Type-safe durable execution for TypeScript. Workflows are ordinary async functions that can pause, persist progress to an append-only log, and resume after approvals, webhooks, timers, or process restarts.
pnpm add @tanstack/workflow-coreInstall zod or another Standard Schema-compatible library if you want runtime validation for workflow inputs, outputs, state, or signal payloads.
import {
createWorkflow,
inMemoryRunStore,
runWorkflow,
} from '@tanstack/workflow-core'
import { z } from 'zod'
const checkout = createWorkflow({
id: 'checkout',
input: z.object({ userId: z.string(), amount: z.number() }),
output: z.object({ status: z.enum(['approved', 'rejected']) }),
}).handler(async (ctx) => {
const charge = await ctx.step('charge-card', (stepCtx) =>
stripe.charges.create(
{ customer: ctx.input.userId, amount: ctx.input.amount },
{ idempotencyKey: stepCtx.id },
),
)
if (ctx.input.amount > 10_000) {
const decision = await ctx.approve({ title: 'Approve large charge?' })
if (!decision.approved) return { status: 'rejected' as const }
}
await ctx.step('send-receipt', () => sendReceipt(charge.id))
return { status: 'approved' as const }
})
const store = inMemoryRunStore()
for await (const event of runWorkflow({
workflow: checkout,
input: { userId: 'cus_123', amount: 4200 },
runStore: store,
})) {
console.log(event.type, event)
}- Side effects live inside
ctx.step(id, fn), which records results and skips re-execution on replay. ctx.waitForEvent,ctx.approve,ctx.sleep, andctx.sleepUntilpause runs until the host delivers a matching signal or approval.ctx.now()andctx.uuid()record deterministic values for replay.- Middleware can extend
ctxwith typed dependencies such as users, database handles, or tracing. - Storage is pluggable through
RunStore; the package ships an in-memory store for local development and tests.
@tanstack/workflow-core: engine, workflow builder, middleware, event types, request parsing helpers, version routing, and in-memoryRunStore.
Storage adapters, framework bindings, and devtools are planned as follow-up packages.
pnpm install
pnpm --filter @tanstack/workflow-core test:lib
pnpm --filter @tanstack/workflow-core test:types
pnpm --filter @tanstack/workflow-core build
pnpm testMIT