-friendly posture
For regulated industries, that means less attack surface, fewer data flows, and a story you can actually defend.
Zero-server architecture
The add-in runs on the user's device, talks directly to their own Microsoft 365 tenant, and stores signatures in their mailbox. There is no “our copy of your directory” to hack, leak, or subpoena.
How does it stack up? Pretty well.
Against the hand-rolled status quo, and against the server-hungry tools that came before.
| The old way | Typical signature tools | OneSignature | |
|---|---|---|---|
| Brand consistency | Every employee a wildcard | Set once, usually central | 100% on-brand, enforced |
| Profile data freshness | Stale the day it's written | Synced periodically | Live from Microsoft 365 |
| Works on every device | Windows maybe, pray for mobile | Usually desktop-first | Windows, Mac, web, mobile |
| User data on third-party servers | N/A — it's on your machines | Yes — your whole directory | Only if you opt in |
| Per-team templates | Hand-maintained chaos | Sometimes, with effort | Group-based, with inheritance |
| Signatures for external recipients | Everyone sees the same one | Rarely supported | Automatic — full, slim, or none |
| Time to deploy | IT tickets for weeks | Days of integration | About 10 minutes, one link |
Questions? Good.
The short, honest versions of the things people ask us most.
Do employees have to install anything?
No. Your admin deploys OneSignature once from the Microsoft 365 admin center using a single manifest link — then it's available to everyone automatically, on every Outlook they use.
What happens when someone gets a promotion or changes departments?
Their signature updates itself. Profile details like title, department, and phone come live from Microsoft 365, and the signature refreshes on a regular cycle — no IT involved.
Can employees still personalize their signatures?
Yes. Anyone can open the OneSignature task pane and edit their own signature — but the admin can always regenerate from the latest company template or reset customizations. Freedom, within the guardrails.
Which Outlook apps does it work in?
Windows (classic and new Outlook), Mac, Outlook on the web, and Outlook mobile. Signatures are injected consistently everywhere.
Where does user data actually live?
On the user's device and in their own mailbox. The OneSignature cloud delivers templates and policy; profile data is fetched directly from your Microsoft 365 tenant on the device. Server-side profile refresh only happens if your company explicitly opts in.
What does the WYSIWYG editor support?
All the formatting you'd expect — fonts, colors, images, tables, social icons — plus a code view if you prefer to write HTML. Saved signatures are validated so they render cleanly in email clients.
Do we have to design a signature from scratch?
No. The template gallery has 45 ready-made designs — modern card-style layouts with rounded corners that render cleanly in every email client. Pick one, drop in your brand colors and contact details, and you're done.
Can different teams have different signatures?
Absolutely. Assign templates to groups, and group membership — including inherited membership — decides which signature each person gets, with a company default as the fallback.
Can external contacts see a different signature?
Yes — automatically. When a message goes to someone outside your organization, OneSignature switches to the signature you designed for outreach, and swaps back the moment external recipients are removed. You control it per audience: external contacts can get the standard signature, a dedicated outreach one, or none at all.
Ready to look great in every inbox?
One signature. Live data. Zero compromise on privacy. Your team can be sending on-brand email by the end of the hour.
Uses the Microsoft 365 sign-in you already have — no passwords, no new accounts.