Hey all

In April I'll be traveling to Singapore. I got invited to visit family in Hongkong, so I had to adjust my plans a little bit (hopping over for a few days, then head back to Singapore)
I'll be arriving around midnight at SIN and my onward flight to HKG leaves at 6am that morning.
Since there won't be any public transport running at those hours, my only option would be getting into town (and back) by cab or booking a room in a transit hotel. Both options would completely wreck my student travel budget.
Is it also possible to just stay airside at SIN overnight?
I'm traveling two different airlines, but I won't have any checked luggage with me. I could just check in online and try to get comfy on some chairs airside, before my scheduled morning flight leaves.

Would that be a possibility, or do I have to clear immigration and wait it out landside?

Thank you very much in advance