How soon is too soon to be exchanging numbers on a dating app?

It’s been 2 days of chatting back and forth, but this one guy recommended moving to another app like whatsapp. I feel it’s too soon, so I suggested other forms of social media first, but he insisted he is more active there. What do you think is the right thing to do?
Updates
11 mo
He apologised for asking and said whatever you’re comfortable with. Seems sweet, I’ll give it a few more days and then decide.
How soon is too soon to be exchanging numbers on a dating app?
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