By the work of Donovan and Wemyss, the functor of noncommutative deformations of a flopping irreducible rational curve C in a threefold X is representable by an algebra called the contraction algebra. This talk is based on a joint work in progress with Joseph Karmazyn and Michael Wemyss, where we construct a DG-algebra from the data of periodic projective resolution of the simple module on the contraction algebra, and prove that it reconstructs the A∞-algebra ExtX*(OC(-1), OC(-1)). We also discuss relations of this DG-algebra with Booth's derived contraction algebra, and the Donovan-Wemyss conjecture.