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Custom Fields Template for Product Planning
A structured template for specifying custom fields infrastructure in SaaS products. Covers field types, validation rules, schema management, API...
Updated 2026-03-05
Custom Fields
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Frequently Asked Questions
How many custom fields should we support per entity?+
30-50 per entity is the sweet spot. Below 30, power users feel constrained. Above 50, the UI becomes overwhelming and JSONB storage performance degrades. If customers need more than 50 fields, they likely need a custom integration or a more specialized tool. Track actual usage. Most customers use 5-15 custom fields.
Should custom fields be available via the API?+
Yes. Custom field data must be readable and writable via the same entity API endpoints as built-in fields. A separate custom fields API is acceptable for field management (creating/updating field definitions), but the data itself must travel with the entity. See the [Enterprise Feature Request Template](/templates/enterprise-feature-request-template) for how to evaluate API extensibility requests.
How do custom fields interact with import/export?+
Custom fields appear as columns in CSV exports and can be populated during CSV imports. The import mapping step must show custom fields alongside built-in fields. For exports, include a "Custom Fields" section in column configuration so users can select which custom fields to include. The [Data Import Template](/templates/data-import-template) covers the full import workflow including custom field mapping.
Should custom field definitions be shared across organizations in a multi-tenant setup?+
No. Custom field definitions are per-organization. Each customer defines their own fields. For products with a multi-org hierarchy (parent org + child orgs), you may offer "inherited" field definitions that propagate from parent to child, but child orgs should be able to override or add their own. See the [Multi-Tenant Design Template](/templates/multi-tenant-design-template) for multi-org configuration patterns. ---
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