Repeater Fields: Lists Inside Records

Not everything in a business record is a single value. An invoice has multiple line items. A project has multiple milestones. An order has multiple products. A supplier has multiple contact people.

These are lists embedded inside a parent record — not separate objects related by a foreign key, but inline collections that belong entirely to the parent.

Repeater fields handle this pattern directly.

A List That Lives in the Record

A repeater field is a list of structured items, each with the same set of sub-fields. Define the structure of one item — description, quantity, unit price, VAT rate, for an invoice line — and the repeater manages a collection of those items on the parent record.

In the form, the repeater shows each existing item with all its sub-fields editable inline. An "Add item" button appends a new empty item. Items can be reordered by dragging their handles. Individual items can be removed.

Calculated Totals

Repeater fields can include computed sub-fields that calculate values from other sub-fields within the same item. A line item's total price can be automatically calculated as quantity multiplied by unit price — updated in real time as either value changes.

Parent-level computed fields can aggregate across all repeater items. Invoice total calculates from the sum of all line item totals. The arithmetic is automatic; users enter the source values and see the results.

Full Validation Within Items

Each sub-field in a repeater item can be individually validated. Quantities must be positive numbers. Descriptions are required. Unit prices can't be zero. Validation runs per-item and shows errors in context — next to the specific sub-field in the specific item that failed.

Submitting a form with any invalid repeater item is blocked, with clear indication of which items need attention.

Common Use Cases

Invoice and order line items — the canonical repeater use case. Products, quantities, prices, and discounts for each line.

Task checklists — a list of sub-tasks with completion status and optional due dates, nested inside a project task.

Contact methods — multiple phone numbers or email addresses for a contact, each with a type label (mobile, work, billing contact, etc.).

Milestones and phases — sequential stages for a project with names, dates, and status.

Any data that naturally forms a repeated structure with consistent fields belongs in a repeater. The form handles the list management; you focus on the content.