This guide explains how to handle webhooks effectively in your Upstash Workflow applications. We’ll walk through:
  • setting up webhook endpoints
  • verifying webhook requests
  • and processing webhook events

GitHub Repository

You can find the project source code on GitHub.

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Overview

Webhooks allow external services to notify your application when events occur. For example, you can use webhooks to receive notifications when a new order is placed in your e-commerce store, a new user signs up, or a new message is sent in your chat application. Upstash Workflow provides a simple way to receive these events and trigger workflows based on the incoming data autonomously.

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Setting Up Webhook Endpoints

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Basic Setup

To create a webhook endpoint, use the serve function from @upstash/workflow: 
import { serve } from "@upstash/workflow/nextjs";

export const { POST } = serve(
  async (context) => {
    // Your webhook handling logic here
  },
  {
    initialPayloadParser: (payload) => {
      return payload;
    },
  }
);

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Request Validation

Always validate incoming webhook requests to ensure they’re legitimate. This way, no one other than the original webhook source can trigger your workflow. Here’s an example using Clerk webhooks with Svix: 
export const { POST } = serve<string>(async (context) => {
	const payloadString = context.requestPayload;
	const headerPayload = context.headers;

    let event: WebhookEvent;
    try {
    	event = await validateRequest(payloadString, headerPayload);
    } catch {
    	return
    }

    // Next steps based on the event

})

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Handling Webhook events

Use the context.run method to process webhook events in discrete, trackable steps: 
export const { POST } = serve(async (context) => {
  // ... Parse and validate the incoming request

  const user = await context.run<false | UserPayload>(
    "handle-webhook-event",
    async () => {
      if (event.type === "user.created") {
        const { id: clerkUserId, email_addresses, first_name } = event.data;
        const primaryEmail = email_addresses.find(
          (email) => (email.id = event.data.primary_email_address_id)
        );

        if (!primaryEmail) {
          return false;
        }

        return {
          event: event.type,
          userId: clerkUserId,
          email: primaryEmail.email_address,
          firstName: first_name,
        } as UserPayload;
      }
      return false;
    }
  );
});
After validating the webhook and extracting the initial user data, you’ll often need to perform additional operations like creating customer records, sending welcome emails etc. 
export const { POST } = serve(async (context) => {
  // ... Previous validation and user data extraction

  if (!user) {
    return;
  }

  const customer = await context.run("create-stripe-customer", async () => {
    return await stripe.customers.create({
      email: user.email,
      name: `${user.firstName} ${user.lastName}`,
      metadata: {
        userId: user.userId,
      },
    });
  });

  /// ... Additional steps
});
You’re now ready to perform any operation in the following steps.