What Are Salesforce Custom Objects?
Salesforce custom objects are database tables created to store organization-specific data beyond standard objects like Contacts, Leads, Accounts, and Opportunities. According to Salesforce custom object documentation, custom objects can represent any business entity—members, patients, students, properties, subscriptions, or any data unique to your business. The Salesforce Trailhead data modeling module explains that custom objects carry all the functionality of standard objects, including fields, relationships, page layouts, and automation support, while allowing organizations to define data structures that match their specific operational needs.
Common custom objects used in email marketing include membership records for gyms, associations, and clubs; patient or client records in healthcare and professional services; student and applicant records in education; subscriber and registration objects for SaaS platforms; event attendee and session records; property and listing records in real estate; and custom relationship objects that connect standard records in unique ways. These objects often contain the email addresses and segmentation data that organizations need for targeted, relevant marketing campaigns.
Mailchimp’s Custom Object Limitations
The standard Mailchimp-Salesforce integration has significant custom object limitations that affect how organizations can use their CRM data for email marketing. According to Mailchimp’s Salesforce customization documentation, the integration focuses on displaying Mailchimp data against Lead and Contact layouts—it does not provide mechanisms for syncing custom object data into Mailchimp audiences.
No Direct Custom Object Sync: Mailchimp’s integration primarily syncs Contacts and Leads. Custom objects don’t sync directly to Mailchimp audiences, meaning any data stored in custom objects—membership status, enrollment records, property details—remains invisible to Mailchimp’s email marketing tools.
Limited Field Access: Even with workarounds, custom object fields don’t map to Mailchimp merge fields without manual processes. This restricts the personalization data available for email content, limiting campaigns to only the standard fields that exist on Contact and Lead records.
No Custom Object Segmentation: Organizations cannot build Mailchimp segments based on custom object criteria or relationships. A membership organization, for example, cannot create a segment of members with expiring memberships if that data lives in a custom Membership object.
Relationship Data Lost: Parent-child relationships and lookups between custom objects and standard objects don’t transfer through the integration. The relational context that makes Salesforce data powerful for targeted marketing is stripped away during synchronization.
No Custom Object Triggers: Mailchimp automations cannot be triggered based on custom object record changes. When a membership expires, a student enrolls, or a property status changes, these events cannot automatically initiate email sequences through the Mailchimp integration.
Common Workarounds and Their Problems
Organizations attempt various workarounds to bridge the custom object gap, but each introduces its own complications that compound over time.
Formula Fields: Creating formula fields on Contact or Lead records to pull custom object data is the most common approach. However, formula field complexity is limited by Salesforce’s character limits, the data only refreshes when the formula recalculates, and proliferating formula fields clutters Contact records with data that belongs elsewhere in the data model.
Flow Builder Automation: Using Salesforce Flow Builder to copy custom object data to Contact fields provides more flexibility than formulas but introduces maintenance overhead. Flows must be updated whenever custom object structures change, timing issues can cause data staleness between sync cycles, and debugging flow failures across interconnected automations becomes increasingly complex.
Third-Party Middleware: Tools like Zapier or custom API integrations add another system layer between Salesforce and Mailchimp. While more capable than formula fields, middleware introduces additional subscription costs, creates another potential point of failure, and requires dedicated technical resources for monitoring and maintenance.
Manual Exports: Exporting custom object data and importing it to Mailchimp is the simplest approach but the least scalable. The process is time-consuming, error-prone, and data becomes outdated immediately after each export. For organizations sending frequent campaigns, manual exports create an unsustainable workflow.
These workarounds add complexity without fully solving the underlying limitation—they approximate custom object access rather than providing genuine integration with the complete Salesforce data model.
Impact on Email Campaigns
Custom object limitations affect email campaigns across every stage of the email marketing workflow, from audience selection through performance analysis.
Segmentation: Organizations cannot target audiences based on custom object criteria. A healthcare provider cannot easily email patients with upcoming appointments if appointment data lives in a custom object. A membership organization cannot segment by membership tier, renewal date, or activity level stored in custom Membership records.
Personalization: Without custom object field access, email templates cannot merge custom object data into personalized content. This limits relevance—a real estate agent cannot include specific property details in listing alert emails, and an education institution cannot reference specific program or enrollment information in student communications.
Automation: Organizations cannot trigger email automation or drip campaigns based on custom object changes. When a membership renews, a student completes a course module, or a property status changes, these events cannot automatically launch relevant email sequences through the Mailchimp integration.
Sequences and Follow-ups: Email sequences and follow-up sequences cannot respond to custom object events, preventing organizations from building behavior-driven communication workflows based on their most important business data.
