How to Migrate Slack to Google Chat

Introduction

When an organization decides to migrate from Slack to Google Chat, the IT admin usually leads the entire Slack to Google Chat migration — from identifying the right migration product to completing the migration.

The process involves more than just moving messages — it also includes channels, direct messages, files, reactions, emojis, and current workflows, so picking the right way and tool for migration is just as important as the migration itself. ZuniPixel manages this entire process automatically.

Why organizations are moving from Slack to Google Chat

ZuniPixel identifies three main reasons organizations switch from Slack to Google Chat: reducing duplicate license costs, supporting mergers and acquisitions, and preparing for new AI features.

Reducing duplicate license costs

Google Chat comes with all Google Workspace plans, starting with Business Starter. Companies that pay for both Google Workspace and Slack pay extra without gaining additional benefits.

Supporting mergers and acquisitions

Consolidating file storage, email, and chat into one system simplifies management. Migrating from Slack to Google Chat centralizes messaging, Drive, and Docs on a single platform rather than across multiple platforms.

Centralized administration

When Slack runs alongside Google Workspace, IT teams have to manage two separate systems for user accounts, security policies, and access permissions. Moving to Google Chat brings everything into the Google Admin console, so user accounts, security policies, chat permissions, Shared Drives, and Google Meet settings are all managed in one place.

This also changes the daily experience for employees, not just IT admins. Files from Google Drive can be shared directly in a conversation, documents can be edited without leaving Google Chat, and Google Meet sessions can be joined instantly from a chat. All of this happens without switching between separate applications.

Some of these differences — like API rate limits and report handling at scale — matter more during large migrations. See common-migration-challenges for what happens behind the scenes.

Preparing for AI features

Gemini in Chat, which offers AI-powered search, summaries, and translation, is available with the Business Standard plan and higher. To use Gemini across all tools, chat history needs to be in Google Chat, not Slack. Moving ensures conversations are available in the same AI system as Docs, Drive, and Gmail.

Slack vs Google Chat: what's actually different

Google Chat limits threads to 500 replies, which might surprise users after switching. If a Slack thread is too long, it will not fit in one Google Chat thread. ZuniPixel solves this by starting a new thread when the limit is reached and moving the remaining messages there in order, so no conversation is lost.

Understanding the technical differences between Slack and Google Chat helps IT admins plan for these changes, rather than discovering them after the migration.

What migrates from Slack to Google Chat

The table below lists the specific features of ZuniPixel's Slack to Google Chat migration. This helps IT admins compare migration tools based on real needs. For example, Google Chat requires every Space to have an owner. If a Slack channel without an owner is copied, it can cause problems and disrupt the migration.

ZuniPixel takes care of this automatically, along with other special cases listed in the table. For example, it handles the 200 MB file size limit in Google Chat by moving large files to Google Shared Drive. Private channels and direct messages require an additional step — user consent — since Slack doesn't expose this data without it. For a detailed look at how ZuniPixel handles consent, authentication, and role mapping for private channels and DMs, see our private channels and DMs authentication process.

Pre-migration checklist for admins

Before starting a Slack to Google Chat migration, IT admins should complete a short readiness checklist. This helps make sure the migration is properly planned and helps prevent delays.

Administrator access

Migration requires admin credentials for both Slack and Google Workspace, as ZuniPixel connects directly to both platforms.

Google Workspace licenses

Each user included in the migration must have an active Google Chat license before migration begins.

Channels & DM scope

Find out how many Slack channels need to be migrated and how many are public or private. ZuniPixel's pre-migration scan gives a full view of the workspace, including public, private, direct, inactive, and archived channels, to help define the scope before migration.

Check if direct messages and external Slack Connect channels are included in the migration. Some organizations have customers or partners connected through these channels, so make this decision early. Deciding early helps reduce unnecessary communication during migration.

User authentication readiness

Slack requires each user to authenticate before private channels and direct messages can be migrated, for security. ZuniPixel automates this by emailing each Slack user a consent request that links to Slack's login page. IT admins can track authentication status in the dashboard and resend requests to anyone who hasn't completed it. Because this depends on each user and can take time, start it right after setup, alongside public channel migration, rather than waiting for everyone to finish.

The migration process, step by step

1. Connect

ZuniPixel connects to both Slack and Google Workspace using secure OAuth 2.0, so no passwords are stored during setup. Admin credentials are needed for both platforms. Once connected, ZuniPixel pulls user lists from Slack and Google Workspace, along with the list of Slack public channels, and shows the workspace name and total user count for both platforms in the ZuniPixel dashboard.

