it depends on how you play
what's Duo's Elo?

nothing except Stockfish beats Duo
Me who beated Duo the second it came out with no help: >: )
when i beat duo before he came out

i played the rossolimo i won esaily but i think if i have played a language opening it would been harder

I just beat him, I've probably tried around 10 to 15 times, I got a draw before, but now came my first victory. I think it is somewhere between 2000 and 2400...

Is it just me or Duolingo robots are a little rude when they "chat" (I know it's just programmed responses, but it still hurts)
I am an 1800 and I beat him with ease. It has many flaws such as taking out its queen early in the opening and making many small mistakes in the endgame. In my opinion, it is around 1500 Elo.