# Searching by custom fields
Source: https://docs.mambu.com/api/pages/api-v2/searching-by-custom-fields

# Searching by custom fields

> Search for entries where the given custom field definition has the value `FALSE`

```json
{
  "filterCriteria": [
    {
      "field": "_marketing_opt_in.investor_newsletter",
      "operator": "EQUALS_CASE_SENSITIVE",
      "value": "FALSE"
    }
  ]
}
```

> Search for entries where the given custom field definition has one of the given values, sort by ID

```json
{
  "filterCriteria": [
    {
      "field": "_group_details.industry",
      "operator": "IN",
      "values": [
        "agriculture",
        "arboriculture"
      ]
    }
  ],
  "sortingCriteria": {
    "field": "id",
    "order": "ASC"
  }
}
```

You can build your filter and search queries using the native fields enumerated in the relevant schemas, for more information, see [Searching for Records](/api/pages/api-v2/searching-for-records). However, you can also use custom field definitions and their values in your filter and search queries for any entities that support custom field definitions. For more information, see [Custom Fields](/docs/custom-fields) in our User Guide.

To filter or sort using a custom field definition you must provide the custom field set ID and the custom field definition ID using dot nation, for example `_custom_field_set_ID.custom_field_ID`. You can see an example of the syntax to the right. The custom field set can belong to the same entity or to a parent entity.