Sigsync Signatures for Office 365 - Overview

Sigsync Signatures for Office 365 is a Microsoft-approved, centralized, and secure web-based solution for managing email signatures across your organization without requiring any local installation. Built with enterprise-grade protection, Sigsync is SOC 2 Type II and ISO certified, and HIPAA and GDPR compliant, ensuring strong data security, privacy, and compliance throughout the signature processing workflow.

Using flexible, user-defined rules, Sigsync automatically applies consistent and professionally designed Office 365 signatures including banners, disclaimers, and branding elements to all outgoing emails. It supports multiple deployment options such as Centralized Mode, Server Mode, and Client Mode, giving organizations the flexibility to choose the configuration that best fits their requirements. Sigsync includes an intuitive Signature Editor and an extensive Template Gallery, where templates can be dynamically populated with Azure Active Directory (AAD) fields like name, title, department, and other user attributes, ensuring always-accurate and up-to-date signatures. The service works seamlessly across all email clients and mobile devices, ensuring consistent signatures on desktops, smartphones, and tablets.

As a fully web-based platform, Sigsync can be accessed and administered from any device or operating system including Windows, macOS, Android, and iOS providing reliable, centralized, and flexible control over your organization’s email signature management from anywhere.

How Does Sigsync Email Signature Work?

Sigsync processes email signatures based on the deployment mode configured for your organization. The recommended mode is Centralized Mode, as it combines both server-side and client-side processing to deliver the most complete, flexible, and consistent signature experience across all devices and platforms.

Each mode determines how signatures are inserted either after the email is sent (server-side) or directly while composing the message in Outlook (client-side). Sigsync uses Exchange connectors and routing rules when required and supports dynamic user information pulled from Azure Active Directory to ensure accurate, centrally managed branding.

The three deployment modes include: Centralized Mode, Server Mode, and Client Mode.

Centralized Mode (Recommended)

Centralized Mode is the preferred and most comprehensive method for deploying signatures in Microsoft 365. It begins with server-side processing and transitions to client-side insertion once the Outlook add-in becomes available to users. This ensures signatures are consistently applied from day one, even before the add-in is fully deployed across the organization..

Since Microsoft manages the Outlook add-in rollout, deployment can take 6 to 72 hours depending on tenant size. Until the add-in appears for all users, signatures are applied server-side.

How Centralized Mode Works?

Phase 1 — Server-Side Processing (immediate after setup)

1. The user sends an email from any device or client (Outlook, OWA, Mac, mobile, etc.).
2. Microsoft 365 checks Sigsync routing rules and forwards matching emails to Sigsync over a secure TLS connection via the Outbound Connector.
3. Sigsync processes the email and applies the signature using configured Signature Rules and Azure AD fields.
4. The signed email is returned to Microsoft 365 through the Inbound Connector.
5. The recipient receives the email with the applied signature.
6. To show server-side signatures in the sender’s Sent Items, the admin must enable the appropriate setting in Sigsync.

Phase 2 — Client-Side Processing (after Outlook add-in deployment)

1. After Microsoft completes add-in propagation, users begin seeing the Sigsync Outlook add-in in their Outlook clients.
2. When composing an email, the signature is automatically inserted into the message.
3. Users may also manually insert, switch, or remove signatures from the add-in pane, depending on permission settings.
4. Emails sent directly through Microsoft 365 without passing through Sigsync servers.
5. The recipient receives the email exactly as composed, with the applied signature.

Centralized Mode ensures full cross-device consistency, real-time signature visibility, and reliable fallback to server-side processing whenever necessary.

Server (Cloud) Mode

Server Mode applies signatures entirely at the server level, with no Outlook add-ins required. Signatures are appended during mail flow and do not appear during email composition unless the Sent Items option is enabled.

How Server Mode Works?

1. The user composes and sends an email from any device or email client.
2. Microsoft 365 routing rules forward matching messages to Sigsync via the Outbound Connector (TLS).
3. Sigsync evaluates Signature Rules and applies the appropriate signature and Azure AD attributes.
4. The processed email is returned to Microsoft 365 via the Inbound Connector.
5. The recipient receives the signed message.
6. Signatures appear in Sent Items only if the admin enables this feature in Sigsync Settings.

