Enterprise GAL Sync for Microsoft 365

Your Global Address List,
In Every Mailbox

SyncSE keeps personal contacts in sync with your organization's GAL across every target mailbox — automatically. On-prem today, cloud-ready tomorrow.

€1 / user / month
On-Prem Windows Service
M365 Graph API native
Cloud coming soon
Global Address List
SyncSE
Every Mailbox
GAL Full Sync
M365 Native Integration
On-Prem Deployment
€1 Per User / Month
24/7 Automated Sync

Three Steps to Sync

Deploy the service, configure your rules, and contacts stay current automatically.

1

Install the Service

Deploy the SyncSE Windows Service on your on-premises server. Configure your Microsoft 365 tenant connection via Graph API with your own app registration.

2

Define Sync Rules

Specify which GAL entries to sync using dynamic distribution groups or M365 groups as source and target. Set custom folders, filters, and schedules.

3

Contacts Stay Current

SyncSE continuously adds, updates, and removes contacts in target mailboxes. Every user sees an up-to-date address book without any manual effort.

Everything You Need for Contact Sync

From basic GAL sync to advanced multi-tenant scenarios, SyncSE covers it all.

Targeting

Smart Filtering

Synchronize only specific users based on custom filters or group membership. Use dynamic distribution groups or M365 groups to precisely control what gets synced.

Available
Organization

Custom Folder Sync

Sync contacts to a specific folder in each target mailbox. Keep synchronized contacts organized separately from personal contacts, with full cleanup support.

Available
Multi-Tenant

Cross-Tenant Sync

Synchronize users between tenants as organization contacts. Enable seamless address book visibility across merged or partner organizations.

Available
Automation

Dynamic Group Targeting

Use Dynamic Distribution Groups or Dynamic M365 Groups as both source and target. Sync from a specified source group to a specified target mailbox group automatically.

Available
Security

On-Premises Security

All processing happens inside your infrastructure. No contact data leaves your environment. Direct Graph API connection under your tenant's control with full audit logging.

Available
Operations

Cleanup & Maintenance

Remove all synchronized contacts, clear specific folders, or wipe all personal contacts. Selective cleanup by folder with optional folder removal for complete housekeeping.

Available
Coming Soon

Guest Synchronization

Synchronize users between tenants as guest accounts. Enable B2B collaboration by automatically provisioning and managing guest identities across organizations.

Planned

Two Ways to Deploy. Same Sync Engine.

Start with the on-premises Windows Service today. Transition to Azure Marketplace when you're ready. The core engine stays the same.

SyncSE Control Plane
MSI / ZIP Packages
Licensing / Updates
install & heartbeat
Your Environment
Admin / Operator
Config + Secrets
Windows Service SyncSE Windows Service
Microsoft 365 Exchange Online / Graph API
All data stays in your network
DPAPI-protected secrets
Optional heartbeat for updates
Azure Managed App / Marketplace
Portal / Monitoring
License / Registration
Cloud Sync Host Same GX sync engine
Graph API
Customer Tenant
Customer Secrets / Config
Microsoft 365 Exchange Online / Graph API
Zero infrastructure to manage
Built-in monitoring & portal
Same sync engine, managed hosting

Simple, Transparent Pricing

Pay per target mailbox. Volume discounts built in.

1 / user / month

starting price — volume discounts up to 20%

20–499 Standard base
500–1,999 Growth -10%
2,000–4,999 Business -20%

Your Data Stays With You

On-premises processing — all synchronization runs inside your infrastructure
No contact data transmitted — only update checks and usage metrics leave your network
Your Microsoft 365 credentials — direct Graph API connection under your tenant's control
Full audit trail — every sync operation is logged locally for compliance
Learn About Our Architecture →

Frequently Asked Questions

What is SyncSE?

SyncSE is an enterprise service that synchronizes your Microsoft 365 Global Address List (GAL) to personal contacts in user mailboxes. It runs as a Windows Service on your infrastructure and connects to your M365 tenant via the Graph API.

What does 'SE' stand for?

SE stands for 'Subscription Edition', reflecting our simple per-user monthly licensing model.

Why would I need GAL synchronization to personal contacts?

The Global Address List is only available within Outlook and Exchange-connected apps. Personal contacts, however, are available across all devices and applications — including mobile phones, Teams, and third-party apps.

By syncing GAL to personal contacts, your users can see their colleagues' contact information everywhere, not just in Outlook.

What exactly gets synchronized?

SyncSE synchronizes users and contacts from your GAL (or a filtered subset) to personal contact entries in target mailboxes. It handles the full lifecycle: adding new contacts, updating changed information, and removing contacts that are no longer in the source.

Can I sync contacts between different M365 tenants?

Yes. SyncSE supports cross-tenant synchronization, creating organization contacts in the target tenant from users in the source tenant. This is useful for mergers, partnerships, or multi-tenant organizations.

Where does SyncSE run?

SyncSE runs as a Windows Service on your on-premises server. All contact data processing happens within your environment. A cloud-hosted option is planned for a future release.

Does my contact data leave my network?

No. All synchronization processing is local. The only outbound communication is to the SyncSE update server for application updates and anonymous usage reporting. No contact data is ever transmitted.

What Microsoft 365 permissions are required?

SyncSE uses Microsoft Graph API with application permissions to read directory data and write personal contacts. You register your own Azure AD application with the minimum required permissions.

How does dynamic group targeting work?

You can specify a Dynamic Distribution Group or Dynamic M365 Group as both the source (which GAL entries to sync) and the target (which mailboxes receive contacts). This lets you automate who gets what contacts based on your existing group membership rules.

How is SyncSE priced?

SyncSE is priced at €1 per user per month, where a 'user' is a target mailbox receiving synchronized contacts. If you sync to 500 mailboxes, that’s €500/month.

Is there a free trial?

Yes. You can evaluate SyncSE in your environment with a trial period before committing to a subscription.

Do you offer volume discounts?

Yes. Contact our sales team for custom pricing on deployments with more than 5,000 target mailboxes.

Ready to Sync Your GAL?

Deploy SyncSE in minutes. Keep every mailbox's contacts current, automatically.