Summary: There are two identical twins who are amazing with music. They are part of a circus and when playing, odd things happen to their audience which starts attracting the wrong attention and they are then chased around by these things I think were called Executors because of their display of magical, musical powers!
Date Read: 2-3 years ago!
Date Published: Probably also 2-3 years ago!
Book Details: Probably around 400 pages; I think hardcover; cover may have been purple-ish...
Author: No idea...
The Trilogy of Two (2015) by Juman Malouf?
Identical twins Sonja and Charlotte are musical prodigies with extraordinary powers. Born on All-Hallows-Eve, the girls could play music before they could walk. They were found one night by Tatty, the Tattooed Lady of the circus, in a pail on her doorstep with only a note and a heart-shaped locket. They’ve been with Tatty ever since, roaming the Outskirts in the circus caravans, moving from place to place.
But lately, curious things have started to happen when they play their instruments. During one of their performances, the girls accidentally levitate their entire audience, drawing too much unwanted attention. Soon, ominous Enforcers come after them, and Charlotte and Sonja must embark on a perilous journey through enchanted lands in hopes of unlocking the secrets of their mysterious past.
Cover art is grey/green.
Found with the Google query
book "identical twins" music powers circus site:goodreads.com.