Workflow SDK vs trigger.dev

trigger.dev is an open-source, TypeScript-first durable task platform. Instead of replaying code, it snapshots the whole process with Checkpoint/Restore in Userspace (CRIU) at each wait point and restores it later. This design drives most of the differences with the Workflow SDK.

At a glance

What the limits mean in practice: trigger.dev caps task payloads at 3 MB and outputs at 10 MB (large model contexts and transcripts need external storage), and the 14-day maximum run time means human-in-the-loop flows that wait longer than two weeks can't complete in one run. The Vercel World limits are 50 MB payloads, 2 GB of state per run, and no run-duration cap.

The core difference: checkpoint/restore vs. replay

trigger.dev freezes the entire operating system process with CRIU when a task hits a wait point, then restores it later, so there's no replay and no determinism rule: you can call Date.now() or Math.random() anywhere, and prior steps don't re-execute. The cost is an execution model that requires CRIU-capable infrastructure (which makes self-hosting heavier than a plain container) and runs on trigger.dev's runtime as a separate deploy target.

The Workflow SDK reconstructs state by replaying the workflow function against its event log. That requires the workflow body to be deterministic (side effects go in "use step" functions), but it runs inside your existing app and deployment with no special host requirements, and the World abstraction lets you swap the storage/queue/stream layers.

Notably, both pin runs to a version so deploys never corrupt in-flight work: trigger.dev via atomic version-locking, the Workflow SDK via immutable-deployment pinning.

AI agents

trigger.dev offers AI SDK tool wrapping, a native useChat transport over its Realtime layer, resumable streaming, and durable multi-turn Sessions. The Workflow SDK offers WorkflowAgent directly inside the AI SDK plus native resumable streaming. Both support human-in-the-loop workflows (trigger.dev's wait.forToken and the Workflow SDK's hooks). Key differences are language support (trigger.dev is TypeScript-only; the Workflow SDK adds Python) and whether the agent runs in your app or on a dedicated platform.

Migrating from trigger.dev

The task() factory collapses into a plain function, and because the workflow body is replayed, move side effects into steps:

export async function processOrder(orderId: string) {
  'use workflow';
  const order = await loadOrder(orderId);
  return { orderId: order.id, status: 'completed' };
}

async function loadOrder(orderId: string) {
  'use step';
  const res = await fetch(`https://example.com/api/orders/${orderId}`);
  return res.json() as Promise<{ id: string }>;
}

npx skills add https://github.com/vercel/workflow --skill migrating-to-workflow-sdk

trigger.dev features without a direct Workflow SDK equivalent

Each row is a trigger.dev capability the Workflow SDK does not replicate one-to-one, paired with how to cover it on the Workflow SDK side:

Compiled from public documentation. Verify current trigger.dev limits and pricing against trigger.dev/docs. Not based on head-to-head benchmarks.