Is there any way to expose Sitecore Api? So that 3rd party application can use POST request and further sitecore application can manage POST request

Yes you can do it by creating an API controller. So for this you need to follow these steps.

• Create a controller and inherit it from ApiController

  namespace Feature.ExampleApi.Controllers { public class ExampleApiController : ApiController { [HttpPost] [Route("post/{itemNameString}")] public IHttpActionResult CreateItem(string itemNameString) { // Do your operation // Do sth with item return Json(result); } } } 

• Register your controller

  namespace Feature.ExampleApi { public class ServicesConfigurator : IServicesConfigurator { public void Configure(IServiceCollection serviceCollection) { // Controllers serviceCollection.Replace(ServiceDescriptor.Transient(typeof(ExampleApiController), typeof(ExampleApiController))); } } } 

  If you are working with headless environment, register it like this.

  public void Configure(IServiceCollection serviceCollection) { serviceCollection.AddScoped<IDefaultRenderingContentsResolver, DefaultRenderingContentsResolver>(); serviceCollection.AddMvcControllers("*.Feature"); } 

  Follow this article for headless environment.

  https://trnktms.com/2022/09/29/sitecore-headless-how-to-reuse-layout-service-serialization-in-custom-api-controllers/

• Create config.

  <configuration xmlns:patch="http://www.sitecore.net/xmlconfig/"> <sitecore> <services> <configurator type="Feature.ExampleApi.ServicesConfigurator, Feature.ExampleApi" /> </services> </sitecore> </configuration> 

Follow this article for more details.

https://jakubwajs.wordpress.com/2020/06/21/create-api-controller-in-sitecore-9-3/

You can also work with the Sitecore Item Serice to create items and more.

https://doc.sitecore.com/xp/en/developers/92/sitecore-experience-manager/the-restful-api-for-the-itemservice.html