Alexandra Cahill of Billboard gave the song a positive review, writing, "vocalist Hayley Williams captures the tension and urgency between Edward and Bella with an impassioned, yet restrained performance". Cahill also stated, "expertly crafted follow-up Decode promises to stake a claim at modern rock and top 40 radio". Leah Greenblatt of Entertainment Weekly said that "Decode" took a step away from Paramore's "bouncier punk-pop sound for a more sprawling, Evanescence-like romanticism". Heather Phares of AllMusic complimented Williams's "crystalline vocals" on the track, but conceded that it failed to "match the best moments from the band's albums."
