Bundata Docs
Primitive types Nested objects Arrays When to use which type Validation and constraints Reference Next steps

Field types

Schema fields in Schema Studio support a set of field types that define how extracted content is structured in your smart bites. Choosing the right type improves extraction confidence and makes output usable for the Vector Catalog, RAG, and agents.

Primitive types

TypeUse forExample
TextTitles, body text, names, free-form stringstitle, body, vendor_name
NumberQuantities, amounts, page numberstotal, quantity, page_number
DateEffective date, due date, signing dateeffective_date, invoice_date
BooleanFlags (e.g. signed, confidential)is_signed, has_amendments

Use text for any string that isn’t strictly numeric or date; use number and date when you need filtering or validation downstream.

Nested objects

Use object for a single structured block (e.g. one address, one party block):

  • Address — { "line1", "city", "postal_code", "country" }
  • Party — { "name", "role", "contact" }

Nested objects keep related fields together and preserve source lineage at the parent level.

Arrays

Use array for repeated items:

  • Line items — line_items[] with description, quantity, amount
  • Sections — sections[] with title, content
  • Signatories — signatories[] with name, date

Array elements can be primitives (e.g. list of strings) or objects. Arrays are common for invoices, contracts (sections, parties), and policy documents.

When to use which type

  • Contracts — Text for clauses and body; date for effective/termination; object or array for parties and sections.
  • Invoices — Number for totals and quantities; date for invoice/due date; array of objects for line items.
  • Policy docs — Text for sections; optional metadata (version, effective date) as date or text.

See Schema design for minimal schema examples.

Validation and constraints

  • Required vs. optional — Mark fields required only when they always exist; otherwise optional reduces run failures. See Schema design.
  • Format hints — Where supported (e.g. date format), use them so parsing is consistent across documents.

Reference

For the full list of types and constraints supported in the API and UI, see Schema field reference.

Next steps

Previous
Schema design