SWAP BETWEEN DIFFERENTS CRYPTO

PERSONAL WALLET:
Hello Cardano world.

I develope a cardano wallet and I would like to know how could I swap my ada between different cryptos like etherium, binance, Solana, Polygon, etc. It’s been very hard to me to find documentation.
I don’t even know how to start, do I need a blockchain node from each crypto I want to swap to, or don’t?
If someome can help me to find some source code where i can reference to or some docs I would be very glad.