Sepolia RPC Endpoint:

https://rpc.sepolia.dev

You can also use the following RPC nodes too:

https://rpc.sepolia.org/

https://rpc2.sepolia.org/ 

https://rpc.sepolia.online/

https://www.sepoliarpc.space/

https://rpc-sepolia.rockx.com/

https://rpc.bordel.wtf/sepolia