Host adapters

Host adapters turn provider-native cron or scheduled function entrypoints into a bounded runtime.sweep() call.

They are intentionally thin. Workflow semantics live in the runtime and store. Documentation and adapter development should prioritize partner environments: Cloudflare, Railway, and Netlify. Vercel remains an important compatibility target, but examples should not make it the default host.

Common behavior

Current packaged host adapters:

call materializeWorkflowSchedules
call runtime.sweep
default includeEvents to false
return a compact JSON summary
optionally include the full sweep result for debugging

Cloudflare

Install:

pnpm add @tanstack/workflow-cloudflare

`createCloudflareWorkflowScheduledHandler`

import { createCloudflareWorkflowScheduledHandler } from '@tanstack/workflow-cloudflare'

export default {
  scheduled: createCloudflareWorkflowScheduledHandler({
    runtime: ({ env }) => createWorkflowRuntime(env),
    maxScheduledRuns: 25,
    maxTimers: 25,
    maxDurationMs: 25_000,
  }),
}

Options:

Option	Purpose
`runtime`	Required `WorkflowRuntimeDefinition`, or a function that creates one from `controller`, `env`, and `ctx`.
`now`	Optional timestamp provider. Defaults to `controller.scheduledTime`.
`leaseOwner`	String or function for worker identity.
`limit`	Shared fallback limit for schedules and timers.
`maxScheduledRuns`	Maximum schedule buckets to start.
`maxTimers`	Maximum timers to resume.
`maxDurationMs`	Sweep wall-clock budget.
`leaseMs`	Lease duration.
`includeEvents`	Whether retained run results include events. Defaults to false.
`maxEvents`	Maximum retained events per run result.
`includeSweepResult`	Include full sweep result in the returned object. Defaults to false.
`materializeSchedules`	Set false to skip schedule materialization.
`cronLookbackMs`	Lookback window for cron schedule materialization.

Configure Cloudflare Cron Triggers directly in wrangler.json or wrangler.toml. The adapter does not wrap that static platform config.

Railway

Install:

pnpm add @tanstack/workflow-railway

`createRailwayWorkflowCronCommand`

import { createRailwayWorkflowCronCommand } from '@tanstack/workflow-railway'

const sweep = createRailwayWorkflowCronCommand({
  runtime,
  maxScheduledRuns: 25,
  maxTimers: 25,
  maxDurationMs: 55_000,
  logSummary: true,
})

await sweep()

Options:

Option	Purpose
`runtime`	Required `WorkflowRuntimeDefinition`.
`now`	Optional timestamp provider.
`leaseOwner`	String or function for worker identity.
`limit`	Shared fallback limit for schedules and timers.
`maxScheduledRuns`	Maximum schedule buckets to start.
`maxTimers`	Maximum timers to resume.
`maxDurationMs`	Sweep wall-clock budget.
`leaseMs`	Lease duration.
`includeEvents`	Whether retained run results include events. Defaults to false.
`maxEvents`	Maximum retained events per run result.
`includeSweepResult`	Include full sweep result in the returned object. Defaults to false.
`materializeSchedules`	Set false to skip schedule materialization.
`cronLookbackMs`	Lookback window for cron schedule materialization.
`logSummary`	`true` to log JSON summary, or a function to receive the result.

Configure the Railway Cron Job directly in railway.toml or railway.json:

[deploy]
startCommand = "pnpm workflow:sweep"
cronSchedule = "*/5 * * * *"
restartPolicyType = "NEVER"

Netlify

Install:

pnpm add @tanstack/workflow-netlify

`createNetlifyWorkflowSweepHandler`

import { createNetlifyWorkflowSweepHandler } from '@tanstack/workflow-netlify'

export default createNetlifyWorkflowSweepHandler({
  runtime,
  maxScheduledRuns: 25,
  maxTimers: 25,
  maxDurationMs: 25_000,
})

Options:

