What would be the best way to get for example all the txs on a certain smart contract in the past 24h? I assume using middleware would be the way to go?
/middleware/contracts/transactions/address/CONTRACT_ADDRESS is the endpoint of middleware you are looking for
is this endpoint also available remotely, or it is necessary to run a full node?
I don’t understand the question, currently the middleware is separate from the node, there is a hosted version available, e.g. https://mainnet.aeternal.io/middleware/contracts/transactions/address/ct_ouZib4wT9cNwgRA1pxgA63XEUd8eQRrG8PcePDEYogBc1VYTq
How about getting the tx after a payable function executes?
if you get the tx hash in return you can then query it directly from the node using the sdks or api