LoRA (Low-Rank Adaptation)
A cheap fine-tuning method that trains a small add-on instead of updating the whole model.
LoRA freezes the base weights and learns a small number of extra parameters alongside them. The result is a lightweight adapter file — megabytes, not gigabytes — that can be swapped per task and trained on modest hardware. It is why fine-tuning stopped being the exclusive privilege of large labs.
In practice: One base model plus five LoRA adapters serving five brand voices.