How to Add Custom Properties in Klaviyo

Klaviyo empowers marketers to create personalized, data-driven email and SMS campaigns that resonate with customers on an individual level. Custom properties serve as the foundation for this personalization, allowing you to store unique information about each customer beyond standard profile details. Adding these properties to your Klaviyo account opens up powerful segmentation and targeting capabilities that can dramatically improve your marketing effectiveness.

What Are Custom Properties and Why Do They Matter?

Custom properties function as specialized data fields attached to customer profiles in Klaviyo, storing information that goes beyond basic contact details. These properties capture virtually any type of customer data you need—from demographic information and product preferences to survey responses and purchase behavior. By leveraging custom properties, you gain deeper insights into your audience while creating more targeted campaigns that speak directly to individual interests and needs.

The strategic use of custom properties transforms generic marketing into personalized conversations with your customers. When you understand specific details about your subscribers—such as their birthday, preferred product categories, or communication frequency preferences—you can craft messages that feel tailored specifically to them. This level of personalization not only improves open and click-through rates but also strengthens customer loyalty and drives conversions.

Custom properties also enable sophisticated automation based on customer attributes. For example, you might trigger a special flow for customers who have indicated interest in a particular product category, or automatically send birthday offers when that date approaches. The flexibility of custom properties means you can design your customer data structure to align perfectly with your unique business needs and marketing strategy.

Types of Custom Properties You Can Create

Custom properties come in various forms, each serving different purposes in your marketing strategy. Understanding these types helps you determine which properties will be most valuable for your specific business needs.

Demographic properties provide fundamental insights about who your customers are. These might include age, gender, location details beyond basic address fields, occupation, or household information. Demographic data helps you understand the composition of your audience and tailor messaging appropriately for different customer segments.

Preference-based properties capture what your customers like and how they want to interact with your brand. These could include preferred product categories, shopping frequency, content interests, or communication preferences. By storing this information, you can ensure your marketing respects customer wishes while delivering content they actually want to receive.

Behavioral properties track how customers have interacted with your brand over time. Unlike event data that Klaviyo automatically captures, these properties might store aggregated information like lifetime purchase value, average order frequency, or loyalty program status. These insights help you identify your most valuable customers and create special experiences for them.

How to Add Custom Properties Through Customer Input

Collecting custom properties directly from your customers ensures you gather accurate, first-party data while building trust through transparency. When customers voluntarily share information about themselves, they expect you’ll use it to improve their experience—making this approach both effective and ethical for data collection.

Signup forms provide an excellent opportunity to gather initial custom property data. While keeping forms simple remains important for conversion rates, strategically adding 1-2 additional fields can significantly enhance your customer data. Consider which information would most impact your ability to personalize future communications, such as product interests or shopping preferences, and incorporate those fields into your signup process.

Preference centers offer another powerful method for collecting custom properties while giving customers control over their data. Creating a comprehensive preference center allows subscribers to update their information and communication preferences at any time. This approach not only gathers valuable data but also reduces unsubscribes by providing alternatives to opting out completely.

Designing Effective Forms for Data Collection

Creating forms that successfully collect custom properties requires balancing your data needs with user experience considerations. Thoughtfully designed forms encourage completion while gathering the information most valuable to your marketing efforts.

Field selection deserves careful consideration when building data collection forms. Each additional field creates friction that might prevent form completion, so focus on collecting only the most impactful information. Ask yourself which 1-3 custom properties would most significantly enhance your ability to segment and personalize communications, then prioritize those fields in your forms.

Field formatting affects both the user experience and data quality in your Klaviyo account. For dropdown menus, limit options to meaningful choices that support your segmentation strategy. For text fields, consider adding placeholder text that demonstrates the expected format. Date fields should clearly indicate the required format (MM/DD/YYYY or similar) to ensure consistency in your database.

Progressive profiling techniques allow you to gather comprehensive customer data over time rather than all at once. Instead of creating lengthy initial forms, collect basic information first, then use subsequent interactions to gather additional custom properties. This approach respects user experience while still building robust customer profiles through a series of manageable interactions.

