According to https://support.biteasy.com/kb/rest-api/endpoints/transactions-hash there is a field "object" which contains the hex of the transaction. This doesn't seem to exist though. Example: look at the output of https://api.biteasy.com/v2/btc/testnet/transactions/4586e67ee5adcdbc97ed3d2a026ee8703df2ed3553854c186c216e90cd761b69