Migrating from Exclaimer to Sigil
What maps across, how to run both during a pilot, and how to switch Exclaimer off cleanly. For the side-by-side comparison, see the Exclaimer comparison page; this is the plan once you have decided.
Why teams move
Exclaimer applies signatures server-side through Exchange Online mail flow rules, client-side through the Exclaimer Outlook add-in, or both (Exclaimer: server-side vs client-side). Sigil does one thing: an Outlook add-in that applies the signature as the message is written, with per- mailbox proof that it did. Teams that move to it tend to say the same three things:
- Price and simplicity. Exclaimer sells Starter, Standard and Pro plans with features gated by plan (signature analytics on Pro only) and a 10-user minimum (Exclaimer: pricing and plans, checked 15 September 2026). Sigil is £0.70 per mailbox / month, ex VAT, with everything included and no minimum.
- Nothing in the mail path. No connectors, no transport rules, nothing to remove when a contract ends. That matters most to MSPs who would otherwise be a dependency in a client’s delivery path.
- Adoption you can see. The portal lists every mailbox that has applied its signature and every one that never has.
Be clear-eyed about the other direction too: if you rely on server-side stamping to cover mail from clients other than Outlook, Sigil will not cover it. The supported clients table says exactly what is and is not covered.
What maps across
| In Exclaimer | In Sigil |
|---|---|
| Signature templates | Templates in Sigil’s drag-and-drop designer or HTML editor. Start from the ready-made template, or paste your current HTML in and swap the fields for placeholders. |
| Rules that decide who gets which template | Ordered assignment rules by department, office, email domain or Entra group. First match wins; everyone else gets the default. |
| Legal disclaimers | Compliance footers, appended at render time per email domain, so no template can leave the disclaimer out. |
| Marketing banners and campaigns | Campaign banners: time-boxed, scheduled in your time zone, above or below the signature, with click counts. |
| Reply signatures | A shorter signature on replies and forwards, per template. |
| Shared mailboxes and send-as | Switch the From field in Outlook and that mailbox’s signature is applied, optionally naming the colleague who wrote it. Shared, resource and group mailboxes are free. |
| Server-side stamping for non-Outlook clients | No equivalent. Sigil has no server-side mode. Mail from Apple Mail, printers or applications sending by SMTP gets no signature. |
Running both in parallel with a pilot group
- Create an Entra group for the pilot: a few people from IT, one from marketing, one heavy mobile user.
- Connect Sigil and grant admin consent (three read-only Graph permissions; see the security overview).
- Deploy the Sigil add-in through Integrated apps, assigned to the pilot group only. Microsoft can take up to 24 hours to push it.
- Recreate your main template and add an assignment rule targeting the pilot group.
- If Exclaimer stamps server-side, exclude the pilot group from its rules so they do not get two signatures. If it uses its own add-in, remove the pilot group from that add-in’s assignment.
- Watch the adoption report for a week. Ask the pilot to send a new message, a reply, and one from a shared mailbox, on desktop and phone.
The deployment guide covers each step in more detail.
Switching Exclaimer off
Widen the Sigil assignment to everyone, wait for the adoption report to show the mailboxes you expect, then:
- Client-side: remove the Exclaimer add-in from Integrated apps. Microsoft says removal can take up to 24 hours to reach every user.
- Server-side: If you ran Exclaimer server-side, your tenant has Exclaimer connectors and mail flow rules that route outbound mail through Exclaimer’s service. Follow Exclaimer’s own removal instructions to take them out, and only after Sigil is applying signatures for everyone. The steps are in the Exclaimer knowledge base.
- Roaming signatures: if Exclaimer asked you to disable Outlook’s roaming signatures with a registry key or an organisation setting, you can leave that as it is; Sigil suppresses the local signature itself when it applies.
- Cancel the subscription once the last mailbox has moved, not before. Running both for a week costs less than a gap.
Migration questions
Can I keep Exclaimer running while I trial Sigil?
Yes. Assign the Sigil add-in to a pilot group in Integrated apps and target that group with an assignment rule. Everyone else keeps Exclaimer. If Exclaimer is stamping server-side, the pilot group will get two signatures until you exclude them from Exclaimer’s rules, so do that first.
Will the signatures look the same?
They can. The HTML editor takes your existing markup with the fields swapped for placeholders, so recipients need not notice the switch. Most teams take the opportunity to tidy the design at the same time.
How long does the switch take?
Portal set-up is minutes. Microsoft can take up to 24 hours to push the add-in to every user. Run the pilot for a week, then widen the assignment; the adoption report tells you when everyone has applied a signature and it is safe to turn the old tool off.
What does it cost?
£0.70 per mailbox / month, ex VAT, with every feature included, no minimum seat count, and shared, resource and group mailboxes free. The trial is 14 days with no card required.
Still deciding? The Sigil vs Exclaimer page compares the two side by side, with every Exclaimer statement linked to its source. Exclaimer is a trademark of its owner and is not affiliated with Sigil or Tophhie Cloud Ltd.