How to Import Custom Properties Using CSV Files

Bulk importing custom properties through CSV files offers an efficient method for updating multiple profiles simultaneously. This approach proves particularly valuable when migrating from another platform, enriching your database with third-party data, or implementing new custom properties across your existing subscriber base.

Preparing your CSV file correctly ensures a smooth import process and accurate data. Your file should include a column for email addresses (or phone numbers for SMS contacts) to identify each profile, followed by columns for each custom property you wish to add or update. Use clear, consistent header names that match your intended custom property names in Klaviyo to simplify the mapping process during import.

The import process itself involves several key steps to ensure your data transfers correctly. Navigate to the Lists & Segments section of your Klaviyo account and select the appropriate list for your import. Choose the CSV file you’ve prepared, then carefully map each column to the corresponding Klaviyo field or custom property. For new custom properties, you’ll need to create them during this mapping process by typing the desired property name and selecting “Create New Field.”

Formatting Custom Properties for Successful Imports

Proper formatting ensures your custom property data imports correctly and functions as expected within Klaviyo. Different property types require specific formatting approaches to maintain data integrity.

Date properties require consistent formatting to function properly in Klaviyo’s system:

• Use standard date formats like YYYY-MM-DD or MM/DD/YYYY
• Ensure all dates follow the same format throughout your CSV
• For birthdays without years, consider using a consistent placeholder year
• Verify that dates appear correctly after import by checking sample profiles

List-type properties allow you to store multiple values within a single custom property, which proves useful for preferences or multiple selections:

• Format as JSON arrays using square brackets and quotes: [“Option1”, “Option2”]
• Ensure consistent spelling and capitalization of options
• Avoid using commas within individual options as this may cause parsing errors
• Test with a small sample before importing your entire database

Numeric properties should follow consistent formatting rules to support mathematical operations and comparisons:

• Use plain numbers without currency symbols or special formatting
• Use periods rather than commas for decimal places
• Remove any thousands separators from your data
• Consider standardizing to a specific number of decimal places for consistency

How to Manually Add and Edit Custom Properties

Sometimes you’ll need to add or modify custom properties for individual profiles rather than through bulk processes. Klaviyo provides straightforward methods for these one-off updates, whether you’re testing new properties or making specific adjustments to key customer profiles.

Adding custom properties to individual profiles takes just a few clicks within the Klaviyo interface. Navigate to the specific profile you wish to update, then locate the “Custom Properties” section. Click “Add Custom Property,” enter your property name and value, then save the changes. This manual approach proves particularly useful when working with VIP customers or when testing how new properties appear before implementing them more broadly.

Editing existing custom properties follows a similar process but requires attention to detail to maintain data consistency. When modifying property values, ensure you follow the same formatting conventions used for other profiles. Remember that changes are case-sensitive, and inconsistent formatting can create segmentation challenges later. For property names, editing should be approached cautiously as renaming may effectively create a new property rather than modifying the existing one.

Best Practices for Custom Property Management

Maintaining clean, consistent custom property data requires ongoing attention and clear protocols. Following these best practices helps ensure your custom properties remain valuable assets rather than becoming cluttered or confusing.

Naming conventions establish the foundation for organized custom property management:

1. Choose a consistent capitalization pattern (camelCase, snake_case, or other) and apply it to all properties
2. Use descriptive but concise names that clearly indicate the property’s purpose
3. Avoid special characters or spaces that might cause technical issues
4. Document your naming convention and share it with team members who access Klaviyo

Data validation processes help maintain the integrity of your custom property data:

• Regularly audit profiles to identify inconsistent or unexpected values
• Create internal guidelines for acceptable formats and values for each property
• Consider implementing form validation for customer-facing data collection
• Periodically clean data to standardize formatting and correct obvious errors

Documentation ensures everyone on your team understands your custom property structure and usage. Create and maintain a comprehensive property dictionary that includes:

• Complete list of all custom properties in use
• Description of each property’s purpose and intended use
• Acceptable values or formats for each property
• Which segments or flows utilize each property
• Who is responsible for maintaining each property

Using Custom Properties for Advanced Segmentation

The true power of custom properties emerges when you use them to create highly targeted segments for your marketing campaigns. Effective segmentation allows you to deliver relevant content to specific customer groups, dramatically improving engagement and conversion rates.

