Fields¶

Declare a Python annotation and assign a Mongoz field factory. Pydantic owns model validation; Mongoz adds persistence and query metadata.

Field	Python-facing value	Stored/BSON role
`String`	`str`	String; length, pattern, choices, index metadata.
`Email`	`str`	Email-validated string.
`Integer`	`int`	Integer with optional numeric bounds.
`Double`	`float`	Floating-point number with optional bounds.
`Decimal`	`decimal.Decimal`	Converted through BSON `Decimal128`.
`Boolean`	`bool`	Boolean.
`DateTime`	`datetime.datetime`	BSON datetime; supports automatic timestamps.
`Date`	`datetime.date`	Date-oriented validated value.
`Time`	`datetime.time`	Time-oriented validated value.
`UUID`	`uuid.UUID`	UUID value using BSON-compatible encoding.
`Binary`	`bytes`	Binary data with optional length bound.
`Object`	`dict`	JSON-like mapping.
`ObjectId`	BSON-compatible identifier	Required object identifier value.
`NullableObjectId`	identifier or `None`	Nullable identifier field.
`Array(T)`	`list[T]`	Typed array.
`ArrayList`	`list`	Dynamically typed list.
`Embed(T)`	embedded model	Nested `EmbeddedDocument`.
`ForeignKey(T)`	related identifier/document metadata	Reference to another document collection.

Shared options¶

Availability varies by field kind. Invalid combinations raise FieldDefinitionError or Pydantic validation errors.

Option	Contract
`default`	Default value ownership. A callable is invoked per instance.
`null`	Whether `None` is accepted. Keep the Python annotation compatible.
`alias`	Stored/model key mapping.
`read_only`	Model metadata only; not request authorization.
`index`, `unique`	Adds desired index metadata; does not perform import-time I/O.
`choices`	Restricts values to declared choices.
`min_length`, `max_length`	Bounds strings, arrays, or binary values where supported.
`minimum`, `maximum`	Bounds numeric values.
`auto_now`, `auto_now_add`	Automatic date/datetime update or creation values.

Use model_fields and Pydantic schema output for programmatic introspection. Avoid relying on private field implementation classes.