Whats the difference between doxycycline and amoxicillin?

Whats the difference between doxycycline and amoxicillin?
They are two different families of antibiotics and they treat different things. Sometimes they can be interchanged but amoxicillin is used for greatly of ear nose and throat ailments while doxycycline is used to treat acne and some bacterial std's. One is within the tetracycline drug family and the other is contained by the penicillin drug family.
both are antibiotics, both are correctly broad spectrum, the doxycycline tends to be somewhat stronger than the amoxicillin, and can be deeply harder on the stomach.
well i did some research and they are anitbiotics. doxycycline is simply stronger!!