Batch Mailbox Migration with Parallel Workers
Organize mailboxes into batches and run them with up to 10 parallel workers by default. Worker concurrency is configurable — scale up or down depending on your environment and API rate limits.
Migrate Microsoft 365 email to Google Workspace —
fully from your machine
From
Microsoft 365
To
Google Workspace
TenantBridge migrates Microsoft 365 mailboxes to Google Workspace Gmail using parallel batch workers — with date range filters, an auditable per-message ledger, and jobs that survive interruptions and pick right back up.
Runs locally, never internet-exposed
Picks up where it left off after restarts
Credentials stored encrypted on your machine
Single download, no install dependencies
TenantBridge · Migrate
● Live
Email batch A · 80 mailboxes
Microsoft 365 → Google Workspace
Running
Email batch B · 80 mailboxes
Microsoft 365 → Google Workspace
Running
Email batch C · 80 mailboxes
Microsoft 365 → Google Workspace
Queued
Calendar sync · 240 users
Microsoft 365 → Google Calendar
Done
Four steps to a complete email migration
A clear, predictable path from connector setup to parallel workers running — no surprises mid-project.
Set Up M365 and Google Workspace Connectors
Enter your Microsoft 365 and Google Workspace credentials once in the Connectors view. Choose between Microsoft Graph or IMAP as the M365 source. Connectors are saved globally and reused across every project — no re-entering credentials for each migration.
Create Mailbox Batches
Organize mailboxes into batches — a project can have multiple batches for different user groups, departments, or migration waves. Each batch gets its own settings and runs independently.
Configure Date Filters and Options
Set a date range to limit which messages are migrated — useful for phased migrations where only recent mail should move first. Configure parallel worker counts, destination labels, and other per-batch options. Nothing runs until you say so.
Run Parallel Workers and Monitor
Switch to Migrate and start the batch. Workers run in parallel across mailboxes — email counts, transfer rates, and current mailbox update live. If the job is interrupted, the per-message ledger ensures nothing is re-sent or silently skipped when it resumes.
Built for Microsoft 365 to Google Workspace email migrations
Every capability you need to move mailboxes at scale — parallel workers, date filters, per-message tracking, and restart-safe state.
Date Range Filtering
Limit each batch to messages within a specific date window. Use this to migrate only recent mail in the first wave, then backfill older messages in a second pass — giving users immediate access to current email without waiting for a full transfer.
Microsoft Graph or IMAP
Connect to Microsoft 365 via the Microsoft Graph API for full mailbox access, or use IMAP for environments where Graph access isn't available. Both connection methods are supported from the same connector setup screen.
Auditable Per-Message Ledger
Every migrated message is recorded in a ledger as it completes. If the job is interrupted and resumed, already-migrated messages are skipped cleanly — nothing is duplicated, nothing is silently dropped.
Restart-Safe — Picks Up Mid-Batch
Job state is saved continuously as the migration runs. If the app closes or the machine restarts, TenantBridge picks up automatically from the last saved position — no re-migrating messages already transferred.
Credentials Encrypted on Your Machine
Microsoft 365 and Google Workspace API credentials are encrypted before being saved to the local database. They are never sent to a third-party server, never visible in exports, and only decrypted in memory when a job needs them.
Email migration questions
How many mailboxes can TenantBridge migrate at once?
TenantBridge runs email migrations with parallel workers — the default is 10 concurrent mailboxes per batch, and that limit is configurable. You can organize mailboxes into multiple batches within a project and run them sequentially or at the same time.
Does it support shared mailboxes and distribution groups?
TenantBridge migrates individual and shared mailboxes. Distribution groups are not mailboxes and are not migrated directly — those are typically re-created in the destination tenant as part of the cutover plan.
Can I filter email by date range?
Yes. Each email migration batch supports a date range filter so you can limit the transfer to messages within a specific window — useful for phased migrations or when you only need recent mail in the destination on day one.
What happens if the migration is interrupted mid-batch?
TenantBridge uses an auditable per-message ledger. If the migration is interrupted, the job resumes from where it left off when you reopen the app — already-migrated messages are not re-sent, and no messages are skipped silently.
Does TenantBridge support Microsoft Graph and IMAP?
Yes. TenantBridge can migrate email from Microsoft 365 using the Microsoft Graph API or via IMAP. The connection method is selected when you configure the source connector — useful if Graph access is restricted in your environment.
Ready to migrate your Microsoft 365 email?
Request a demo or reach out — we'll walk you through it.