Personalised from your directory
Sigil reads each person’s name, title, phone, address, department, manager and up to 15 custom attributes from Microsoft Graph, then stitches them into your template automatically, for every mailbox.
Email signatures for every Microsoft 365 mailbox
Centrally managed Outlook signatures, personalised from Entra ID and updated in seconds. Works on Outlook for Windows, Mac, web, iOS and Android.
No credit card required · Set up in minutes
- Keep your brand
consistent - Easy to deploy
and manage - Built for Microsoft 365
(formerly Office 365)
ToPriya Sharma
SubjectRe: Q3 partnership proposal
Hi Priya,
Thanks for the quick turnaround. The revised terms look great. I've attached the updated deck and I'll get the agreement over to you shortly.
Best,
Alex
Alex Morgan
Head of Partnerships · Northwind Trading
M +44 7700 900321·E alex.morgan@northwind.co.uk
A 24 Kingsway, London WC2B 6NF
Smart signatures. Stronger brands.
Example data. Northwind Trading is a fictional company.
SecondsFrom publish to every mailbox
Read-onlyDirectory access, never write
One portalTemplates, rules, banners & analytics
£0.70Per mailbox / month (ex VAT), all-inclusive
Everything included
Centrally managed Outlook signatures for your whole organisation
Marketing wants brand and campaigns. Legal wants disclaimers. IT owns deployment. Sigil gives each of them exactly what they need, all from a single web portal.
Design once, two ways
A block-based drag-and-drop designer for marketers, or a full HTML editor with placeholder autocomplete for power users. Both compile to Outlook-safe, table-based HTML that renders everywhere.
Rules that assign themselves
Ordered assignment rules pick the right template per person: by department, office, email domain or Entra group membership. First match wins; everyone else gets your org-wide default.
Campaign banners
Drop a time-boxed, clickable banner above or below every signature. It runs on your own time zone, stays DST-correct, and always tracks click-throughs. Open and close campaigns in a click.
Compliance footers
Append a mandatory legal block at render time, per email domain, so no template can ever forget the disclaimer Legal signed off on. Set it once and it’s always there.
Instant updates
Rebrand, fix a typo, or swap a disclaimer, then publish. The next message every user composes carries the change. There is no redeploy and nothing to touch on any machine.
How it works
How Sigil deploys through Microsoft 365
Sigil works one way: an Outlook add-in that applies the signature as the message is written. Your mail flow stays exactly as Microsoft set it up, there are no connectors or transport rules to add, and the cutover is invisible to the people sending email. For the background on why that is the right trade-off for most tenants, read our guide to managing Outlook signatures across Microsoft 365.
- 01
Deploy once, centrally
An admin grants Sigil admin consent and deploys the Outlook add-in through Microsoft 365 Integrated apps. Nothing gets installed on individual machines, and there is no per-user setup. Microsoft says the add-in can take up to 24 hours to appear for every user.
- 02
Users just write email
The add-in runs automatically on every new message, reply and forward, and again when a user switches the sending account. The user never clicks a thing.
- 03
Sigil renders in real time
It signs the user in silently with their Entra ID, reads their directory attributes from Microsoft Graph, and merges them into your active template: Outlook-safe HTML with inline images.
- 04
The signature appears
Sigil inserts the finished signature into the message and suppresses any local one. The user sees a correct, on-brand signature every time, with zero effort.
Microsoft-nativeEntra ID sign-in, Microsoft Graph personalisation, Office add-in. No third-party directory sync.
Windows, Mac, web & mobileAutomatic on Outlook for Windows, Mac and the web, plus Outlook for iOS and Android.
Cloudflare-fastRuns entirely on Cloudflare’s edge, so rendering is quick wherever your people are.
