nteresting question, below is my own opinion on this:
there are a few things to unfold;
Is trading in crypto currency gambling or a ‘legit investment’ ?
Are you borrowing money from someone (including leverage on brokerage sites) to make these trades?
And lastly a bit of an easy one; Are you checking your trades or doing trades on Shabbat?
The latter is of course not allowed, and im not talking about the prohibition of building that is often use to disallow the usage of electronic devices on shabbat, but more specifically money changing hands or doing things not in the spirit of shabbat (since even if you don’t trade but simply see how these trades are doing mean you are doing work; crypto markets are 24/7)
Are you borrowing money from someone? Borrowing money with interest (which would be the case for basically any loan you take) is not allowed if the person you
are lending it to is a Jew, or to receive a loan with interest from a Jew if you’re a Jew. It’s often extremely difficult to find out who exactly owns (majority) stake
in the brokerage sites you’re using, so I think most would stay on the safe side and say you should outright not use leverage on your trades.
Is Trading crypto currency gambling? Although not forbidden, gambling is looked down upon in the talmud as it would make you untrustworthy (‘disqualified to be a witness in court’) and is seen as a wasteful activity.
There are many arguments on whether or not trading crypto, or stocks for that matter, can be seen as gambling. Personally I think it can be gambling, but well researched investments, even if risky, would not be gambling. I would compare it to playing darts, there was once a story about a court case in the UK where a pub
got sued for having a dartboard in his establishment, ‘games of chance’ were forbidden at that time, the owner however argued that it was not a game of chance and
rather a sport. Meaning that if you practice more you will be able to more consistently hit the most advantageous shots. To prove his point he asked for a dartboard to be placed in the court and threw 3 darts in the triple 20 section and invited anyone in that court to try and match his perfect score. The case was dropped afterwards.
Crypto trading can be gambling if you’re not using skill to make trades, but blindly follow random opinions on the internet etc.