Introduction

kit is a small set of TypeScript packages that handle the boring problems every side project hits in the first week: state that needs to survive a refresh, HTTP calls that need to be cancellable and retryable, structured logs you can ship somewhere, and config you can validate at boot.

It’s deliberately scoped. Not a framework. Not a state-management opinion. Not a data-fetching mega-library. Four packages, each independently installable, each under a few KB, no peer-dependency soup.

What’s in the box

store-kit

A Zustand factory with the conventions you’d reach for anyway: persistence, versioned migrations, devtools, and a reset() that clears storage too. Same Zustand API otherwise — anything you know about Zustand still applies.

fetch-kit

A typed fetch wrapper plus three React hooks. Retries with backoff, timeouts via AbortController, an error class hierarchy you can instanceof, response caching, in-flight request dedupe, a GraphQL helper, optional schema validation, request/response interceptors. The React layer is a separate subpath — non-React consumers don’t pay for it.

log-kit

A structured logger with pluggable transports (console, HTTP, file, Datadog), composed however you want. Six levels, child loggers, performance markers, and per-transport failure isolation so a flaky shipping endpoint can’t take your app down.

config-kit

Loads config from env vars, dotenv files, static objects, or remote sources, then validates with whatever schema library you already use (Zod, Valibot, anything with a parse interface). Source ordering, override semantics, and a single typed config object at the end.

What it isn’t

• Not a TanStack Query replacement. fetch-kit has a simple response cache and in-flight dedupe, but it doesn’t do normalized caching, optimistic updates with rollback, or background refetching. If you need those, pair it with TanStack Query — or don’t, most apps don’t need it.
• Not a Redux. store-kit doesn’t try to be the one true source of state. Use as many stores as you want.
• Not a winston / pino replacement on the server. log-kit is small enough to use everywhere; if you need Node-specific transports beyond what’s bundled, write a custom transport (it’s an interface).
• Not a router, form library, or component framework. Compose with whatever you’re already using.

When to use it

Reach for kit when you’re starting a side project and want the boring parts already done. Skip it if your app needs sophisticated server-state caching, optimistic updates with rollback, or normalized state — those problems need bigger tools.