じゃあ
Although you probably know さようなら (sayounara) is “goodbye,” it has a very strong sense of finality, almost like you may not see that person again. So it’s often better to say じゃまた. Other variations are じゃね (ja ne: “see you”), バイバイ (baibai: “bye-bye”), and お元気で (o-genki de: “take care”).
Source: https://www.fluentin3months.com/japanese-words/