Native Microsoft 365 Signatures: Why They're Not Enough

Your company changes phone numbers, or you launch a new promotion to feature at the bottom of your emails. With native Microsoft 365 signatures, that means visiting every employee, on every device, hoping nobody forgets. That's the whole problem: signatures configured in Outlook live on the client side, not on the server side. The direct consequence: a server-side Microsoft 365 signature is applied automatically to every outgoing email — the same one for everyone, on any device — while the native signature depends on each workstation and each person's good will.

Client-side: what Outlook's native signature does

When an employee writes their signature in Outlook, it's saved on their device. That's what we call a client-side signature. It works, but it comes with blind spots.

• One device at a time. The signature on the laptop isn't the one on the tablet or the phone. Everyone has to recreate it everywhere.
• Mobile, often forgotten. The Outlook phone app adds "Sent from my iPhone" or nothing at all. Plenty of emails go out with no signature at all.
• Easy to change or delete. Anyone can edit their own, add a quote, remove the legal notice. You lose control.
• No bulk updates. New number, new title, new logo: you have to revisit every workstation, one by one.

The result is ten different versions of your signature circulating at the same time. For one person, no big deal. For a team of fifteen or fifty, it becomes a real image problem.

What about Microsoft 365's roaming signatures?

Microsoft added roaming signatures to solve part of the headache: the signature follows the account from one device to another instead of staying stuck to a single workstation. It's better, but it's still client-side in spirit. Three important limits remain:

1. Uneven coverage. Support depends on Outlook versions and doesn't cover all devices well, especially mobile.
2. The employee stays in control. They can still edit their signature. Nothing guarantees your legal notice or your logo stays in place.
3. No connection to your directory. Contact details don't fill themselves in from your employee records. Everything has to be maintained by hand.

In other words, the native options help an individual keep track of their signature. They don't give the organization the control it needs.

Server-side: one rule for everyone

A server-side signature works differently. Instead of living on each device, it's applied as the email passes through Microsoft 365, just before it's sent. In practice, that changes everything:

• Every email is covered — from the laptop, webmail or phone, with nothing to install on the device.
• The signature is identical across the whole company, or tailored by department, according to your rules.
• Contact details come from your directory. Name, title and phone number fill in automatically from your Microsoft 365 profiles.
• One update, everywhere, all at once. You change the logo or add a promotion a single time, and it's in place for everyone the next morning.
• The legal notice is guaranteed. Nobody can remove it, because the employee never touches the signature.

The table, at a glance

When the native signature is enough (and when it isn't anymore)

Let's be honest: if you're on your own or a team of two, the Outlook signature does the job perfectly. No need for a system.

The need for a centralized signature appears when several people send emails on your behalf and those emails represent your company. You then want three things the native option doesn't really give you: a consistent image, a legal notice that's always there, and the ability to change everything in a few minutes instead of doing the rounds of the office.

How ATOM approaches this

That's exactly the gap ATOM Signatures fills: centralized signatures for Microsoft 365, applied server-side, hosted in Canada and designed to comply with Québec's Law 25. One console, a clean signature on every email, updates in minutes. The price is deliberately simple: $1 CAD per user, per month (prices vary and can change).

Our way of working is the same as with everything else: we start small, connect your Microsoft 365 quickly, and explain every step in plain language. If Outlook's native signature is enough for you, we'll tell you honestly. If you care about a solid image and a legal notice that never disappears, a server-side signature is simply the right tool for the job.