Firework by Katy Perry is in Db at 126 beats per minute and runs 3:14 across 56 bars. It uses 7 chords — Ab, Gb, Fm, Db, Bbm7, Fm7, Eb. The chord diagram changes as the song plays and the words light up as they are sung, so you can strum and sing along without reading ahead.
Want the melody line note by note? Firework guitar melody tab.