Here is how you can keep your email data complete and reliable throughout the migration process:
1. Create a data repository
Before moving anything, create a centralized data repository. This ensures you always have a reliable backup to cross-check against once the migration is complete.
Your repository should include:
Subscriber lists, including active, unsubscribed, and bounced contacts
Custom fields such as name, location, preferences, and tags
Segments and audiences
Consent and opt-in data, including timestamps, source, and IP address if stored
Campaign history like sends, opens, and clicks
Automation workflows and logic
2. Audit and clean your data
Once you have a complete data repository, the next step is to review and clean your data before migration. Moving unverified or inconsistent data into a new platform increases the risk of errors, broken workflows, and unreliable reporting.
Start by:
Removing duplicate contacts to avoid conflicting records
Adding hard bounces and unsubscribed contacts to a suppression list
Standardizing field names and formats such as dates, country codes, and boolean values
Checking for missing or incomplete values in required fields.
3. Map data fields precisely
Field mapping ensures that every piece of data from your old platform lands in the correct place in the new one. Without precise mapping, important information like consent status, tags, or preferences can be misplaced or lost.
To do this correctly, create a field-mapping document before migration. List each field from your old platform and map it to its corresponding field in the new platform. Include details such as data type, whether the field is required or optional, and default values when data is missing.
For example, you might map old.first_name → new.FNAME (text), old.opt_in_date → new.consent_date (datetime) or old.tag_premium → new.segment_premium (boolean).
4. Migrate in stages
Migrating all your data at once increases the risk of widespread errors that are difficult to track and fix. A staged migration approach helps you identify issues early and reduces the impact of any mistakes.
Start by migrating a small test batch, typically around five percent of your total data. Validate the results carefully, fix any mapping or formatting issues, and confirm that records appear correctly in the new platform.
Once everything checks out, proceed with the full migration. This step-by-step approach significantly lowers risk and gives you more control over the process.
5. Validate data after transfer
Once your data is migrated, it’s time to make sure everything actually made it over correctly. Even if the import says “success,” small issues can slip through, so it’s worth taking a careful look.
Start with some automated checks to catch obvious problems quickly:
Make sure your record counts match (or that any differences are expected)
Use hash or checksum comparisons for really large datasets
Look for missing or null values in fields that are required
Then do a few manual spot checks to catch anything the automated checks might miss:
Open up a few subscriber profiles and see if everything looks right
Check that tags, segments, and consent data are accurate
Make sure special characters like accents, emojis, or symbols didn’t break
Doing both automated and hands-on checks gives you confidence that your data is accurate and ready to go in the new platform
Final thoughts
Data integrity should never be an afterthought during an email tool migration. With proper backups, clean data, precise field mapping, staged migrations, and thorough validation, you can move platforms without compromising accuracy or compliance.
A careful approach not only prevents errors but also sets you up with a cleaner, more reliable email database that performs better long after the migration is complete.
