On Squirrel Beta, you can swap on Ropsten and all mainnets. Only a handful of tokens have been added to our Beta app, but note that the swaps are real. This is to say that if you import a wallet and then make a swap on a mainnet (e.g. BSC), that swap is as permanent as it would be on any other live service. If you wish to test without swapping any real tokens, please stay on Ropsten!