Stately | Pinia-style state for Svelte 5

Familiar store ergonomics

Use `defineStore()` with option stores or setup stores while keeping direct mutation and Pinia-like helper names.

SSR-safe by default

Create request-scoped managers and provide them through Svelte context instead of leaking singleton state on the server.

Advanced flows stay opt-in

Add persistence, history, time travel, multi-tab sync, and async request control only where a store needs them.

Explicit workflow state

Model state machines with `createFsmPlugin()` when your store has real states, real transitions, and no patience for boolean soup.

Guardrails for live data

Add validation, selective subscriptions, action hooks, and cancellation-aware async orchestration without rewriting your store model.

Developer tooling included

Use the inspector drawer, Vite integration, and typed helper exports to understand what your stores are doing while they are doing it.

What you get

Stately is a Svelte 5 state library for teams who want a small, composed core runtime with explicit plugin-based features. It is designed for package consumers who want predictable store behavior in both SPA and SSR flows, with enough structure to model real app workflows — without ceremony where none is warranted, and with full ceremony where it genuinely is.

The documentation is organized so you can move from learning the API to applying it in real apps:

The guide explains the recommended patterns.

The reference breaks the public API into focused topics.

The examples page shows persistence, history, sync, async orchestration, and store composition in practice.

Feature map

Stately includes:

option stores and setup stores through defineStore()

request-scoped managers for SSR-safe SvelteKit usage

persistence with storage adapters, migrations, TTL expiry, and optional compression

history and time travel with batch recording

finite state machines with send(), matches(), and can()

multi-tab sync with transport abstractions and deterministic conflict handling

async loading, cancellation, and concurrency policies

validation that can reject and roll back invalid patches

developer tooling such as the inspector drawer and Vite plugin

Start here

Read the guide for installation, store definitions, SSR patterns, plugins, and release workflows.

Jump to Define stores if you want the fastest route to your first useful store.

Read Plugins when you need persistence, history, FSMs, sync, validation, async orchestration, or the inspector.

Use SSR and SvelteKit and SvelteKit data loading if the app renders on the server.

Jump to the API reference for the exported runtime surface.

Browse the packaged examples under src/lib/examples/ and the examples page for consumer-facing patterns that match the public API.

StatelyPinia-inspired state for Svelte 5 and SvelteKit