# Customize namespaces

When exposing an API to users, grouping API methods into namespaces creates an object-oriented SDK interface. This type of interface helps users better conceptualize the objects they are manipulating when using the API.

## Default Behavior

By default, Speakeasy uses the `tags` in the OpenAPI spec as organizing principles for namespaces. For each `tag` in the spec, Speakeasy creates a namespace.

Each method will then be added to namespaces corresponding with its `tags`. If a method does not have an associated `tag`, it will be added to the root SDK class of the generated client library. If a method has multiple tags associated with it, the operation will appear as a method in multiple classes.

The following example illustrates the method `sdk.Drinks.ListDrinks()` assigned to the `Drinks` namespace and another method `sdk.ListLocations()` kept in the default class:

```yaml filename="Tags"
paths:
  /bar_locations:
    get:
    operationId: listLocations
    summary: List all locations of the Speakeasy bar
    description: Get a list of all the bars being run by Speakeasy
    responses:
      "200":
        description: A list of bars
        content:
          application/json:
            schema:
              type: array
              items:
                $ref: "#/components/schemas/BarLocation"
  /drinks:
    get:
      operationId: listDrinks
      summary: List all drinks
      description: Get a list of all drinks served by the bar
      tags:
        - drinks
      responses:
        "200":
          description: A list of drinks
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: "#/components/schemas/Drink"
tags:
  - name: drinks
    description: Everything about our Drinks on offer
```

The generated SDK will include methods that can be invoked as follows:

```go
// Method added into the Drinks namespace
sdk.Drinks.ListDrinks()
// Default method
sdk.ListLocations()
```

## Define Namespaces Without Tags `x-speakeasy-group`

Sometimes the `tags` in an OpenAPI spec may already be used for an unrelated purpose (for example, autogenerating documentation). In this scenario, using something other than `tags` to organize methods may be necessary.

The `x-speakeasy-group` field allows defining custom namespaces. Add this field to any operation in the OpenAPI spec to override any `tags` associated with that method. For example:

```yaml filename="x-speakeasy-group"
paths:
  /drinks/{drink_type}/get_vintage:
    get:
      operationId: getVintage
      summary: Check the vintage of the wine
      description: Get the vintage of a drink served by the bar
      parameters:
        - name: drink_type
          in: path
          description: The type of drink
          required: true
          schema:
            type: string
      tags:
        - drinks
      x-speakeasy-group: wine
      responses:
        "200":
          description: A list of drinks
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: "#/components/schemas/Drink"
tags:
  - name: drinks
    description: Everything about Drinks on offer
```

The generated SDK will include a method, which can be invoked as follows:

```go
// GetVintage - get the vintage of the wine
sdk.wine.GetVintage("wine")
```

## Define Multi-Level Namespaces

Use `tags` or the `x-speakeasy-group` extension to define nested namespaces for operations using `.` notation. There is no limit to the number of levels that can be defined.

The generated SDK will include a method, invoked as follows:

```go
// Get the Vintage of a specified wine.
sdk.Drinks.Wine.GetVintage("wine")
```

## Multiple Namespaces

If you want to add a method to multiple namespaces, list multiple values in `tags` or the `x-speakeasy-group` extension. Both accept an array of values:

The generated SDK will include methods that can be invoked as follows:

```go
// Get the Vintage
sdk.Drinks.GetVintage("wine")
sdk.Wine.GetVintage("wine")
```