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Product · 12 September 2026 · The Footer365 team

Why server-side email signatures beat client-side add-ins

Why server-side email signatures beat client-side add-ins

If you have ever rolled out email signatures across a company, you know the pain: the signature looks perfect on the marketing manager's laptop and is completely missing when they reply from their phone on the train. The problem is almost always the same - the signature is being applied on the client, not the server.

Client-side signatures only cover the clients you configured

A client-side approach installs or configures a signature in each mail app: desktop Outlook, Outlook on the web, the iOS and Android apps, Apple Mail, and any third-party client your staff happen to use. Every one of those is a separate place to configure, and every new device is a gap. Miss one and that person sends unbranded, inconsistent email without anyone noticing.

It gets worse with replies and forwards, shared mailboxes, and staff who use more than one device. The signature drifts out of date the moment someone changes job title, and there is nothing central to correct it.

Server-side injection applies once, everywhere

Footer365 takes the opposite approach. Your signature is applied in Exchange Online transport - the same place your mail already flows through - as each message leaves your organisation. That means:

  • Every device and app is covered, because the signature is added after the message leaves the client.
  • There is nothing to install and nothing for staff to remember or configure.
  • Details like name, title and phone come from Entra ID, so they are always current.
  • You change a template once and every future email reflects it immediately.
The best signature rollout is the one nobody has to think about. It should just be correct, on every email, forever.

What about the pre-send preview?

The one thing server-side injection cannot do on its own is show the signature while someone is composing. For teams that want that, Footer365 includes an optional Outlook add-in that previews the applied signature at compose time - deployed centrally, with no per-user setup. You get the reliability of server-side injection and the reassurance of a live preview.

If you are evaluating signature tools, the single most important question to ask is where the signature is applied. If the answer is "on each device", you are signing up for a rollout that is never quite finished.

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