In order to maintain simplicity, PicoOPC reduces its model to just a handful of types.

The types listed in the table below are data objects. They do not perform any operations besides manipulating in-memory data. The data objects are all defined as immutable.

Type Name	Description
AttributeId	Identifiers assigned to attributes.
BuiltInType	Enumeration of built-in types.
DataValue	The value and associated information.
NodeId	Unambiguously identifies a node.
NodeIdType	Type of the node ID identifier.
ReadValueId	Identifier for an item to read.
Variant	A union of all built-in data types.
WriteValue	Describes a node, and its attribute and value.

There is one service object type, i.e. a type that allows the actual operations on the target system.

Type Name	Description
Client	A minimalistic OPC UA client object.

The actual representation of the types depends on the language binding.