In some examples, a system may use content classes to manage indexing of object data. A content class may include a set of one or more content properties. Each content property may include a name, an expression for extracting data, and an expression type. When object data is received, such as for indexing, the expression type of each content property may be compared with the data type of the received data. Based at least in part on determining that the expression type matches the data type, the system may extract a data value from the received data in accordance with the expression. The system may save the extracted data value to a data structure in association with the name of the content property, and may subsequently use the data value and the name of the content property when creating an index for the object data.