Decoder rhymes with:
coder, boeder, broder, coder, fodor, froder, fyodor, loader, loder, lowder, moder, oder, odor, roder, roeder, schroader, schroder, schroeder, soder, soeder, sowder, stroder, yoder
Decoder sounds like:
daughter, daughtery, daughtrey, daughtry, dauster, decastro, decatur, decoster, decter, degutare, desiderio, destroy, destroyer, detector, dexter, dextra, dextro, dichter, dictator, digester, disaster, dockstader, dockter, doctor, doktor, doster, doxtater, duster, dykstra