[Home](./index.md) > [ibm-cloud-sdk-core](./ibm-cloud-sdk-core.md) > [BearerTokenAuthenticator](./ibm-cloud-sdk-core.bearertokenauthenticator.md) > [authenticate](./ibm-cloud-sdk-core.bearertokenauthenticator.authenticate.md) ## BearerTokenAuthenticator.authenticate() method Add a bearer token to `requestOptions`. The bearer token information will be set in the Authorization property of "requestOptions.headers" in the form: Authorization: Bearer <bearer-token> **Signature:** ```typescript authenticate(requestOptions: AuthenticateOptions): Promise; ``` ## Parameters

Parameter	Type	Description
requestOptions	AuthenticateOptions	The request to augment with authentication information.

**Returns:** Promise<void>