Webhooks and Serverless for Fully Reactive Campaign Logic

Introduction: Reactivity Is the New Speed

Static campaigns waste money. If your ads do not reflect current inventory, pricing or demand, your budget burns while conversions fall. I solve this using a simple principle: when your business changes, your marketing should react immediately.

The way I do this is by connecting product events and user activity to ad and email automation using webhooks and serverless infrastructure. This lets me update campaigns across Google, Microsoft and Meta in real time, without human delay or bloated logic.

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1. When a Product Is Added → Auto Create Campaigns

Let’s say you add a new product to your ecommerce store. With a webhook sent from your platform (e.g. Shopify or a custom backend), I trigger an AWS Lambda function that creates:

• A new RSA (responsive search ad) on Google
• A new ad set in Meta Ads Manager
• A keyword group for Microsoft Ads

Shopify Webhook Setup (Node.js):

app.post('/webhook/products/create', async (req, res) => {
  const product = req.body;
  await fetch('https://your-lambda-endpoint.amazonaws.com/trigger', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ sku: product.sku, title: product.title, price: product.price })
  });
  res.status(200).send('Webhook received');
});

AWS Lambda Skeleton (Python):

def lambda_handler(event, context):
    product = event['body']
    create_google_rsa(product)
    create_meta_ad(product)
    create_bing_ad(product)
    return { 'statusCode': 200, 'body': 'Campaigns triggered' }

Each create_... function handles the platform-specific API logic. I modularise these to allow fast rollout.

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2. When Stock Dips or Sales Expire → Auto Pause or Update

Campaigns that keep running after the sale ends or the product goes out of stock erode trust and increase bounce.

I deploy Cloudflare Workers to listen to periodic stock snapshots and scheduled pricing changes. When:

• Inventory < threshold
• Sale flag ends

The worker calls:

• Google Ads API to pause the campaign
• Meta Marketing API to change ad text
• Microsoft Ads to lower bids

Example: Sale Expiry Handler (Cloudflare Worker in JavaScript)

async function handleSaleExpiry(req) {
  const { sku, saleActive } = await req.json();
  if (!saleActive) {
    await updateGoogleAdText(sku, 'Now ended');
    await pauseMetaAd(sku);
  }
  return new Response('Ad updated');
}

This keeps campaigns aligned with business truth, no more serving expired offers.

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3. When a Cart Is Abandoned → Margin Check → Trigger Logic

Instead of sending a generic discount email after cart abandonment, I fire a webhook to check margin and decide:

• High margin: trigger email with discount offer
• Low margin: skip email, trigger remarketing ad instead

This logic lives in a serverless backend that queries product cost from your pricing system.

Abandonment Logic (AWS Lambda in Python):

def lambda_handler(event, context):
    cart = event['cart']
    margin = get_margin(cart['product_id'])

    if margin > 0.4:
        trigger_discount_email(cart['user_id'])
    else:
        push_user_to_remarketing_audience(cart['user_id'])
    return { 'statusCode': 200 }

This avoids margin bleed while still recovering intent.

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Why Serverless? Flexibility and Speed

Traditional automation chains are slow. Serverless logic lets me:

• Deploy independent micro-automations
• Scale instantly
• Integrate with any event source

I often pair AWS Lambda for backend logic with Cloudflare Workers for fast edge response. This means whether it is stock change, user intent, or a new product drop, your marketing stack reacts live.

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Final Thought: If It Moves, React

Marketing campaigns should follow your product and buyer behaviour, not the other way around. By using webhooks and serverless infrastructure, I turn your backend events into live marketing decisions.

This is not just efficiency. It is control. You shape what happens when your customer or catalogue changes.

If you want to build a reactive stack where campaigns adapt without waiting, I can help architect it, from the webhook logic to platform execution and margin-aware rules.