Where it runs
Supported Outlook clients
Sigil runs wherever Outlook runs event-based add-ins. Once an admin has deployed it centrally, nothing is installed on any device.
| Client | Automatic apply | Notes |
|---|---|---|
| Outlook for Windows (classic) | Yes | Event-based add-ins in classic Outlook need Windows 10 version 1903 or later. A “My signature” button on the compose ribbon re-applies the signature if silent sign-in ever fails. |
| New Outlook for Windows | Yes | Shared mailboxes are covered when they are added as a full account. The ribbon fallback button is available. |
| Outlook for Mac | Yes | Requires the new Outlook for Mac interface; Microsoft does not run event-based add-ins in the legacy Mac UI. The ribbon fallback button is available. |
| Outlook on the web | Yes | Including a shared mailbox opened in its own browser tab. |
| Outlook for iOS | Yes | Needs Outlook for iOS 4.2352.0 or later for new messages, and 4.2502.0 or later to re-apply when the From account is switched. There is no manual fallback button on mobile. |
| Outlook for Android | Yes | Needs Outlook for Android 4.2352.0 or later for new messages, and 4.2502.0 or later to re-apply when the From account is switched. There is no manual fallback button on mobile. |
What Sigil doesn’t cover
- Mail sent from anything that is not Outlook: Apple Mail, the native Android mail app, printers and scanners, service accounts and line-of-business apps sending by SMTP. Sigil has no server-side mode, so those messages go out without a signature.
- On-premises Exchange. Sigil needs Microsoft 365 with Exchange Online, and Microsoft’s centralised deployment does not reach on-premises mailboxes either.
- A Microsoft 365 Group’s own space. Outlook does not run add-ins there, so a message on behalf of a group has to start from the person’s mailbox with the From field switched.
- Shared mailboxes on iOS and Android. Outlook add-ins do not run for shared mailboxes on mobile.
Sources, Microsoft Learn: Activate add-ins with events (supported clients), Event-based activation in Outlook mobile add-ins, Shared folders and shared mailbox scenarios, Centralized deployment FAQ.
See it in action
See Sigil working in Outlook (83-second demo)
A signature applied automatically inside Outlook, edited in the drag-and-drop designer, published live in seconds, and then proven mailbox by mailbox. No slides, just the real thing.
Read the transcript
- 0:03Signed automatically. A new message in Outlook, signature already in place.
- 0:26Drag-and-drop designer. Rearrange blocks and edit the template in the browser.
- 0:45Live in seconds. Publish, and the very next message carries the change.
- 1:11Proof it landed. Per-mailbox activity: who applied, and who never has.
Prove it’s working
Prove every mailbox has its signature
Traditional client-side signatures give you no feedback at all. Sigil closes the loop: every render and every apply is logged, so you can prove adoption across the whole organisation instead of just hoping for it.
- Per-mailbox activity: see who has applied their signature, and when.
- A never-applied list that surfaces mailboxes still missing their signature.
- An attribute coverage audit showing which directory fields are actually populated.
- An append-only change log of every admin action, for accountability.
Signature adoptionExample data
98.2%of mailboxes applied this week
98%
alex.morgan@ · applied · 2m ago
priya.sharma@ · applied · 4m ago
sam.lee@ · never applied
Security & privacy
Security, permissions and data handling
Sigil is Microsoft-native and privacy-first by design. It never reroutes mail, never asks for write access, and holds no data you wouldn’t want us to.
Read-only, always
Sigil asks only for read access to your directory, never permission to send mail or write to your tenant. It reads what it needs to personalise a signature, and nothing more.
Strict tenant isolation
Every template, image and cache entry is scoped to your tenant. Each request must carry a valid Entra-verified user token, and there are no shared secrets in the add-in.
Privacy-respecting analytics
Link tracking counts clicks only. No IP addresses, no recipient identities and no message content are ever stored. You get the numbers without surveilling anyone.
Yours to govern
DSAR export and DPA tooling are built in, with published privacy, terms and support pages. Your data stays your data.
Read the full security overview: the exact Graph permissions, sign-in, tenant isolation, sub-processors and how to report a vulnerability.
