Introduction

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What are webhooks?

Postack uses webhooks to instantly notify you about events around SMS messages. We send these events as JSON payload to your registered HTTPS endpoint using a POST request. You can use these webhooks for various tasks such as:

• Respond to customer messages.
• Handle errors like undelivered messages.
• Produce data reports and perform analytics.

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Steps to receive webhooks

You can start receiving webhook events using the following steps:

• Create a local endpoint to receive events.
• Register your local endpoint with Postack.
• Send a test event to your endpoint.
• Deploy your endpoint to production.
• Register your production endpoint with Postack.

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1. Create a local endpoint to receive events

In your application, create a POST endpoint to receive events.

// pages/api/webhooks.ts
import { Webhook } from "svix";
import { buffer } from "micro";
import { NextApiRequest, NextApiResponse } from "next";

export const config = {
    api: {
        bodyParser: false,
    },
};

export default async function handler(req: NextApiRequest, res: NextApiResponse) {
    const payload = (await buffer(req)).toString();
    const headers = req.headers;

    const wh = new Webhook(process.env.POSTACK_WEBHOOK_SECRET);
    try {
        const msg = wh.verify(payload, headers);
    } catch (err) {
        res.status(400).json({});
    }

    // Do something with the message...
    res.json({});
}

You must return a 2xx (status code 200-299) response to let Postack know that you have successfully processed the webhook. Otherwise, Postack will try sending it again.

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2. Register your local endpoint with Postack

You can register your publicly accessible HTTPs endpoint on the Postack dashboard.

Once you have registered your endpoint, get the POSTACK_WEBHOOK_SECRET from the registered endpoint’s details page.

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3. Send a test event to your endpoint

You can either send an outbound test SMS to a known number or send an inbound SMS to your Postack number. Your endpoint should receive a webhook event within a second.

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4. Deploy your endpoint to production

Once you have tested your endpoint locally, you can deploy it to production.

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5. Register your production endpoint with Postack

Register your production endpoint on the Postack dashboard. You can either edit the existing endpoint which you just registered above or register a new one. Please make sure to rotate the POSTACK_WEBHOOK_SECRET before using it in production.