An even more casual form of 'to iu ka', used in speech/text to correct or rephrase—functions like 'or rather' / 'I mean'. Very common in colloquial Japanese.
彼、暇なの？ってか忙しくないんだっけ？
Is he free? I mean, isn't he busy?
行きたくない、ってか今日は体調が悪いんだ。
I don't want to go—actually, I'm feeling unwell today.
いいね、ってかその色すごく似合ってるよ。
Nice—actually, that color suits you really well.