Migration of your contact list to systeme.io: what you need to know before getting started (advanced tips)

Migrating your contacts to systeme.io may seem straightforward at first glance, but to avoid costly errors, such as undelivered emails, duplicates, or lost contacts, it is essential to follow a methodical process. Here are the most important points to keep in mind.

I. Preparation before migration

1. Clean your list

Inactive or invalid addresses can generate bounces:

a. Soft bounce: A temporary issue, such as when a recipient's inbox is full.

b. Hard bounce: A permanent issue, such as when an email address does not exist.

A high bounce rate directly impacts your sender reputation, which reduces the deliverability of your future emails.

Email providers like Gmail, Outlook, and Yahoo monitor your bounce rate. If you exceed certain thresholds (often 5%), your emails may end up in spam or be blocked entirely.

2. Identifying an "active contact"

An active contact is generally someone who:

a. Has opened or clicked on your emails recently (e.g., within the last 30-90 days).

b. Has not generated any bounces.

c. Has not reported your emails as spam.

3. Sorting your contacts

a. Sorting your contacts from your current email tool:

Filter the contacts in your current platform's list:

• Log in to your current email marketing tool or CRM.
• Go to the Contacts, Contact List, or Segmentation section.
• Access your contact list.
• Apply filters: Look for the Filter, Segment, or Create view option.

Example filters:

• Status = Active    (if your tool has an "active/inactive" field)
• Email opens > 0 in the last 90 days   
• Link clicks > 0 in the last 90 days   
• Bounce = None   
• Unsubscribed = No   

b. Sorting your contacts using an external tool:

To maintain a healthy contact list, use an email verification tool (such as ZeroBounce or NeverBounce) to identify invalid addresses.

Additionally, we recommend deleting contacts who have not interacted in a long time (6 to 12 months, depending on your sending frequency). Finally, remove generic or suspicious addresses, such as test@test.com    or admin@domain.com   .

4. Format verification

a. CSV format recommended: systeme.io only accepts CSV file formats. Each column should be correctly labeled (First Name, Last Name, Email, Tags, Registration Date, etc.).

b. UTF-8 encoding: To avoid corrupted characters, ensure your file is UTF-8 encoded.

c. Removing duplicates: Identify repeated emails to avoid having multiple entries for the same contact.

II. Segmentation of your contacts

Segmentation involves dividing your contact list into specific groups based on precise criteria: interests, behavior, age, location, purchase history, or any other relevant data.

It is important because:

1. Improved campaign effectiveness

a. Personalized and targeted emails generate significantly more interest. A message tailored to a contact's needs or preferences has a much higher open and click rate than a generic blast.

b. Reduced unsubscribes and complaints: A contact who receives irrelevant content is more likely to unsubscribe or mark your message as spam. These actions can quickly damage your sender reputation and harm deliverability of future emails.

c. Optimized relationships with your contacts: By sending the right content at the right time to each segment, you increase subscriber satisfaction and engagement while building a stronger, long-term relationship.

Segmentation examples:

• By interest/category: Product A, Product B.
• By behavior: Active customers, inactive prospects.
• By source: Web form, event, in-store purchase.

2. Impact on deliverability:

• Precise targeting reduces spam complaints and improves your domain reputation score.
• Email providers favor senders whose emails are frequently opened and clicked.

III. Double opt-in and GDPR compliance

This is important because double opt-in involves sending a confirmation email after registration to verify that the contact truly wants to receive your emails.

This ensures:

• Contacts are genuinely interested.
• Fewer unsubscribes and spam reports.
• Compliance with GDPR and other anti-spam laws (CAN-SPAM, CASL, etc.).

And its impact on delirability resumes in the following points:

• Contacts confirmed via double opt-in open your emails more frequently and are less likely to flag them as spam.
• Email providers analyze recipient behavior; a low complaint rate and high engagement increase overall deliverability.

