Many months ago, I was researching about the best chess website in existence. I came across two competitors, both of which I am sure you have all heard of before - Chess.com and Lichess. While I did find some discussions around this, most notably on Quora, ichess.net and chessable.com, after many months of using both platforms, I found these answers pretty incomplete, so I would like to put in my two cents to this debate.
Disclaimer: This post is not sponsored or endorsed by Chess.com or Lichess. The differences between Chess.com and Lichess identified in this post are primarily based on their respective iOS mobile apps, but most differences should be applicable on the website as well.
General Consensus
Here, I summarise the things that many people have said in various forums online.
Commercial vs Open Source
Perhaps the biggest difference between the two platforms is that while Chess.com is a commercial business, Lichess is an open-source non-profit. This means all the features on Lichess are completely free of charge, compared to Chess.com where many features are behind a paywall. The cheapest plan costs $2.42/month, so this is definitely something to consider. This also means that there are many advertisements for a Premium account on Chess.com, compared to literally none on Lichess. Technically, you can support Lichess by becoming a patron and donating a certain sum of your own choosing, but the only tangible benefit you will receive is a cool profile icon.
The other consequence of this is that for the developers out there, Lichess has its own API that you can use to interact with your own profile and more. You can submit code on their GitHub page as well!
Rating Discrepancies - while both platforms are generally inflated upwards, meaning that your FIDE rating is most likely lower than your Chess.com or Lichess rating, most people agree that your Chess.com rating is closer to your actual FIDE rating than your Lichess rating. Personally, I do not have a FIDE rating, but my Lichess rating is higher than my Chess.com rating, so this appears to be true in my case.
Engine Analysis Categories - in Lichess, your moves are categorised as "inaccuracy", "mistake", "blunder" or nothing, i.e. it does not tell you anything about how good your moves were. On the other hand, Chess.com categorises all of your moves as "Brilliant", "Best", "Excellent", "Good", "Book", "Inaccuracy", "Mistake", "Blunder" and "Missed Win", so you know how good your moves were. Two unique move categories are "Book" and "Missed Win". "Book" refers to a standard move in opening books, and "Missed Win" is a failure to punish your opponent's blunder - a mate in X, winning material or gaining a positional advantage. Lichess will classify such moves simply as a blunder.
User Interface - the general consensus seems to be that Chess.com's UI sucks, and I couldn't agree less. Whereas Lichess's UI is sleek and intuitive, Chess.com looks outdated and is very hard to find the things I want. Trust me, some of you may be thinking that the UI doesn't matter, but it really does make me not want to play as much on Chess.com.
My Own Comments
These are some of the more subtle differences that you may not notice but could greatly affect your gameplay/experience using the platforms.
Multiple Premoves - this is a feature that is only available in Chess.com, and is quite important for people who like to play bullet and blitz games. If, for example, you have a straight path for your passed pawn and you would just like to keep pushing it, you can premove it all the way. On Lichess, this is not possible - you can only premove once, and must wait for the opponent to play in order to premove again.
Selecting a Piece whilst Premoving - let's say you're playing a typical Queen's gambit position as white, and you have already played Nf3 and e3, preparing to castle short. If the opponent takes the pawn, you would like to retake the pawn with Bxf4. Otherwise, you would like to play Be2 so that you can castle. On Lichess, you can premove Bxf4, and still select the bishop and hold it over e2 so that you can immediately play Be2, if the opponent doesn't take the pawn. This might seem very trivial, but believe me, it is extremely irritating when you try to do this on Chess.com, because touching another piece whilst you have a premove will actually cancel the premove.
Accessibility - in addition to xiangqi, @StevenOh and I like to play chess variants like crazy house, antichess and more. Although I have an account on both Chess.com and Lichess, he does not. The fact that you can play anonymously on Lichess without signing up by sending a link to the chess game is extremely useful compared to Chess.com, where you are forced to sign up to play a game.
30 seconds before first move - in Lichess, both White and Black has 30 seconds to make their first move before the game is automatically aborted. During this time period, the chess clock does not officially start.In Chess.com, there are no such waiting periods, so as soon as White plays his or her move, Black's clock starts. Personally, I prefer Lichess's waiting period as it allows me to consider White's first move and take time to choose my opening when I am black, but on the flip side, some people may find it irritating when the opponent takes ages to make their first move.
Toxic Users - this is a purely subjective observation, but I've personally never received an offensive message from any user on Lichess, but I have received some from Chess.com users on several occasions. Below is a screenshot of a conversation that took place on September 1st, 2020.
After I won a 3 min blitz game, my opponent BlackBurne16 was being very toxic.
If this is something that upsets you, consider playing on Lichess instead.
Conclusion
Although I started playing chess on Chess.com, I now only play on Lichess. It has free analysis, there are no advertisements, I can play with my friend @StevenOh and it comforts me knowing that I can work with their API in the future if I come up with a good project idea. For me, the only benefit of playing on Chess.com is their 4 player chess variant. Of course, if you're willing to spend a little to improve your chess skills, then Chess.com will definitely be better for you since they have tons of educational videos and lessons. Although the Lichess interface may be harder to get used to compared to Chess.com, my advice for any beginners out there would be to try both and choose your "main" platform. Playing on both means that you have fewer games on each one, so it's harder to see a trend in your progress over time. With that said, go checkmate someone!
I like programming (Python, Java and some frontend), chess, xiangqi, maths, puzzles and more. You can find me on Chess.com @SoySoy4444. I'm always up for a challenge!