Yes, deriv is legit but the source of their legitimacy is weak. Let me explain, deriv got their operational licenses from some low tier regulators, they are regulated by:
1. Saint Vincent & Grenadines - weak regulator
2. FSC British Virgin Islnds - weak regulator
3. Malta FSC - weak regulator
4. Labuan FSA - moderate reguator
Now, although deriv is legit because they have about 4 operational licenses, you will notice these licenses are not from well-known reguators like those ones in the United Kingdom, Australia, Germany etc. This is why i saw deriv has weak regulation.
Most of these weal regulators are located in island countries whose governments are just interested in generating revenue through licensing various brokers. These island nation governments do not have proper structures on ground to monitor these forex broker operations overseas.
So, to summarize deriv is legit but I would not deposit a huge sum of money with them I would only deposit what i want to trade with and withdraw it after that.