Vercel

The Vercel World is a fully-managed workflow backend for applications deployed on Vercel. It provides scalable storage, distributed queuing, and automatic authentication with zero configuration.

When you deploy to Vercel, workflows automatically use the Vercel World - no setup required.

Usage

Deploy your application to Vercel:

vercel deploy

That's it. Vercel automatically:

• Selects the Vercel World backend
• Configures authentication using OIDC tokens
• Provisions storage and queuing infrastructure
• Isolates data per environment (production, preview, development)

Vercel platform documentation

For complete details on pricing, usage limits, and included allotments on Vercel, see the official Vercel documentation:

• Vercel Workflow — Pricing details, concepts, and observability for Workflow on Vercel
• Vercel limits — Platform-wide limits including Workflow-specific constraints
• Vercel Hobby plan — Free tier included usage for Workflow and other resources

For self-hosted deployments, use the Postgres World. For local development, use the Local World.

Limitations

• Single-region deployment - On the 4.x release line, the backend infrastructure is used only in iad1. Applications in other regions will route workflow requests to iad1, which may result in higher latency. For best performance, deploy your Vercel apps using Workflow to iad1 — or upgrade to workflow 5.0.0-beta.33+ for multi-region support.

• Data residency - On the 4.x release line, independently of the deployment location of your application, the data for your workflows will be stored in the iad1 region.

Observability

Workflow observability is built into the Vercel dashboard on your project page. It respects your existing authentication and project permission settings.

The workflow CLI commands open a browser window deeplinked to the Vercel dashboard:

# List workflow runs (opens Vercel dashboard)
npx workflow inspect runs --backend vercel

# Launch the web UI (opens Vercel dashboard)
npx workflow web --backend vercel

The CLI automatically retrieves authentication from the Vercel CLI (vercel login) and infers project/team IDs from your local Vercel project linking.

To use the local observability UI instead of the Vercel dashboard:

npx workflow web --backend vercel --localUi

To override the automatic configuration:

npx workflow inspect runs \
  --backend vercel \
  --env production \
  --project my-project \
  --team my-team \
  --authToken <your-token>

Learn more in the Observability documentation.

Testing & Compatibility

Configuration

The Vercel World requires no configuration when deployed to Vercel. For advanced use cases, you can override settings programmatically via createVercelWorld().

WORKFLOW_VERCEL_ENV

The Vercel environment to use. Options: production, preview, development. Automatically detected.

WORKFLOW_VERCEL_AUTH_TOKEN

Authentication token for API requests. Automatically detected.

WORKFLOW_VERCEL_PROJECT

Vercel project ID for API requests. Automatically detected.

WORKFLOW_VERCEL_TEAM

Vercel team ID for API requests. Automatically detected.

WORKFLOW_VERCEL_BACKEND_URL

Custom base URL for the Vercel workflow API. Automatically detected.

WORKFLOW_SEQUENTIAL_REPLAYS

Set WORKFLOW_SEQUENTIAL_REPLAYS=1 to guarantee that at most one orchestrator (flow) invocation runs at a time per workflow run. This behavior is off by default; without it, the runtime relies on idempotency and the event log to tolerate concurrent flow invocations of the same run.

When enabled, each run is given its own queue topic and the flow route is configured with maxConcurrency: 1, so Vercel Queues processes flow messages for a given run strictly one at a time. Step routes are unaffected and continue to run with full concurrency.

Because it routes each run's flow invocations through a dedicated maxConcurrency: 1 queue topic, enabling this might lead to higher queue performance overhead.

Programmatic configuration

import { createVercelWorld } from "@workflow/world-vercel";

const world = createVercelWorld({
  token: process.env.WORKFLOW_VERCEL_AUTH_TOKEN,
  baseUrl: "https://api.vercel.com/v1/workflow",
  projectConfig: {
    projectId: "my-project",
    teamId: "my-team",
    environment: "production",
  },
});

Versioning

On Vercel, workflow runs are pegged to the deployment that started them. This means:

• Existing workflow runs continue executing on their original deployment, even as new code is deployed
• New workflow runs start on the latest deployment
• Code changes won't break in-flight workflows

This ensures long-running workflows complete reliably without being affected by subsequent deployments.

For the full model, including rerunning on latest and explicit upgrade boundaries, see Versioning.

Security

Consumer function security

Workflow handler functions on Vercel are not accessible through public endpoints. During the build step, the Workflow SDK registers each handler as only reachable by Vercel Queue, by using the experimentalTriggers configuration in .vc-config.json:

{
  "experimentalTriggers": [
    {
      "type": "queue/v2beta",
      "topic": "__wkf_step_*",
      "consumer": "default",
    }
  ]
}

Practically, this means:

• You don't need to add authentication or authorization logic to workflow handlers
• Unauthorized requests can never reach the step or workflow functions
• Only messages delivered through Vercel Queues can trigger execution
• Handlers receive only a message ID that must be retrieved from Vercel's backend, making it impossible to craft custom payloads

How It Works

The Vercel World uses Vercel's infrastructure for workflow execution:

• Storage - Workflow data is stored in Vercel's cloud with automatic replication and end-to-end encryption
• Queuing - Steps are distributed across serverless functions via Vercel Queues with automatic retries and consumer function security
• Authentication - OIDC tokens provide secure, automatic authentication

For more details, see the Vercel Workflow documentation.