# Configuration

### How to configure

Swagger-UI accepts configuration parameters in four locations.

From lowest to highest precedence:
- The `swagger-config.yaml` in the project root directory, if it exists, is baked into the application
- configuration object passed as an argument to Swagger-UI (`SwaggerUI({ ... })`)
- configuration document fetched from a specified `configUrl`
- configuration items passed as key/value pairs in the URL query string


### Parameters

Parameters with dots in their names are single strings used to organize subordinate parameters, and are not indicative of a nested structure.

For readability, parameters are grouped by category and sorted alphabetically.

Type notations are formatted like so:
- `String=""` means a String type with a default value of `""`.
- `String=["a"*, "b", "c", "d"]` means a String type that can be `a`, `b`, `c`, or `d`, with the `*` indicating that `a` is the default value.

##### Core

Parameter Name | Description
--- | ---
`configUrl` | `String`. URL to fetch external configuration document from.
`dom_id` |`String`, **REQUIRED** if `domNode` is not provided. The id of a dom element inside which SwaggerUi will put the user interface for swagger.
`domNode` | `Element`, **REQUIRED** if `dom_id` is not provided. The HTML DOM element inside which SwaggerUi will put the user interface for swagger. Overrides `dom_id`.
`spec` | `Object={}`. A JS object describing the OpenAPI Specification. When used, the `url` parameter will not be parsed. This is useful for testing manually-generated specifications without hosting them.
`url` | `String`. The url pointing to API definition (normally `swagger.json` or `swagger.yaml`). Will be ignored if `urls` or `spec` is used.
`urls` | `String`. An array of API definition objects (`{url: "<url>", name: "<name>"}`) used by Topbar plugin. When used and Topbar plugin is enabled, the `url` parameter will not be parsed. Names and URLs must be unique among all items in this array, since they're used as identifiers.
`urls.primaryName` | `String`. When using `urls`, you can use this subparameter. If the value matches the name of a spec provided in `urls`, that spec will be displayed when Swagger-UI loads, instead of defaulting to the first spec in `urls`.

##### Plugin system

Read more about the plugin system in the [Customization documentation](/docs/customization/overview.md).

Parameter Name | Description
--- | ---
`layout` | `String="BaseLayout"`. The name of a component available via the plugin system to use as the top-level layout for Swagger-UI.
`plugins` | `Array=[]`. An array of plugin functions to use in Swagger-UI.
`presets` | `Array=[SwaggerUI.presets.ApisPreset]`. An array of presets to use in Swagger-UI. Usually, you'll want to include `ApisPreset` if you use this option.

##### Display

Parameter Name | Description
--- | ---
`deepLinking` | `Boolean=false`. If set to `true`, enables deep linking for tags and operations. See the [Deep Linking documentation](/docs/usage/deep-linking.md) for more information.
`displayOperationId` | `Boolean=false`. Controls the display of operationId in operations list. The default is `false`.
`defaultModelsExpandDepth` | `Number=1`. The default expansion depth for models (set to -1 completely hide the models).
`defaultModelExpandDepth` | `Number=1`. The default expansion depth for the model on the model-example section.
`defaultModelRendering` | `String=["example"*, "model"]`. Controls how the model is shown when the API is first rendered. (The user can always switch the rendering for a given model by clicking the 'Model' and 'Example Value' links.)
`displayRequestDuration` | `Boolean=false`. Controls the display of the request duration (in milliseconds) for Try-It-Out requests.
`docExpansion` | `String=["list"*, "full", "none"]`. Controls the default expansion setting for the operations and tags. It can be 'list' (expands only the tags), 'full' (expands the tags and operations) or 'none' (expands nothing).
`filter` | `Boolean=false OR String`. If set, enables filtering. The top bar will show an edit box that you can use to filter the tagged operations that are shown. Can be Boolean to enable or disable, or a string, in which case filtering will be enabled using that string as the filter expression. Filtering is case sensitive matching the filter expression anywhere inside the tag.
`maxDisplayedTags` | `Number`. If set, limits the number of tagged operations displayed to at most this many. The default is to show all operations.
`operationsSorter` | `Function=(a => a)`. Apply a sort to the operation list of each API. It can be 'alpha' (sort by paths alphanumerically), 'method' (sort by HTTP method) or a function (see Array.prototype.sort() to know how sort function works). Default is the order returned by the server unchanged.
`showExtensions` | `Boolean=false`. Controls the display of vendor extension (`x-`) fields and values for Operations, Parameters, and Schema.
`tagsSorter` | `Function=(a => a)`. Apply a sort to the tag list of each API. It can be 'alpha' (sort by paths alphanumerically) or a function (see [Array.prototype.sort()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort) to learn how to write a sort function). Two tag name strings are passed to the sorter for each pass. Default is the order determined by Swagger-UI.

##### Network

Parameter Name | Description
--- | ---
`oauth2RedirectUrl` | `String`. OAuth redirect URL.
`requestInterceptor` | `Function=(a => a)`. MUST be a function.  Function to intercept remote definition, Try-It-Out, and OAuth2 requests.  Accepts one argument requestInterceptor(request) and must return the potentially modified request.
`responseInterceptor` |`Function=(a => a)`. MUST be a function.  Function to intercept remote definition, Try-It-Out, and OAuth2 responses.  Accepts one argument responseInterceptor(response) and must return the potentially modified response.
`showMutatedRequest` | `Boolean=true`. If set to `true`, uses the mutated request returned from a requestInterceptor to produce the curl command in the UI, otherwise the request before the requestInterceptor was applied is used.
`validatorUrl` | `String="https://online.swagger.io/validator" OR null`. By default, Swagger-UI attempts to validate specs against swagger.io's online validator. You can use this parameter to set a different validator URL, for example for locally deployed validators ([Validator Badge](https://github.com/swagger-api/validator-badge)). Setting it to `null` will disable validation.

##### Macros

Parameter Name | Description
--- | ---
`modelPropertyMacro` | `Function`. Function to set default values to each property in model. Accepts one argument modelPropertyMacro(property), property is immutable
`parameterMacro` | `Function`. Function to set default value to parameters. Accepts two arguments parameterMacro(operation, parameter). Operation and parameter are objects passed for context, both remain immutable