Pricing
Microsoft 365 email signature pricing
Simple and per-seat: no tiers, no feature gates, no annual lock-in. One price per mailbox, covering every feature Sigil has, for everyone. See full pricing
£0.70per mailbox / month, ex VAT
Billed monthly · excluding VAT · cancel any time
Start your 14-day free trialReal seats from day one. No payment details required to start.
- Shared & resource mailboxes are free.
- Seat count is read from your directory automatically.
- Guests and disabled accounts are excluded.
Every plan includes
- Drag-and-drop & HTML template authoring
- Directory personalisation from Microsoft Graph
- Reply & forward signatures
- Assignment rules by department, office, domain & group
- Campaign banners & compliance footers
- Adoption, coverage & link analytics
- Drafts, versioning & one-click rollback
- Unlimited templates, admins & editors
Running a smaller organisation, a charity, or something the flat per-seat price doesn't quite suit? Get in touch and we'll see what we can do.
Questions?
Frequently asked questions
All three can put signatures into Outlook. Sigil does it one way only: an Outlook add-in that applies the signature as you write, so your mail flow is never touched and there’s no server-side routing to configure or troubleshoot. Changes you publish reach the next message each person writes, and Sigil shows you which mailboxes have actually applied their signature. It costs £0.70 per mailbox per month, excluding VAT, with every feature included, and shared mailboxes are free.
Once an admin deploys Sigil through Microsoft 365, the add-in runs automatically whenever a user composes, replies to or forwards a message. It signs the user in silently with their Entra ID, renders their personalised signature, and inserts it. There are no clicks and no setup, and the whole thing stays invisible to the end user.
From Microsoft Graph. Sigil reads each user’s directory attributes (name, job title, phone, address, department, manager and up to 15 custom extension attributes) with read-only access, and merges them into your template. Conditional sections automatically hide fields a user doesn’t have.
There are two different clocks. First deployment is Microsoft’s: after you deploy the add-in through Integrated apps, Microsoft says it can take up to 24 hours to appear for every user, and up to 72 hours for a later add-in update. Everything after that is Sigil’s: a template edit reaches users in seconds, because publishing invalidates the cache and the next message a user composes carries the new signature. There is nothing to redeploy. Assignment-rule changes propagate within about 10 minutes.
Sigil applies automatically on classic and new Outlook for Windows, Outlook for Mac, Outlook on the web, and Outlook for iOS and Android. It requires Microsoft 365 with Exchange Online. Mail sent from clients other than Outlook, such as Apple Mail, does not get a signature, because Sigil has no server-side mode.
No. Because Sigil is client-side, the cutover is invisible and reversible. You can pilot it with a group first via assignment rules, then roll it out organisation-wide when you’re ready.
£0.70 per licensed mailbox per month, excluding VAT, billed monthly, every feature included, cancel any time. Shared, resource and group mailboxes are free. Start with a 14-day free trial, with no payment details required and real seats from day one.
Yes. Switch the From field in Outlook to a shared mailbox, a Microsoft 365 Group or a distribution list and that mailbox’s signature is applied, with the option of naming the colleague who actually wrote the message: “Jane Doe on behalf of Sales”. None of them cost a seat. The one thing Outlook itself doesn’t allow is add-ins inside a group’s own space, so a message must be started from the person’s mailbox with the From field switched.
Sigil requests read-only directory access only, never permission to send mail or write to your tenant. Each tenant’s data is strictly isolated, no secrets live in the add-in, and link analytics count clicks only: no IP addresses, no recipient identities and no message content are ever stored.
Get consistent signatures on every mailbox.
Centralise. Standardise. Simplify.
On-brand signatures on every Microsoft 365 mailbox. Set up in minutes, pushed out to everyone by Microsoft within a day, and updated in seconds after that. Start free and see it working across your tenant.
No credit card required · Set up in minutes · £0.70 per mailbox / month, ex VAT after