The Hardest Part by Coldplay is in Eb at 124 beats per minute and runs 3:54 across 55 bars. It uses 10 chords — Eb, Gm, C7sus4, Fsus4, F, Gm7, Bb, Dm11, and a few more. 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? The Hardest Part guitar melody tab.