Field data types

The system data types a layer field can declare, and the JSON value each one expects. layer-detail reports a field's type as a numeric dataType; every value you send on create or update must match it.

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System data types

Data type	dataType	Send as	Rules
Yes/No (Boolean)	1	Boolean
Number	2	Integer
String	3	String
Real	4	Number	Decimals allowed
Date	5	String	ISO 8601, e.g. 2026-09-07T09:30:00Z
Big String	6	String	Longer free text, including multi-line
Map	7	String	GeoJSON geometry serialized to a string
Document	8	String	Multi-line text containing HTML tags
List	10	String	An allowed list value - see below

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List fields

A field of type List (dataType 10) accepts only the values its definition allows, and you send the stored value, not the display label. There are two kinds:

• Enum - the values are defined on the field itself. On the demo SAMPLE_DATA layer, sample_data_option accepts 1 (Option A) or 2 (Option B).
• Layer-backed - the values come from another layer. sample_data_state, sample_data_district and sample_data_sub_district read from ADMINISTRATIVE and take an AdministrativeID.

Dependent lists must form a valid chain: district must belong to the state you sent, and sub-district to that district. Sending an unrelated ID is rejected.

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Used by

• Custom Data Layers API