How to add authentication (JWT) in Swagger.md

Problem

How to add authentication i.e JWT in Swagger?

Environment

Visual Studio, Asp.Net Core 6, C#

How you fix it

Installing the Swashbuckle, Microsoft.AspNetCore.Authentication.JwtBearer package and add the following custom code in the program.cs.

Solution

Installing packages

Install the required packages from the Nuget Package Manager or by simply running these commands in Package Manager Console.

dotnet add package Swashbuckle.AspNetCore
dotnet add package Microsoft.AspNetCore.Authentication.JwtBearer

Add the following code in Program.cs file

This code will help to enable authetication layer in the Swagger.

builder.Services.AddSwaggerGen(options => {
options.AddSecurityDefinition("oauth2", new OpenApiSecurityScheme{ 
        Description = "Authentication using Bearer Scheme (\"bearer {token}\")",
        In = ParameterLocation.Header,
        Name = "Authorization",
        Type = SecuritySchemeType.ApiKey
});
    options.OperationFilter<SecurityRequirementsOperationFilter>();
});

Now add the following code in Program.cs file

This code will take API key from the AppSettings, help to generate JWT.

builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
    .AddJwtBearer(options =>
    {
        options.TokenValidationParameters = new TokenValidationParameters
        {
            ValidateIssuerSigningKey = true,
            IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8
            .GetBytes(builder.Configuration.GetSection("AppSettings:Token").Value)),
            ValidateIssuer = false,
            ValidateAudience = false   

        };
    });

Fianlly add these lines in the following order in the end of Program.cs file

app.UseAuthentication();

app.UseAuthorization();

Run Application

Now run the application, you will be able to see lock sign in the top of swagger API. put the jwt token in this format 'Bearer "your JWT Token"'.