Just infinite Coxeter groups are precisely the irreducible affine Coxeter groups. This result serves as a key tool to establish that irreducible affine Coxeter groups are profinitely rigid within the class of all Coxeter groups. Furthermore, this rigidity extends to all affine Coxeter groups. To achieve this generalization, we replace the just infinite condition with an analysis of the relationship between finite normal subgroups of Coxeter groups and those of their profinite completions, ultimately reducing the problem to affine Coxeter groups without finite normal subgroups. link: https://www.uni-muenster.de/AGKramer/index.php?name=TSWS24&menu=teesemi&lang=de