# ID Types

You can use [`id_types`]({{< ref "profiles/concepts/id.md" >}}) to list the type of identifiers used in an ID stitcher. You can also use this parameter for creating `entity_var` and `input_var`. The data type of these identifiers must be `string`.

```yaml
id_types:
  - name: user_id
    filters:
      - type: include/exclude
        value: "value"
      - type: include/exclude
        regex: "regex expression"
  - name: email
    maximum_edges:
      - user_id: 1
```

| Field | Description |
| :-------------- | :---- |
| `name` <br/> <span style="color: #4D4DFF;font-size:12px;">Required</span> | Name of the ID type. |
| `filters` | Filter(s) the ID types to include/exclude specific values. The filters are processed in the listed order.  |
| `maximum_edges` | Defines cardinality rules that limit how many connections a node of an ID type can have to another node of other ID types. |
| `type` | Filter type - accepted values are `include` or `exclude`. |
| `value` | Specify the value that should be matched exactly. |
| `regex` | Regular expression to match. |
  
## Example

```yaml
entities:
  - name: user
    id_column_name: user_rud_id
    id_types:
      - user_id
      - anonymous_id
      - email

id_types:
  - name: user_id
    maximum_edges:
      - email: 2
      - anonymous_id: 5
  - name: anonymous_id
    extends: user_id
    filters:
      - type: exclude
        value: "unknown"
      - type: exclude
        value: "NaN"
  - name: email
    filters:
      - type: include
        regex: "[A-Za-z0-9+_.-]+@(.+)"
```