Online casinos ensure the integrity and fairness of their slot games through several key practices. They utilize Random Number Generators (RNGs) to guarantee that the outcomes of games are random and unbiased, which is crucial for maintaining fairness in gameplay. Additionally, reputable online casinos are licensed and regulated by authoritative bodies, which impose strict standards for game testing and transparency. Independent testing agencies often audit the games to verify that they meet these standards, further assuring players of their reliability.