Introduction: In the realm of modern APIs, the provision of clear and comprehensive documentation plays a pivotal role in facilitating developer adoption and ensuring efficient utilization. Swagger, aligned with the OpenAPI Initiative, stands out as a prominent solution, offering machine-readable documentation and a user-friendly interactive interface. In this guide, we'll delve into the seamless integration of Swagger into your .NET Core API. Step 1: Install the necessary packages Add Swashbuckle.AspNetCore NuGet package to a project: dotnet add package Swashbuckle.AspNetCore Add Swashbuckle.AspNetCore.SwaggerUI NuGet package to a project: dotnet add package Swashbuckle.AspNetCore.SwaggerUI Step 2: Add services in program.cs In the program.cs file, include the following service additions: builder.Services.AddEndpointsApiExplorer(); builder.Services.AddSwaggerGen(); Additionally, add middleware in program.cs to enable Swagger in the development environment:   if (app.Environment.IsDevelopment()) { app.UseSwagger(); app.UseSwaggerUI(); } Step 3: Run the API project and access the Swagger UI at: https://your-api-base-url/swagger Ensure the API project is running, and navigate to the provided URL to explore and interact with the Swagger UI seamlessly. Step 3:  Execute the APIs and test.