Pinia
Pinia started as an experiment to redesign what a Store for Vue could look like with the Composition API around November 2019. Since then, the initial principles are still the same, but Pinia works for both Vue 2 and Vue 3 and doesn't require you to use the composition API. The API is the same for both except for installation and SSR, and these docs are targeted to Vue 3 with notes about Vue 2 whenever necessary so it can be read by Vue 2 and Vue 3 users!