In bitcoin addresses can start with a 1, 3, or bech. And in Ethereum, it starts with 0x. Does Solana have a specific format to their addresses? Or is it just the base58 output with nothing added in?
No specific format
But you can generate Vanity Addresses
Also is a public and private key a specific length? I measured public address is 44 characters and private key is 87 characters. Is this always the same?
Yes