# Working with User Defined Fields/Custom Fields

* [about-udfs-custom-fields-and-udts](https://help.claritylims.illumina.com/api-and-database/api-docs/cookbook/working-with-user-defined-fields-custom-fields/about-udfs-custom-fields-and-udts "mention")
* [performing-post-step-calculations-with-custom-fields-udfs](https://help.claritylims.illumina.com/api-and-database/api-docs/cookbook/working-with-user-defined-fields-custom-fields/performing-post-step-calculations-with-custom-fields-udfs "mention")