I strongly disagree, you can work in Barcelona without knowing Catalan if you don't have a public facing job, like most tech-related duties are.
Spanish and Catalan are both official languages in Catalonia and everyone there understands and is able to speak Spanish (even more so than Catalan, given the amount of immigrants in Barcelona).
I'm from Spain and have lived in Barcelona without speaking Catalan at all, so don't spread misinformation.