> For the complete documentation index, see [llms.txt](https://docs.n8n.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.n8n.io/connect/create-nodes/build-your-node/reference/credentials-files.md).

# Credentials files

The credentials file defines the authorization methods for the node. The settings in this file affect what n8n displays in the **Credentials** modal, and must reflect the authentication requirements of the service you're connecting to.

In the credentials file, you can use all the [n8n UI elements](/connect/create-nodes/build-your-node/reference/node-ui-elements.md). n8n encrypts the data that's stored using credentials using an encryption key.

## Structure of the credentials file <a href="#structure-of-the-credentials-file" id="structure-of-the-credentials-file"></a>

The credentials file follows this basic structure:

1. Import statements
2. Create a class for the credentials
3. Within the class, define the properties that control authentication for the node.

### Outline structure <a href="#outline-structure" id="outline-structure"></a>

```js
import {
	IAuthenticateGeneric,
	ICredentialTestRequest,
	ICredentialType,
	INodeProperties,
} from 'n8n-workflow';

export class ExampleNode implements ICredentialType {
	name = 'exampleNodeApi';
	displayName = 'Example Node API';
	documentationUrl = '';
	properties: INodeProperties[] = [
		{
			displayName: 'API Key',
			name: 'apiKey',
			type: 'string',
			default: '',
		},
	];
	authenticate: IAuthenticateGeneric = {
		type: 'generic',
		properties: {
    		// Can be body, header, qs or auth
			qs: {
        		// Use the value from `apiKey` above
				'api_key': '={{$credentials.apiKey}}'
			}

		},
	};
	test: ICredentialTestRequest = {
		request: {
			baseURL: '={{$credentials?.domain}}',
			url: '/bearer',
		},
	};
}
```

## Parameters <a href="#parameters" id="parameters"></a>

### `name` <a href="#name" id="name"></a>

String. The internal name of the object. Used to reference it from other places in the node.

### `displayName` <a href="#displayname" id="displayname"></a>

String. The name n8n uses in the GUI.

### `documentationUrl` <a href="#documentationurl" id="documentationurl"></a>

String. URL to your credentials documentation.

### `properties` <a href="#properties" id="properties"></a>

Each object contains:

* `displayName`: the name n8n uses in the GUI.
* `name`: the internal name of the object. Used to reference it from other places in the node.
* `type`: the data type expected, such as `string`.
* `default`: the URL that n8n should use to test credentials.

### `authenticate` <a href="#authenticate" id="authenticate"></a>

* `authenticate`: Object. Contains objects that tell n8n how to inject the authentication data as part of the API request.

#### `type` <a href="#type" id="type"></a>

String. If you're using an authentication method that sends data in the header, body, or query string, set this to `'generic'`.

#### `properties` <a href="#properties" id="properties"></a>

Object. Defines the authentication methods. Options are:

* `body`: Object. Sends authentication data in the request body. Can contain nested objects.

```typescript
authenticate: IAuthenticateGeneric = {
	type: 'generic',
	properties: {
		body: {
			username: '={{$credentials.username}}',
			password: '={{$credentials.password}}',
		},
	},
};
```

* `header`: Object. Send authentication data in the request header.

```typescript
authenticate: IAuthenticateGeneric = {
	type: 'generic',
	properties: {
		header: {
			Authorization: '=Bearer {{$credentials.authToken}}',
		},
	},
};
```

* `qs`: Object. Stands for "query string." Send authentication data in the request query string.

```typescript
authenticate: IAuthenticateGeneric = {
	type: 'generic',
	properties: {
		qs: {
			token: '={{$credentials.token}}',
		},
	},
};
```

* `auth`: Object. Used for Basic Auth. Requires `username` and `password` as the key names.

```typescript
authenticate: IAuthenticateGeneric = {
	type: 'generic',
	properties: {
		auth: {
			username: '={{$credentials.username}}',
			password: '={{$credentials.password}}',
		},
	},
};
```

### `test` <a href="#test" id="test"></a>

Provide a `request` object containing a URL and authentication type that n8n can use to test the credential.

```typescript
test: ICredentialTestRequest = {
		request: {
			baseURL: '={{$credentials?.domain}}',
			url: '/bearer',
		},
	};
```