2. Scan

ZuniPixel runs a pre-migration scan of the Slack workspace, checking the number of channels and the number of members in each channel. This gives IT admins a clear view of the migration scope before anything is moved.

3. Map

ZuniPixel matches Slack users to their Google Workspace accounts automatically. IT admins can review matched and unmatched users in the interface and use CSV-based mapping as a backup for anything not matched. A user mapping report can be downloaded at any time. IT admins also choose which Slack channels to migrate and map each one to a Google Chat Space. ZuniPixel names each Space to match the Slack channel, but admins can rename Spaces before starting.

4. Migrate

After reviewing the selected channels, the admin initiates the migration with a single click. ZuniPixel creates a migration job that tracks every channel in one place, including total messages, messages migrated, and each channel's status.

Public channel migration can start right away and run at the same time as private channel and DM consent collection, so migration progress is not delayed by waiting for authentication. Each Google Chat Space stays in import mode during migration, letting ZuniPixel keep syncing new messages without interrupting the channel.

5. Track

After the initial sync, IT admins can run a delta sync for each channel or the entire migration job, capturing any messages sent after the initial sync. Tracking both initial and delta sync in one job view is faster than checking each channel separately.

ZuniPixel provides two types of reports on demand: a channel-level report showing total, migrated, and skipped messages, and a job-level report showing how many channels are in progress or completed. The dashboard gives IT admins a real-time view of every migration job.

When there are no more changes to sync, the IT admin closes the Space from the ZuniPixel migration job. Closing a Space switches it from import mode to regular mode, making the channel visible to all users in Google Chat. This change cannot be undone, and no more migration can be started for that channel. This is a Google Chat platform feature, not a ZuniPixel limitation.

Security and compliance

ZuniPixel builds security and compliance into the migration process, not just as a policy statement.

Authentication and encryption

Slack and Google Workspace connect via OAuth 2.0, so no passwords are stored at any time. Data is encrypted in transit using TLS 1.2 or 1.3 and at rest. ZuniPixel does not store messages or files on its own servers. Migration happens directly between Slack and Google Chat, so message and file content never passes through ZuniPixel's infrastructure. Metadata like mapping tables and processing logs is also encrypted at rest during migration.

Data residency

ZuniPixel supports flexible data residency, so companies with specific regional needs can choose where their data is processed.

Access control during migration

A dedicated migration manager leads each ZuniPixel migration from the pre-migration phase through completion. No other team member can access migration data, and all data remains encrypted throughout the process.

Audit visibility

IT admins need full visibility into what has been migrated and what is still in progress, especially for reporting status to stakeholders. ZuniPixel provides audit reports at every stage, including pre-migration scan reports, job-level reports, and initial and delta sync reports. This gives IT admins a documented record of the entire migration.

Data deletion after sign-off

Migration is considered complete once delta syncs show no remaining changes. At that point, a sign-off session confirms the customer has verified the migration, and the IT admin disconnects ZuniPixel's access to Slack and Google Workspace. After disconnection, all temporarily stored data, including Slack and Google user lists, channel names, and Space names, is deleted from ZuniPixel's systems.

Common migration challenges and how they're handled

External member access, thread reply limits, and file size restrictions are common concerns during migration. The Slack vs. Google Chat comparison and migration sections above explain how ZuniPixel handles each one. The challenges below show what happens at scale and behind the scenes.

Handling Slack API rate limits during large-scale migrations

Slack's API has rate limits that vary by endpoint, and each API used during migration has a different limit. If these limits are not managed, migration can slow down, and costs can increase for large-scale projects.

ZuniPixel manages both Slack and Google API rate limits with a built-in smart API rate-limiting system that respects each API's limits and uses them in parallel, so migration does not slow down. If a rate limit is reached, ZuniPixel's engine detects and handles it automatically in the background.

Migration report granularity

ZuniPixel provides two levels of reporting: job-level and sync-level. The job-level report shows the combined status of initial and delta sync across all channels in a migration job. The sync-level report gives more detail, showing initial and delta sync status separately, along with total messages, messages migrated, and each channel's status.

If a message is skipped, the report includes the exact reason from Google Chat's migration response. Reports can be exported at both the job and sync levels, providing IT admins with records for verification or audits.

What doesn't migrate

Bot and system messages are treated like regular message content and are preserved like any other message. However, the bot's active configuration or integration does not transfer. Bots must be set up again in Google Chat after the migration. ZuniPixel's workflow automation report, mentioned earlier, shows which Slack workflows can be recreated in Google Chat and which ones need manual setup.