HSTU¶
Hierarchical Sequential Transduction Units. Sequence architecture Shopify uses at the company scale to model buyer and merchant trajectories over time — not per-session but per-lifetime. Enables counterfactual rollouts from an intervention node (e.g. "at this point, we offered a discount — what changes downstream?").
Parakhin mentions it briefly in the context of simgym and modeling the merchant-as-entity; he'd referenced it at NeurIPS. The wiki flags this page as confidence: low because the details came from a single mention and the architecture's public literature isn't audited here.