IV. Data structure and custom fields

When preparing to import your contacts into systeme.io, it is important to understand the field types and segmentation options to ensure an efficient and organized migration.

1. Required vs. optional fields

The email field is required, as it serves as the primary identifier for each contact. Other fields, such as first name, last name, or phone number, are optional but very useful for personalizing your emails and improving engagement. Even if you don't use them immediately, keeping this information allows for better segmentation and targeting later on.

2. Custom fields

systeme.io allows you to add custom fields, such as birthdays, interest levels, or any other information relevant to your business. During the import, make sure to correctly map these fields so the data is placed in the right location. Accurate mapping makes creating personalized campaigns and automations much easier later.

3. Tags and segments

You can import your contacts with existing tags to maintain your current segmentation. Tags help group contacts based on behavior, interests, or their stage in the customer journey. This organization makes setting up targeted automations much simpler after migration and allows you to continue sending relevant emails to each segment.

V. Migration methods

If you are using our migration service, a migration manager can handle the import of your contact file. However, if you wish to perform this operation yourself, here are the methods and steps to follow.

1. Manual import via CSV

This method is suitable for all types of lists and offers total control over the fields and tags assigned to your contacts.

a. Advantages:

• Ability to check and correct data before importing.
• Complete control over tag assignments and custom fields.

b. Steps to follow:

• Go to Contacts → Import in systeme.io.
• Select your CSV file containing the contacts.
• Map the columns from the CSV to the corresponding fields in systeme.io (e.g., email, first name, last name, custom fields).
• Assign tags as needed to maintain your segmentation.
• Start the import and check the final report to ensure all contacts were imported correctly and no data was lost or mismapped.

2. Integrations and API

If you want to automate the migration from an existing CRM, you can use integrations or our API.

a. Advantages:

• Significant speed advantage over manual imports.
• Reduces human error during data entry or mapping.

b. Key points:

• systeme.io offers connectors via Zapier or direct API calls to sync your contacts.
• Respect API limits to avoid errors or blocks during import.
• Verify field mapping to ensure all data is transferred correctly, preventing any information loss.

These are the essential steps to follow when importing your contact lists during a migration to systeme.io. Following these steps ensures that your contacts are correctly transferred, tags are properly assigned, and your segmentation remains intact.

Important: Resuming email sending gradually (Email Warming)

When switching email service providers, it is crucial to understand that even if you are used to sending a high volume of emails, you must start at a lower volume on the new platform.

Gradual sending (warming up) allows you to:

• Establish your sender reputation with Internet Service Providers (ISPs) like Gmail, Outlook, and Yahoo.
• Reduce the risk of being blocked or landing in the spam folder, especially with a new platform.
• Progressively build a solid reputation for future campaigns, improving deliverability and subscriber engagement.

In practice, start by sending emails to a small segment of active contacts, then gradually increase the volume over several days or weeks. This ensures your messages continue to reach your subscribers' inboxes safely during the migration.

VI. Post-migration checks

1. Test send: Send a test email to a small segment to verify deliverability.

2. Import report: systeme.io provides a summary of successfully imported contacts and any errors. Analyze this report carefully.

VII. Advanced tips for a secure migration

1. Migrate in batches: If you have thousands of contacts, import them in small groups to better manage errors and warm up your list by segment.
2. Source tags: Add a tag to identify the source of your contacts (e.g., migration_2026   ) to track their post-migration behavior.
3. Anti-spam verification: Avoid sending a massive campaign immediately after importing; allow 24 to 48 hours for the servers to process your new contacts.
4. Security backup: Keep a copy of your original list before importing.
5. Bounce monitoring: After migration, monitor bounced emails to adjust your lists and avoid reputation issues.

VIII. Bonus: Optimizing your contacts after migration

1. Dynamic segmentation: Use tags and behavioral criteria to create automated segments over time.

2. Automations: Set up welcome sequences for migrated contacts to improve engagement.

3. Continuous analysis: Track open rates, clicks, and unsubscribes to adjust your strategy.