Before .NET 10, enabling strict validation Deserialization

Program.cs

using System.Text.Json;
using System.Text.Json.Serialization;

var options = new JsonSerializerOptions
{
    AllowDuplicateProperties = false,
    UnmappedMemberHandling = JsonUnmappedMemberHandling.Disallow,
    PropertyNameCaseInsensitive = false,
    RespectNullableAnnotations = true,
    RespectRequiredConstructorParameters = true
};
var user = JsonSerializer.Deserialize<LoginRequest>(jsonPayload, options);