you should use multiple API options then because all block explorers could go down or have some sort of problem. but having an alternative to fall back to in case one was down is a better option. blockcypher has good APIs that you could use Blockonomics also is good that supports SegWit addresses too.

there is another (safer) option which is to use Electrum servers instead of a block explorer. take a look at the protocol here: https://electrumx.readthedocs.io/en/latest/