Reporting: Engagement data doesn’t flow back to custom objects for tracking and analysis. Organizations lose the ability to measure email performance in the context of their custom data model—they cannot easily correlate email engagement with membership renewals, patient outcomes, or enrollment conversions.
Industries Most Affected
Custom object limitations particularly impact industries that rely on specialized data models for their core operations. Membership organizations—gyms, clubs, professional associations—typically store member data in custom Membership objects that track dues, renewal dates, and activity levels. Healthcare providers use custom objects for patient management, including appointments, care plans, and compliance tracking. Educational institutions maintain custom objects for students, applicants, enrollments, and academic programs. Real estate firms track properties, listings, buyer preferences, and showing schedules in custom objects. Event management companies use custom objects for registrations, attendees, sessions, and venue details. Financial services firms rely on custom objects for portfolios, holdings, and client relationship structures. In each case, the most important data for targeted email marketing lives in custom objects that Mailchimp’s standard integration cannot access.
Native Solutions with Full Custom Object Support
Unlike external platforms requiring sync, native Salesforce email solutions access any Salesforce object directly. The Mailchimp Salesforce integration by Beaufort 12 attempts to bridge this gap with advanced mapping capabilities, but organizations seeking seamless custom object access often find native solutions more effective. For a detailed comparison, see MassMailer vs Mailchimp. Native solutions provide several key advantages:
Direct Custom Object Access: Send emails directly from any custom object—no sync, no workarounds. Any object with an email field becomes a valid email recipient, whether it’s a Member, Patient, Student, Property, or any other custom record.
Full Field Availability: Use any custom object field in templates, merge fields, and personalization. Every field on the custom object is available for dynamic content insertion without requiring field mapping or formula field workarounds.
Relationship Support: Access parent-child relationships, lookups, and related contact list data. The full relational power of Salesforce’s data model is available for segmentation and personalization, preserving the context that makes targeted email marketing effective.
Custom Object Triggers: Launch triggered emails based on custom object record creation or field changes. When a membership expires, a patient appointment is scheduled, or a property status updates, automated email sequences can fire immediately.
Engagement on Custom Objects: Track email engagement data directly on custom object records. Opens, clicks, bounces, and unsubscribes appear on the records that matter most to your business operations.
Enabling Custom Objects for Email
With native Salesforce solutions, enabling custom objects for email marketing is straightforward. For step-by-step instructions, see our guide on how to enable custom objects in MassMailer. The process typically involves enabling the custom object in app settings, specifying the email field on the custom object, configuring opt-out field mapping to ensure compliance, setting up templates with custom object merge fields for personalization, and building list views or reports for audience targeting. Once configured, the custom object functions as a first-class email recipient just like standard Contacts and Leads.
Benefits of Native Custom Object Support
No Sync Delays: Use current custom object data instantly—no waiting for external sync cycles to complete. When a record changes in Salesforce, that change is immediately available for email targeting and personalization.
Real-Time Engagement: View email analytics and engagement metrics, including open rates on custom object records, immediately after delivery. This enables rapid response to engagement signals without waiting for cross-platform data synchronization.
Better Deliverability: Accurate, current data improves email deliverability. Native solutions eliminate stale sync data that causes bounces, since email addresses are validated directly from the source records at send time rather than from a synchronized copy that may be hours or days old.
Simplified Compliance: Unsubscribe and opt-out status on custom objects is respected instantly—no sync delay compliance risks. When a recipient opts out, that preference takes effect immediately across all future sends from that custom object.
No Workarounds: Eliminate formula fields, flows, and middleware just to access your own data. Native custom object support removes the entire workaround layer, reducing maintenance overhead and eliminating potential failure points in the email marketing workflow.
Mass Email from Custom Objects
Native solutions enable mass email directly from custom objects. Unlike Mailchimp, which only syncs Contacts and Leads, native apps can send to any object with an email field. This overcomes Salesforce’s 5,000 daily email limit while maintaining full custom object access. Use email verification to ensure custom object email addresses are valid before sending, reducing bounces and protecting sender reputation.
Native Salesforce Solution
For organizations needing full custom object support, MassMailer operates 100% native to Salesforce with complete custom object capabilities. Send from any object, use any field, track engagement directly on records. Full email integration with your entire Salesforce data model—no sync required, no workarounds needed.
Key Takeaways
- Mailchimp-Salesforce integration has limited custom object support—primarily syncs Contacts and Leads
- Workarounds like formula fields and middleware add complexity without fully solving limitations
- Native Salesforce solutions access any custom object directly—no sync required
- Industries using custom objects (membership, healthcare, education) benefit most from native solutions
Need full custom object support? MassMailer delivers email marketing from any Salesforce object—custom or standard. Use the email builder with full custom object field access. Get best-in-class capabilities without integration limitations.
