Workflows, Workers - Workflows is now Generally Available

Workflows is now Generally Available (or "GA"): in short, it's ready for production workloads. Alongside marking Workflows as GA, we've introduced a number of changes during the beta period, including: A new waitForEvent API that allows a Workflow to wait for an event to occur before continuing execution. Increased concurrency: you can run up to 4,500 Workflow instances concurrently — and this will continue to grow. Improved observability, including new CPU time metrics that allow you to better understand which Workflow instances are consuming the most resources and/or contributing to your bill. Support for vitest for testing Workflows locally and in CI/CD pipelines. Workflows also supports the new increased CPU limits that apply to Workers, allowing you to run more CPU-intensive tasks (up to 5 minutes of CPU time per instance), not including the time spent waiting on network calls, AI models, or other I/O bound tasks. Human-in-the-loop The new step.waitForEvent API allows a Workflow instance to wait on events and data, enabling human-in-the-the-loop interactions, such as approving or rejecting a request, directly handling webhooks from other systems, or pushing event data to a Workflow while it's running. Because Workflows are just code, you can conditionally execute code based on the result of a waitForEvent call, and/or call waitForEvent multiple times in a single Workflow based on what the Workflow needs. For example, if you wanted to implement a human-in-the-loop approval process, you could use waitForEvent to wait for a user to approve or reject a request, and then conditionally execute code based on the result. JavaScript import { WorkflowEntrypoint , WorkflowStep , WorkflowEvent , } from "cloudflare:workers" ; export class MyWorkflow extends WorkflowEntrypoint { async run ( event , step ) { // Other steps in your Workflow let stripeEvent = await step . waitForEvent ( "receive invoice paid webhook from Stripe" , { type : "stripe-webhook" , timeout : "1 hour" }, ) ; // Rest of your Workflow } } TypeScript import { WorkflowEntrypoint , WorkflowStep , WorkflowEvent } from "cloudflare:workers" ; export class MyWorkflow extends WorkflowEntrypoint < Env , Params > { async run ( event : WorkflowEvent < Params >, step : WorkflowStep ) { // Other steps in your Workflow let stripeEvent = await step . waitForEvent < IncomingStripeWebhook > ( "receive invoice paid webhook from Stripe" , { type : "stripe-webhook" , timeout : "1 hour" } ) // Rest of your Workflow } } You can then send a Workflow an event from an external service via HTTP or from within a Worker using the Workers API for Workflows: JavaScript export default { async fetch ( req , env ) { const instanceId = new URL ( req . url ) . searchParams . get ( "instanceId" ) ; const webhookPayload = await req . json () ; let instance = await env . MY_WORKFLOW . get ( instanceId ) ; // Send our event, with `type` matching the event type defined in // our step.waitForEvent call await instance . sendEvent ( { type : "stripe-webhook" , payload : webhookPayload , } ) ; return Response . json ( { status : await instance . status () , } ) ; }, }; TypeScript export default { async fetch ( req : Request , env : Env ) { const instanceId = new URL ( req . url ) . searchParams . get ( "instanceId" ) const webhookPayload = await req . json < Payload > () let instance = await env . MY_WORKFLOW . get ( instanceId ) ; // Send our event, with `type` matching the event type defined in // our step.waitForEvent call await instance . sendEvent ( { type : "stripe-webhook" , payload : webhookPayload } ) return Response . json ( { status : await instance . status () , } ) ; }, }; Read the GA announcement blog to learn more about what landed as part of the Workflows GA.