Custom Fields - Store Any Data, Personalize Everything | SMASHSEND

[ ![SMASHSEND email marketing - The #1 Email Marketing Tool that turns emails into revenue](https://smashsend.com/_next/static/media/smashsend_dark.da05b6ec.svg) ![SMASHSEND email marketing - The #1 Email Marketing Tool that turns emails into revenue](https://smashsend.com/_next/static/media/smashsend_dark.da05b6ec.svg) ](https://smashsend.com/) Features Integrations & API Resources 1.  [        Home        ](https://smashsend.com/) / 3.  [        Custom Fields        ](https://smashsend.com/custom-fields) Go beyond basic contact info. With SMASHSEND Custom Fields, track any data that matters to your business — from shoe sizes to subscription tiers, purchase history to preferences. Unlimited custom fields · All data types supported · API access included E-commerce fieldsMulti-select `favorite_categories`\["Electronics", "Fashion"\] `lifetime_value`$2,450.00 `last_purchase_date`2024-03-15 `preferred_size`Large SaaS propertiesNumber `api_calls_this_month`45,291 `team_members`12 `storage_used_gb`28.5 `feature_adoption_score`87% ## The most flexible custom fields in email marketing While others limit you to basic fields, SMASHSEND gives you the power to store any data type, create complex properties, and use them everywhere. ∞ Unlimited fields 10+ Data types 0ms Real-time sync ## Every data type you need ### Text & numbers Store names, descriptions, IDs, scores, prices, quantities, or any text and numeric data. Perfect for basic customer information and metrics. ### Lists & arrays Track multiple values like product interests, tags, categories, or preferences. Use single-select or multi-select options for structured data. ### Dates & booleans Capture timestamps, anniversaries, expiration dates, or yes/no flags. Perfect for time-based automations and conditional logic. ### JSON objects Store complex nested data structures for advanced use cases. Perfect for developers who need maximum flexibility. ### Encrypted fields Store sensitive data securely with field-level encryption. Perfect for PII, tokens, or any confidential information. ### Computed fields Create dynamic fields that calculate values based on other properties. Update automatically as source data changes. ## Use custom fields everywhere Your custom fields aren't locked away — use them across the entire SMASHSEND platform for truly personalized experiences. ### In email campaigns Personalize every email with custom field tokens. Display customer-specific data, recommendations, or dynamic content based on any property. ### In segmentation Build powerful segments using any custom field. Combine multiple conditions with AND/OR logic to target exactly the right audience. ### In automations Trigger workflows based on custom field changes. Update fields automatically, create conditional branches, or sync with external systems. ### Via API & webhooks Full API access to read and write custom fields. Receive webhooks when fields change. Keep your entire stack in sync. ## Personalize with field tokens Reference any property directly in your campaign copy. ```Hi {{first_name}}, Based on your preference for {{favorite_category}},we thought you'd love our new collection! Your loyalty points: {{loyalty_points}}Member since: {{member_since}}``` ## Real-world use cases See how businesses use SMASHSEND Custom Fields to create powerful, data-driven email experiences. E-commerce ### Personalization that uses real history Track purchase history, browsing behavior, size preferences, and wish list items, then target recommendations off those fields. Targeted product recommendations convert 3x better. SaaS ### Onboarding driven by adoption Monitor feature adoption, usage metrics, and subscription details, and trigger onboarding emails from user behavior and progress. Every onboarding email matches where the user actually is. Education ### Courses that respond to progress Track course progress, quiz scores, and learning preferences to send content recommendations and achievement celebrations. Learners get the next step, not the same newsletter. Healthcare ### Compliant, personal reminders Store appointment history, preferences, and consent data securely with field-level encryption. HIPAA-compliant reminders and personalized health tips. Real estate ### Match leads to listings Track property preferences, budget ranges, and viewing history so the right listing reaches the right lead. Leads matched with properties automatically. Gaming ### Player-aware messaging Store player stats, achievements, and preferences to drive game updates, rewards, and recommendations. Updates that reflect how each player actually plays. ## SMASHSEND vs. limited field systems Most email platforms limit you to basic fields. See why developers and marketers choose SMASHSEND for true flexibility. Feature SMASHSEND Others Number of custom fields Unlimited 10-50 fields Data types supported All types + JSON Text & numbers only Array/list support Native support Not supported API access Full CRUD API Limited or paid Field validation Custom validators Basic only Pricing Included free Premium add-on ## Developer-friendly integration Built by developers, for developers. Integrate custom fields with your application in minutes, not days. ```// Create a custom fieldconst field = await smashsend.customFields.create({  name: 'subscription_tier',  type: 'select',  options: ['free', 'pro', 'enterprise'],  defaultValue: 'free'}); // Update contact with custom fieldawait smashsend.contacts.update('ctc_abc123', {  email: 'user@example.com',  properties: {    subscription_tier: 'pro',    last_login: new Date(),    feature_flags: ['dark_mode', 'beta_access'],    usage_stats: {      api_calls: 1523,      storage_gb: 12.5    }  }});``` ## Part of the complete SMASHSEND platform Custom fields work seamlessly with every SMASHSEND feature. One platform, infinite possibilities. ## Start building with custom fields today Join thousands of businesses using SMASHSEND Custom Fields to create truly personalized email experiences. Unlimited fields • All data types • Full API access • Free forever