With the growth and overcrowding of the internet, the use of online social networks has been increasing. Currently, social networks are used by a wide variety of users-with different objectives and in different contexts of use-, so it is essential to design intuitive and easy to use social network applications that generate a positive user experience (UX). The heuristic evaluation is a well-known evaluation method that allows detecting usability problems; a group of experts evaluates a product and/or system using a set of heuristics as a guide. Although the heuristic evaluation is oriented to evaluate the usability, it can be useful to evaluate other aspects related to the UX. Due to the specific features of social networks, it is necessary to have a specific set of heuristics to evaluate them. Sets of specific heuristics for social networks have been proposed, but they focus on evaluating the only usability. This article presents a set of heuristics that attend not only usability issues, but other UX factors as well, social network user experience heuristics (SNUXH). The new set of heuristics was developed, validated, and refined in four iterations. The results obtained in the experimental validation indicate that the SNUXH set is useful and more effective than generic heuristics (Nielsen's heuristics) when evaluating social networks.