Signature 365 (by Symprex) is a cloud service for signatures in Microsoft 365. SignetMail is an alternative for companies that run Google Workspace as well as Microsoft 365, that want to host the server themselves or in the EU, or that have up to 50 users and want a free option. If you need ISO 27001 and SOC 2 certified vendors or phone support, Signature 365 is the more mature choice.
Disclosure: this comparison is written by SignetMail. Information on Signature 365 comes from their public pages (November 2026). Prices and features change, so check them with the vendor.
How do SignetMail and Signature 365 differ?
| SignetMail | Signature 365 | |
|---|---|---|
| Platforms | Microsoft 365 and Google Workspace in the same portal. | Microsoft 365. Google Workspace is not mentioned on their site. |
| Where it runs | On your own server (Docker or a Windows installer), or in the EU on request. | The vendor's cloud service (Microsoft Azure). Exchange on-premises is a separate product. |
| How the signature is added | Outlook add-in, an agent for classic Outlook on Windows, and the Gmail API for Gmail. Mail flow is unchanged. | Outlook add-in and optional routing of mail through their service. |
| Directory data | From Entra ID or Google Workspace, kept on your server. | From Microsoft 365, in the vendor's service. |
| Free | Up to 50 active users, every feature during the public beta. | 14-day trial. |
| Certifications | None (a young product). | ISO 27001, ISO 27018, SOC 2. |
| Support | E-mail, in Slovenian and English. | E-mail and phone, during UK business hours. |
When is SignetMail a good Signature 365 alternative?
- You also run Google Workspace. For example after an acquisition or across a group of companies. One tool manages signatures in Outlook and Gmail.
- Data must stay with you. You install SignetMail on your own server; the directory and signatures stay in your environment.
- You don't want to change mail flow. SignetMail does not reroute mail, so there are no SPF or connector changes.
- You are a smaller company. SignetMail is free for up to 50 active users.
- You want an EU vendor you can reach in your own time zone.
When should you stay with Signature 365?
- If your security policy requires a vendor with ISO 27001 or SOC 2 certification.
- If you need phone support and a contractual availability guarantee (SLA).
- If you want a service run entirely by the vendor, with no server of your own.
How do you switch from Signature 365 to SignetMail?
- Install SignetMail with Docker or the Windows installer and connect Entra ID.
- Bring your template over. Import the HTML of your current signature and replace the details with placeholders for name, title and phone.
- Set up rules for departments or groups, as you had them in Signature 365.
- Test with a pilot group. Assign the Outlook add-in to a few people first and check their signatures.
- Turn off Signature 365. Remove their add-in and, if you used it, the mail routing rule, so the signature is not added twice.
Frequently asked questions
Is SignetMail a free alternative to Signature 365?
For up to 50 active users, yes, with every feature during the public beta. Above 50 users you need a license on request.
Does SignetMail work in Outlook on phones?
Yes. The Outlook add-in works in Outlook for Windows, Mac, the web, iOS and Android. For classic Outlook on Windows there is also an agent.
Can I keep my existing signature design?
Yes. Import the HTML of your current signature and adjust it instead of starting over. See also Email signature software for Google Workspace and the comparison page.
Try SignetMail for free
Free during the public beta, with every feature and no card. We help pilot companies with the setup.