How i can get price tickers from dex in all chains?

Hello, I want to create an arbitrage screener for dex exchangers, how can I get price tickers for pairs of tokens in different networks? I have an idea that you need to get them under the contract, but I think itโ€™s pretty trivial. Maybe there are some aggregators or api for easy work with this?

you may need real time data from the chain (like processing the transactions as fast as possible with a node), or even from mem pool transactions in order to have as much information as possible