MufidSuica cards are so fast.. my local transit card is not this fast.
I bet all transactions are local and there is no servers communication. I guess, no server validation is fine in Japan as they are high trust society?
Fuchsiii~~~@mufid @LunaDragofelis Suica stores the money you put in on the card itself along with 1,3 or 6 month prepaid fair tickets. so yes no servers required. Germany once had a similar system called GiroGo that was discontinued because no one (except the cafeteria at my sisters school) used it.
Kevin Karhan 
@fuchsiii @mufid @LunaDragofelis you mean #GeldKarte?
And yes, the card being updated after every transaction and basically doing a cryptographic balance / credit check and/or storing the transaction and values until at a terminal is the way these work.