Option	Purpose
`runtime`	Required `WorkflowRuntimeDefinition`.
`now`	Optional timestamp provider.
`leaseOwner`	String or function for worker identity.
`limit`	Shared fallback limit for schedules and timers.
`maxScheduledRuns`	Maximum schedule buckets to start.
`maxTimers`	Maximum timers to resume.
`maxDurationMs`	Sweep wall-clock budget.
`leaseMs`	Lease duration.
`includeEvents`	Whether retained run results include events. Defaults to false.
`maxEvents`	Maximum retained events per run result.
`includeSweepResult`	Include full sweep result in JSON response. Defaults to false.
`materializeSchedules`	Set false to skip schedule materialization.
`cronLookbackMs`	Lookback window for cron schedule materialization.

Export the Netlify Scheduled Function config object directly. Netlify needs that object to be statically visible:

export const config = {
  schedule: '*/5 * * * *',
}

The Netlify adapter only wakes the runtime. Apply the store adapter's package-owned migration during deploy/setup; do not define Workflow's workflow_* tables in application schema files unless you are intentionally building typed admin access.

Vercel

Install:

pnpm add @tanstack/workflow-vercel

`createVercelWorkflowSweepHandler`

import { createVercelWorkflowSweepHandler } from '@tanstack/workflow-vercel'

export const GET = createVercelWorkflowSweepHandler({
  runtime,
  cronSecret: process.env.CRON_SECRET,
  maxScheduledRuns: 25,
  maxTimers: 25,
  maxDurationMs: 55_000,
})

Options:

Option	Purpose
`runtime`	Required `WorkflowRuntimeDefinition`.
`now`	Optional timestamp provider.
`leaseOwner`	String or function for worker identity.
`limit`	Shared fallback limit for schedules and timers.
`maxScheduledRuns`	Maximum schedule buckets to start.
`maxTimers`	Maximum timers to resume.
`maxDurationMs`	Sweep wall-clock budget.
`leaseMs`	Lease duration.
`includeEvents`	Whether retained run results include events. Defaults to false.
`maxEvents`	Maximum retained events per run result.
`includeSweepResult`	Include full sweep result in JSON response. Defaults to false.
`materializeSchedules`	Set false to skip schedule materialization.
`cronLookbackMs`	Lookback window for cron schedule materialization.
`cronSecret`	Expected `Authorization: Bearer <secret>` value.

Configure Vercel Cron directly in vercel.json:

{
  "$schema": "https://openapi.vercel.sh/vercel.json",
  "crons": [{ "path": "/api/workflow/sweep", "schedule": "*/5 * * * *" }]
}

The Vercel adapter only wakes the runtime. Apply the store adapter's package-owned migration during deploy/setup; route code owns host config, while Workflow owns the runtime persistence schema.

Response shape

Successful adapters return:

interface SweepResponse {
  ok: true
  now: number
  leaseOwner: string
  materialized: ReadonlyArray<MaterializedWorkflowSchedule>
  summary: {
    materialized: number
    scheduled: Partial<Record<WorkflowRuntimeRunResultKind, number>>
    timers: Partial<Record<WorkflowRuntimeRunResultKind, number>>
    eventCount: number
    returnedEventCount: number
  }
  deadlineReached: boolean
  remainingMayExist: boolean
  sweep?: WorkflowRuntimeSweepResult
}

Use the summary for normal logs and monitoring. Include the full sweep only for debugging.

Re-exported schedule helpers

Both adapters re-export:

materializeWorkflowSchedules

and the related materialization types from @tanstack/workflow-runtime.

Host Adapters

Host adapters

Common behavior

Cloudflare

createCloudflareWorkflowScheduledHandler

Railway

createRailwayWorkflowCronCommand

Netlify

createNetlifyWorkflowSweepHandler

Vercel

createVercelWorkflowSweepHandler

Response shape

Re-exported schedule helpers

`createCloudflareWorkflowScheduledHandler`

`createRailwayWorkflowCronCommand`

`createNetlifyWorkflowSweepHandler`

`createVercelWorkflowSweepHandler`