Principal ML Engineer

Harnham is seeking a Principal Machine Learning Engineer in Barcelona, offering a €135,000 base salary with a €15,000 bonus and an OTE of €150,000. The role supports fully remote or hybrid work (2 days in office). You will define technical direction for large-scale ML systems while remaining hands-on across the full model lifecycle. You will lead end-to-end ML initiatives in recommendation, targeting, bidding optimization, and lifecycle modelling, partnering with senior engineers and