Server Mode is ideal for organizations seeking strict centralized control with no user interaction.

Client Mode (Outlook Add-in)

Client Mode inserts signatures directly within the Outlook compose window through the Sigsync add-in. This mode does not route emails through Sigsync servers and offers full visibility during composition.

How Client Mode Works?

1. The user opens Outlook on Windows, Web, Mac, iOS, or Android.
2. The Sigsync add-in loads the user’s signature and Azure AD details.
3. The signature is automatically added when the user starts composing an email.
4. Users may also manually choose signatures through the add-in pane.
5. The message is sent directly via Microsoft 365 with no routing through Sigsync servers.
6. The recipient receives the email exactly as composed.

Client Mode is best for Outlook-focused environments where users need immediate compose-time visibility and flexibility.

Security and Performance:

Sigsync Email Signature for Office 365 prioritizes security, privacy, compliance, and high performance. The following measures ensure safe and efficient processing:

• Only emails from registered Office 365 tenants are accepted and processed. So, no other emails are accepted from third-party sources.
• Sigsync does not store or retain any user email data. Emails are only routed through the service for signature processing and immediately returned to Office 365.
• Sigsync does not alter the email body, subject, sender, or recipients. Only signature-related properties are added when required.
  • Minimal headers such as ‘X-Sigsync-Processed’ and ‘Received’ may be added for routing and traceability.
• No email content or header information is stored in logs. Only when a user requests troubleshooting are a few relevant headers temporarily logged and removed after the issue is resolved.
• Sigsync operates on scalable servers that automatically adjust based on incoming email volume.
  • Signature processing usually completes within seconds, typically not exceeding a 5-second delay.
• The solution adheres to industry-standard security and compliance certifications, including:
  • SOC 2 Type II
  • ISO-certified security practices
  • HIPAA compliance for protecting healthcare-related data
  • GDPR compliance for data protection and privacy
  • Microsoft Approved Solution, ensuring trusted integration with Office 365

System Requirements:

To use Sigsync Email Signature for Office 365, your environment must meet the following requirements: a compatible Office 365 plan with Exchange Online and global admin rights to register the tenant and configure signatures. The web-based dashboard works on all modern browsers, including Chrome, Firefox, Edge, and Safari, across Windows, macOS, Linux, Android, and iOS devices. For the Outlook Add-in (Client Mode), supported versions include Outlook for Microsoft 365 on Windows, Outlook 2019/2021, Outlook for Mac (version 16.59 and later with ‘New Outlook’ enabled), as well as Outlook for Android and iOS (latest versions). Shared mailboxes, aliases, hybrid Exchange environments, DKIM-signed emails, and MFA logins are also supported when properly configured. Learn more

Dashboard Components

Sigsync Dashboard is the central console where administrators manage all aspects of organization-wide email signatures. It brings together tenant registration, template design, rules configuration, subscription management, and license usage insights into one unified interface, making signature administration simple, scalable, and efficient.

Admins and Customers

Sigsync provides a flexible role-based access system for both direct organizations and reseller environments. The Account Owner holds complete authority over the dashboard and can assign any user as an Admin with one of the following permission levels:

• Permit full access – Complete access to all features, including tenant setup, signature management, rules, settings, and subscriptions.
• Permit only subscription management – Access limited strictly to billing, payment updates, and license handling.
• Permit only signature management (excluding subscriptions) – Allows full control over tenants, templates, rules, and signature settings but excludes all subscription and billing options.

For resellers, Sigsync includes structured roles such as Reseller Owner and Reseller Customer. A Reseller Customer can further assign a Reseller Customer Admin within their own environment. This delegated admin can manage tenant-level operations such as signature management, rules, and settings, while remaining within the permissions defined by their reseller account.

This hierarchy ensures that both organizations and resellers can securely manage signatures and permissions in a scalable, controlled manner.