Basic segmentation with custom properties starts with simple conditions based on property values. For example, you might create segments for customers who have indicated specific product interests, who live in certain regions, or who have particular demographic characteristics. These straightforward segments provide a foundation for more personalized marketing without requiring complex technical skills.

Advanced segmentation techniques combine multiple custom properties with behavioral data to create highly specific audience groups. You might target customers who both prefer a certain product category (custom property) and have viewed related products recently (behavioral data). Or you could create a segment of high-value customers (based on a lifetime value custom property) who haven’t purchased in the last 60 days (behavioral condition).

Creating Dynamic Segments That Update Automatically

Dynamic segments continuously update based on changing customer data, ensuring your targeting remains accurate without manual intervention. These segments prove particularly valuable when working with time-sensitive or behavior-based marketing.

Condition-based segments automatically include or exclude profiles as their custom property values change:

• Customers who have birthdays in the current month
• Profiles with incomplete custom property data that needs updating
• Customers who have recently changed their preferences
• Subscribers who meet specific criteria for loyalty program tiers

Time-based segmentation leverages date properties to create automatically updating audiences:

1. Create segments for upcoming anniversaries or renewal dates
2. Build audiences for seasonal preferences that activate at appropriate times
3. Develop segments for subscription customers approaching their renewal date
4. Generate groups based on the recency of specific activities or milestones

Combining dynamic segments with flows creates powerful automated marketing sequences that respond to changing customer attributes. For example, when a customer’s “loyalty_points” custom property crosses a threshold value, they could automatically enter a flow congratulating them on reaching a new tier and explaining their new benefits.

Personalizing Content With Custom Properties

Custom properties enable truly personalized content that speaks directly to each recipient’s interests, preferences, and characteristics. This personalization extends beyond simply inserting a first name—it allows you to tailor entire messages based on what you know about each customer.

Dynamic email content uses custom property values to customize message elements for each recipient. Using Klaviyo’s template language, you can insert custom property values directly into your content using the syntax {{ person|lookup:'Property Name' }}. This approach allows you to reference any custom property stored on the customer’s profile, creating truly personalized communications.

Conditional content takes personalization further by showing or hiding entire content blocks based on custom property values. For example, you might show different product recommendations to customers based on their stored preferences, or include special offers only for subscribers who meet certain criteria. This conditional approach ensures each recipient sees content relevant to their specific interests and situation.

Advanced Personalization Techniques

Taking personalization beyond basic variable insertion creates truly distinctive experiences that make customers feel understood and valued. These advanced techniques leverage custom properties to create sophisticated, tailored communications.

Default values ensure your personalized content always displays properly, even when custom property data is missing:

• Use Klaviyo’s default filter: {{ person|lookup:'Favorite Color'|default:'blue' }}
• Create logical fallbacks based on available data
• Develop content that works regardless of whether specific properties exist
• Test your templates with profiles missing various properties

Content variations based on multiple properties create highly tailored experiences:

1. Combine demographic and preference data to create targeted product recommendations
2. Adjust messaging tone based on customer characteristics and past interactions
3. Modify offers and incentives according to customer value and purchase history
4. Customize imagery and examples to reflect customer interests and demographics

Testing and optimization processes help refine your personalization strategy over time:

• A/B test different personalization approaches to identify what resonates best
• Monitor engagement metrics for personalized versus generic content
• Gradually increase personalization complexity as you validate simpler approaches
• Regularly review custom property data quality to ensure personalization accuracy

Leveraging Custom Properties in Automated Flows

Automated flows become significantly more powerful when enhanced with custom property data. By incorporating these properties into your flow conditions, content, and logic, you create sophisticated automation that responds intelligently to each customer’s unique characteristics.

Flow triggers based on custom properties allow you to initiate automated sequences when specific conditions are met. For example, you might trigger a flow when a birthday date property indicates an upcoming birthday, when a subscription status changes, or when a customer reaches a certain loyalty point threshold. These property-based triggers create timely, relevant automation opportunities beyond standard behavioral triggers.

