Abstract The forthcoming Euclid survey will be able to map the large scale structure with unprecedented precision, with the aim of tightly constraining the standard cosmological model and its most common extensions. The great sensitivity of Euclid can however also be exploited to test our most fundamental assumptions at the basis of the cosmological investigation. In this work we present two recent results of the Euclid Consortium, where forecast Euclid products are used alongside data from other surveys to constrain violation of the distance duality relation and time evolution in the fine-structure constant. We show how Euclid will significantly contribute in constraining these effects, both connected with the presence of new physics beyond the standard cosmological model.