I haven't tried that one properly, but in the modern software world, I tend to shy away from anything that's not in active development. COW was last updated more than a year ago, and features like "compare your openings to games on chess.com" will either not get developed, or if they are, start breaking over time... We kind of expect these modern tools and integrations etc now. I'm finding that after the initial effort getting each variation in, chessable spaced repition is really easy, and I can use on any device, wherever I am.... but it's still not ideal.
Best way to record your opening repertoire?

Hi,
You may have a look at https://chess-repertoire-companion.com
It's free, online and under development.
Chessbase online has a repertoire feature which also lets you practice moves. The downside is that it's partitioned as a black repertoire and a white repertoire, which is not very convenient if you want to practice something specific, eg a subset of your black repertoire.
It does come with advantages though, It's accessible from anywhere, any device and you can filter games from their live DB from your repertoire.

On Android, Chess Openings Trainer Lite can be used for free. It is simple and just fine to store a repertoire with all variations, and it includes a stockfish engine. There is a training mode too.

I found this thread because I was looking for a tool to store and practice all the lines I learn in my favourite youtube video's (*cough* Gotham *cough*). I couldn't find anything satisfying until I heard of this new thing: www.pawndojo.com. It seems a bit rough, but they are doing tiny updates every few days.
I used it to repeat some lines in my car right before each game in my first OTB tournament last month. Helped me a lot!
A few months ago I stumbled across this thread. Since then I have been developing a (free) tool myself. You can import your already existing repertoire or start a new one and can display all of your different lines at once to get a feeling for the size or zoom in and add new moves and color/comment them.
It has implemented stockfish engine, lichess database with win ratios and can handle transpositions. For anyone who still stumbles across this old thread: It's called www.treevis.org
Hope it helps you!

I think this tool might help you: https://chessflare.com/en

A few months ago I stumbled across this thread. Since then I have been developing a (free) tool myself. You can import your already existing repertoire or start a new one and can display all of your different lines at once to get a feeling for the size or zoom in and add new moves and color/comment them.
It has implemented stockfish engine, lichess database with win ratios and can handle transpositions. For anyone who still stumbles across this old thread: It's called www.treevis.org
Hope it helps you!
cool tool. thanks
I like Chess Openings Wizard. It handles transpositions well - no matter how you get to a position, it flows into whatever your moves are from that point. It also lets you write notes. If, for example, you like two different answers to a position, you can annotate "GM so-and-so plays xx, while GM whoever plays yy. I prefer ..." and your tree can follow each line. It also has a training mode that lets you practice your repertoire. Many more features - and easy to use.