Bits of .NET

Many devs see slow API responses and blame SQL, not realizing the slowdown is Mapper.

⚠ The Problem

AutoMapper uses reflection for complex object graphs.
Under load → becomes slow.

✔ Life-Saver Solution

Switch to compiled mapping:

var config = new MapperConfiguration(cfg =>
{
    cfg.CreateMap<User, UserDto>().ConvertUsing(src =>
        new UserDto(src.Id, src.Name));
});

or write your own mapping:

public UserDto Map(User u) =>
    new(u.Id, u.Name);

⚡ Result

• Up to 10× faster mapping

• Massive CPU drop