Shawn Mendes got his first guitar at the age of 14, a major-label record deal at 15 and his first No. 1 album — last year’s “Handwritten” — at 16, thanks largely to the democratizing power of the internet. But since taking off on Vine, the looping micro-video app, with his #6secondcover versions of others’ pop hits, this Canadian singer has done something more impressive: He’s stuck around with songs of his own.
Unlike “Handwritten,” Mr. Mendes’s “Illuminate,” which he called a mix between Ed Sheeran and the John Mayer album “Continuum,” credits him as a songwriter on every track. Though many artists bristle at direct musical comparisons, Mr. Mendes is exceedingly open about his influences; his entire sonic development is documented in online videos, after all. (Mr. Sheeran and Mr. Mayer also serve as his big-brother figures in the industry, Mr. Mendes said.)