Migrating Email Platforms: A Complete Guide for SaaS

Migrating email platforms is intimidating. You're moving subscriber data, rebuilding sequences, updating integrations, and risking deliverability - all while keeping email flowing to your customers. This guide makes migration manageable with a step-by-step approach.

When to Migrate

Migration is worth the effort when:

• Outgrowing current platform: Missing features you need, hitting limits
• Cost problems: Pricing doesn't scale or features are overpriced
• Integration gaps: Can't connect to your billing or product systems
• Deliverability issues: Persistent inbox placement problems
• Support failures: Can't get help when you need it

Don't migrate just because something new looks shiny. Migration has real costs in time, risk, and temporary disruption.

Migration Planning (2-4 weeks before)

Audit Current State

Document everything in your current platform:

• Subscriber data: Total contacts, segments, custom attributes
• Sequences: All automations, triggers, timing
• Templates: Email designs, shared content blocks
• Integrations: What's connected and how
• API usage: Custom code that calls the platform
• Performance data: Historical metrics you want to preserve

Map to New Platform

For each element, understand:

• Does the new platform support this feature?
• Is there a 1:1 equivalent or will you need to rebuild?
• What's the best way to migrate it?

Set Up New Platform

Before moving anything:

• Create account and configure settings
• Set up authentication (SPF, DKIM, DMARC)
• Configure custom sending domain
• Build and test one sequence end-to-end

Data Migration

Subscriber Export

Export all subscriber data from your current platform:

• Email addresses (required)
• Names and custom attributes
• Subscription status and preferences
• Tags and segment memberships
• Activity history (if available)
• Engagement data (opens, clicks)

Most platforms export to CSV. Check for data format requirements on the new platform before importing.

Subscriber Import

Import carefully to preserve data integrity:

• Map fields correctly between platforms
• Preserve subscription status (don't re-subscribe unsubscribed users)
• Import in batches if the list is large
• Verify counts match after import

Sequenzy supports bulk imports with automatic field mapping and duplicate handling.

Suppression Lists

Critical: migrate your suppression lists:

• Unsubscribed users
• Hard bounces
• Spam complaints
• Manual suppressions

Failing to migrate suppressions risks sending to people who opted out - a deliverability and compliance disaster.

Sequence Migration

Priority Order

Migrate sequences in order of business impact:

1. Transactional: Password resets, receipts (can't be down)
2. Trial conversion: Direct revenue impact
3. Dunning: Prevents churn
4. Onboarding: Critical for new users
5. Marketing: Can wait if needed

Rebuilding Sequences

For each sequence:

1. Document the logic: triggers, timing, conditions
2. Export/copy email content
3. Rebuild in new platform
4. Test thoroughly before activating
5. Verify data flows correctly

Consider this an opportunity to improve. You'll often find sequences that could be better.

Integration Migration

Billing Integration

If you're using Stripe integration:

• Disconnect from old platform
• Connect to new platform
• Verify subscription data syncs correctly
• Test billing events trigger sequences

Sequenzy offers native Stripe integration that syncs automatically - no webhook configuration needed.

API Integration

Update any custom code:

• Identify all API calls to old platform
• Update to new platform's API
• Test in staging before production
• Deploy during low-traffic period

Third-Party Integrations

Reconnect tools like:

• CRM systems
• Analytics platforms
• Support tools
• Zapier/Make automations

The Cutover

Parallel Running

Run both platforms simultaneously during transition:

1. Keep old platform active for in-progress sequences
2. Start new subscribers on new platform
3. Gradually move active sequences
4. Deactivate old platform only when confident

Timing

Choose migration timing carefully:

• Avoid peak business periods
• Don't migrate during a major campaign
• Allow time for issues to surface before high-stakes sending
• Have team available to monitor and fix problems

DNS Changes

If changing sending domains:

• Update SPF records for new platform
• Add DKIM keys for new platform
• Keep old records briefly for in-flight emails
• Remove old records once migration complete

Protecting Deliverability

IP Warming

If moving to new IPs (dedicated or new shared pool):

• Start with small sends to engaged subscribers
• Gradually increase volume over 2-4 weeks
• Monitor bounce and complaint rates closely
• Pause and investigate if issues arise

Domain Reputation

Your domain reputation travels with you:

• Good reputation makes migration smoother
• Bad reputation follows you to new platform
• Migration won't fix fundamental deliverability issues

Monitoring

Watch these metrics closely post-migration:

• Delivery rates
• Bounce rates (especially hard bounces)
• Spam complaint rates
• Open rates (as proxy for inbox placement)

Post-Migration Checklist

• All subscribers imported with correct attributes
• Suppression lists in place
• All sequences rebuilt and tested
• Integrations reconnected and verified
• API updates deployed and working
• Authentication (SPF, DKIM) configured
• Team trained on new platform
• Old platform cancelled (after retention period)
• Documentation updated

Common Migration Mistakes

• Rushing: Take time to plan and test
• Forgetting suppressions: Always migrate unsubscribes
• Not testing: Verify sequences work before activating
• Big bang cutover: Parallel running is safer
• Ignoring deliverability: IP warming matters
• No rollback plan: Keep old platform accessible briefly

Make Your Next Migration Easier

Choose platforms that make migration straightforward. Sequenzy offers import tools, native integrations, and support to help you migrate smoothly from any platform.