Flow filters using custom properties ensure that only appropriate customers proceed through your automated sequences. You might use filters to exclude customers with certain preferences, to target only those in specific geographic regions, or to customize flow paths based on stored customer attributes. These filters help prevent sending irrelevant content while ensuring each customer receives the most appropriate messaging.

Creating Sophisticated Multi-Path Flows

Multi-path flows that branch based on custom property values create personalized customer journeys that adapt to individual characteristics. This approach allows you to create a single flow structure that delivers different experiences to different customer segments.

Conditional splits direct customers down different paths based on their custom property values:

• Split based on preference properties to deliver category-specific content
• Create different paths for different customer value tiers
• Develop separate journeys based on customer lifecycle stage
• Customize follow-up sequences based on survey responses or preferences

Dynamic waiting periods adjust timing based on customer attributes:

1. Vary communication frequency based on stated preferences
2. Adjust follow-up timing according to customer engagement history
3. Create different urgency levels based on customer characteristics
4. Customize reminder sequences based on past response patterns

Content customization within flows ensures each message feels personally relevant:

• Dynamically insert custom property values into flow emails
• Show different product recommendations based on stored preferences
• Adjust offers and incentives according to customer value
• Customize imagery and examples to match customer demographics

Measuring and Optimizing Custom Property Performance

To maximize the value of your custom properties, establish systems for measuring their impact and continuously improving your approach. Regular analysis helps identify which properties drive the most significant improvements in your marketing performance.

Tracking campaign performance by segment reveals how different custom property-based audiences respond to your marketing. Compare open rates, click-through rates, conversion rates, and revenue generated across different segments to identify which customer groups engage most effectively with your content. This analysis helps prioritize your marketing efforts toward the most responsive and valuable segments.

Analyzing property completion rates helps identify gaps in your customer data. Regularly audit what percentage of your profiles have each custom property populated, and look for patterns in missing data. Low completion rates might indicate problems with your data collection methods or opportunities to implement new collection strategies for valuable but underutilized properties.

Continuous Improvement Strategies

Implementing a systematic approach to custom property optimization ensures your data strategy evolves alongside your business and customer needs. Regular review and refinement keep your custom properties aligned with your marketing objectives.

Data quality audits help maintain the integrity and usefulness of your custom property data:

• Review properties for inconsistent formatting or unexpected values
• Identify and merge duplicate properties that capture similar information
• Archive obsolete properties that no longer serve your marketing strategy
• Standardize values for properties with free-form text inputs

Property utilization assessment identifies opportunities to better leverage your existing data:

1. Evaluate which properties you actively use in segments, flows, and content
2. Identify valuable properties with low utilization in your marketing
3. Discover properties with high completion rates but minimal marketing application
4. Determine which properties most strongly correlate with customer engagement

Expansion planning helps evolve your custom property strategy to address emerging needs:

• Identify gaps in your current customer data that limit marketing effectiveness
• Develop collection strategies for new properties that would enhance personalization
• Prioritize new properties based on their potential marketing impact
• Create implementation plans that minimize disruption to existing systems

Take Your Klaviyo Marketing to the Next Level

Custom properties transform standard email marketing into sophisticated, personalized customer journeys that drive engagement and conversions. By thoughtfully implementing and managing these properties, you create a robust foundation for targeted segmentation, dynamic content, and automated flows that respond intelligently to each customer’s unique characteristics and behaviors.

The most successful Klaviyo marketers approach custom properties strategically, focusing on collecting and utilizing the data that most significantly impacts marketing performance. Start with a core set of high-value properties aligned with your business objectives, then gradually expand as you validate their effectiveness and identify new opportunities. Remember that quality matters more than quantity—a few well-maintained, highly-utilized properties provide more value than dozens of incomplete or unused data points.

Your custom property strategy should evolve alongside your business and customer relationships. Regularly review your approach, measuring which properties drive meaningful improvements in engagement and conversion rates. Clean and update your data to maintain accuracy, and don’t hesitate to archive properties that no longer serve your needs. With thoughtful implementation and ongoing optimization, custom properties become powerful assets that continuously enhance your Klaviyo marketing effectiveness.