# Authenticating > The authentication system for the UiPath Orchestrator API uses a bearer token for local users and NTLM authentication for directory users. The authentication system for the UiPath Orchestrator API uses a bearer token for local users and NTLM authentication for directory users. :::note By default, the bearer token expires after 30 minutes. ::: :::important The instructions on this page apply only for the on-premises Orchestrator API. Basic authentication for API is not supported for Automation Cloud Orchestrator tenants. If you are using the Orchestrator service in Automation Cloud, use the instructions in [Consuming Cloud API](https://docs.uipath.com/orchestrator/automation-cloud/latest/api-guide/getting-the-api-access-information-from-the-automation-clouds-ui) instead. ::: ## Local User Authentication Via a Bearer Token 1. Make a **POST** request to the `{OrchestratorURL}/api/account/authenticate` endpoint with your Orchestrator login credentials, as in the example below. POST `{OrchestratorURL}/api/account/authenticate` **Request headers:** | Key | Value | | --- | --- | | Authorization | Bearer | **Request body:** ``` { "tenancyName" : "Documentation", "usernameOrEmailAddress" : "Documentation", "password" : "DocumentationAPItest" } ``` ****Response code:** 200 OK** **Response body:** ``` { "result": "", "targetUrl": null, "success": true, "error": null, "unAuthorizedRequest": false, "__abp": true } ``` 2. Copy the string in the result parameter of the HTTP response to the Clipboard. This represents the bearer token and can be used in all future requests as follows: * As an **Authorization** header with the `Bearer xxxxxxxxxxxxx` value, where `xxxxxxxxxxxxx` represents the string previously copied; * If your API testing tool supports it, select the bearer token authorization type and input the string previously copied. ## Domain User Authentication Via NTLM Authentication :::important To authenticate your requests using Windows credentials you need to use an API client that supports NTLM authentication, such as [Postman](https://learning.postman.com/docs/sending-requests/authorization/#ntlm-authentication). ::: 1. Make a request to the desired endpoint specifying your Windows credentials in the dedicated API client. To change an NTLM auth header in Postman, navigate to the **Auth** tab, set the **Type** to **NTLM Authentication**, and fill in the **Username** and **Password** fields. ![docs image](https://dev-assets.cms.uipath.com/assets/images/orchestrator/orchestrator-219793-429b7352.webp) 2. If your user exists in multiple tenants, specify the exact one using the `X-UIPATH-TenantName` header otherwise the request is performed in the first tenant the user has been provisioned in. The following example illustrates a `GET` request to the `{OrchestratorURL}/odata/Processes` endpoint in the Finance tenant. GET `{OrchestratorURL}/odata/Processes` **Request headers:** | Key | Value | | --- | --- | | Authorization | Bearer | | X-UIPATH-TenantName | The name of the tenant.For example, "Finance". | ****Response code:** 200 OK** **Response body:** ``` { "@odata.context": "{OrchestratorURL}/odata/$metadata#Processes", "@odata.count": 2, "value": [ { "IsActive": false, "SupportsMultipleEntryPoints": false, "RequiresUserInteraction": true, "Title": null, "Version": "1.0.6981.35861", "Key": "QueueItemsProcessing:1.0.6981.35861", "Description": "Process items from an Orchestrator queue.", "Published": "2020-10-17T14:22:11.0566667Z", "IsLatestVersion": false, "OldVersion": null, "ReleaseNotes": null, "Authors": "petrina.smith", "ProjectType": "Undefined", "Id": "QueueItemsProcessing", "Arguments": { "Input": "[{\"name\":\"argument1\",\"type\":\"System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089\",\"required\":false,\"hasDefault\":true},{\"name\":\"argument2\",\"type\":\"System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089\",\"required\":false,\"hasDefault\":false},{\"name\":\"argument3\",\"type\":\"System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089\",\"required\":false,\"hasDefault\":true}]", "Output": null } }, { "IsActive": false, "SupportsMultipleEntryPoints": false, "RequiresUserInteraction": false, "Title": "TestingSequence", "Version": "4.0.6", "Key": "TestingSequence:4.0.6", "Description": "Blank Process", "Published": "2020-10-17T13:04:06.6766667Z", "IsLatestVersion": false, "OldVersion": null, "ReleaseNotes": "Invoke WF Action Generator", "Authors": "petrina.smith", "ProjectType": "Process", "Id": "TestingSequence", "Arguments": { "Input": "[{\"name\":\"Name\",\"type\":\"System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089\",\"required\":false,\"hasDefault\":false},{\"name\":\"Email\",\"type\":\"System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089\",\"required\":false,\"hasDefault\":false},{\"name\":\"Product\",\"type\":\"System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089\",\"required\":false,\"hasDefault\":false}]", "Output": null } } ] } ``` ## Accessing Swagger If you are using Swagger to try our API, just log in to your Orchestrator instance in a separate tab. The Orchestrator API Swagger definition can be accessed by adding the `/swagger/ui/index#/` suffix to your Orchestrator URL. For example, {baseURL2} `/swagger/ui/index#/`. :::note The Swagger authentication expires according to the parameters set in your Orchestrator instance. By default, it is set to 30 minutes. You can change it by modifying the value of the `Auth.Cookie.Expire` parameter, in the `Web.config` file. :::