Program.cs

using System.Text;
using AspnetCoreJwt.Models;
using AspnetCoreJwt.Services;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;
using Microsoft.IdentityModel.Tokens;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
builder.Services.AddMvc();
builder.Services.AddTransient<IAuthService, AuthService>();

// Database Context
builder.Services.AddDbContext<ApplicationDbContext>(options => options.UseSqlite("Data Source=AspNetCoreJwt.db"));

// Identity  
builder.Services
       .AddIdentity<ApplicationUser, IdentityRole>()
       .AddEntityFrameworkStores<ApplicationDbContext>()
       .AddDefaultTokenProviders();

// Authentication
builder.Services.AddAuthentication(options =>
{
    options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
    options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
    options.DefaultScheme = JwtBearerDefaults.AuthenticationScheme;
})
.AddJwtBearer(options =>
{
    options.SaveToken = true;
    options.RequireHttpsMetadata = false;
    options.TokenValidationParameters = new TokenValidationParameters
    {
        ValidateIssuer = true,
        ValidateAudience = true,
        ValidAudience = builder.Configuration["JWT:ValidAudience"],
        ValidIssuer = builder.Configuration["JWT:ValidIssuer"],
        ClockSkew = TimeSpan.Zero,
        IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(builder.Configuration["JWT:Secret"]))
    };
}
);

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    // app.UseSwaggerUI();
    // new Line
    app.UseSwaggerUI(opt =>
    {
        opt.SwaggerEndpoint("/swagger/v1/swagger.json", "v1");
        opt.RoutePrefix = string.Empty;
    });
}
app.UseHttpsRedirection();
app.UseAuthentication();
app.UseAuthorization();
app.MapControllers();
app.Run();