Karabiner - Switch | (pipe) and \ (backslash) keys

private.xml

<?xml version="1.0"?>
<root>

  <item>
    <name>Swap \ and | keys.</name>
    <identifier>private.swap_backslash_and_pipe</identifier>

    <autogen>
      __KeyToKey__
      KeyCode::BACKSLASH, ModifierFlag::NONE,
      KeyCode::BACKSLASH, ModifierFlag::SHIFT_L,
    </autogen>

    <autogen>
      __KeyToKey__
      KeyCode::BACKSLASH, MODIFIERFLAG_EITHER_LEFT_OR_RIGHT_SHIFT | ModifierFlag::NONE,
      KeyCode::BACKSLASH,
    </autogen>
  </item>

</root>