Webhooks vs APIs: What's the Difference?

One of the most common questions developers ask when building integrations is whether to use webhooks or APIs. The short answer: you will probably use both. But understanding the differences, strengths, and ideal use cases for each approach is essential for building efficient, reliable systems. This guide breaks down the webhook vs API comparison so you can make the right architectural decision for every integration.

Understanding the Fundamentals

Before comparing webhooks and APIs, let us establish what each one actually is.

What Is an API?

An API (Application Programming Interface) is a set of endpoints that allow one application to request data or perform actions on another application. When you call an API, you send an HTTP request (GET, POST, PUT, DELETE) to a specific URL and receive a response containing the requested data or a confirmation of the action.

# API Request: You ask for data
GET https://api.example.com/orders/12345
Authorization: Bearer your-api-key

# API Response: The server sends back what you asked for
{
  "id": "12345",
  "status": "completed",
  "total": 99.99,
  "customer": "jane@example.com"
}

The key characteristic: you initiate the request. You decide when to ask, what to ask for, and how often to check.

What Is a Webhook?

A webhook is an HTTP POST request sent automatically from one system to another when an event occurs. You register a URL with the source system, and it sends data to that URL whenever something happens.

# Webhook: The source system tells you something happened
POST https://webhookify.app/wh/your-endpoint
Content-Type: application/json
X-Webhook-Signature: sha256=abc123...

{
  "event": "order.completed",
  "data": {
    "id": "12345",
    "status": "completed",
    "total": 99.99,
    "customer": "jane@example.com"
  }
}

The key characteristic: the source system initiates the request. You do not need to ask — the data comes to you.

Push vs Pull: The Core Difference

The fundamental distinction between webhooks and APIs is the direction of communication:

The Pull Model (APIs)

With the API pull model, your application is the client. You send requests to the server when you need information. This is like going to the mailbox to check for letters — you have to physically walk there and look.

Your App  ──── GET /orders ────>  Server
Your App  <─── Response ────────  Server
           (repeat every N seconds)

If you need real-time awareness of changes, you must poll — sending repeated requests at intervals to check for updates. Most of those requests return the same data or empty results, wasting bandwidth and server resources.

The Push Model (Webhooks)

With the webhook push model, the source system is the client. It sends requests to your endpoint when events occur. This is like having mail delivered to your door — it arrives when there is something new, and you do not waste time checking an empty mailbox.

Source System  ──── POST /webhook ────>  Your App
Source System  <─── 200 OK ────────────  Your App
               (only when events occur)

No wasted requests. No empty responses. Data arrives exactly when it is available.

Detailed Comparison

Let us compare webhooks and APIs across every dimension that matters for production systems:

Latency and Timeliness

APIs (Polling): Latency equals your polling interval. If you poll every 30 seconds, you might learn about an event up to 30 seconds after it happened. Polling every second reduces latency but dramatically increases server load.

Webhooks: Near real-time. Events are typically delivered within milliseconds to a few seconds of occurring. For time-sensitive operations like payment processing or security alerts, this difference is critical.

Winner: Webhooks for event notifications.

Resource Efficiency

APIs (Polling): Every poll request consumes bandwidth, server CPU, and database queries — even when nothing has changed. If you poll an endpoint every 10 seconds and events happen once per hour, that is 359 wasted requests for every useful one.

Webhooks: Resources are consumed only when events actually occur. A webhook endpoint that receives 100 events per day uses a tiny fraction of the resources that polling would consume.

Winner: Webhooks for event-driven data.

// Polling approach: wasteful
setInterval(async () => {
  const response = await fetch('https://api.example.com/orders?since=last_check');
  const orders = await response.json();
  if (orders.length > 0) {
    // Process new orders — but most checks return empty
    processOrders(orders);
  }
}, 10000); // Every 10 seconds, whether or not anything changed

// Webhook approach: efficient
app.post('/webhook/orders', (req, res) => {
  res.status(200).json({ received: true });
  // Only runs when there IS a new order
  processOrder(req.body);
});

Reliability and Control

APIs: You control the timing, frequency, and error handling of every request. If a request fails, you can retry immediately. You can implement circuit breakers, fallbacks, and timeout handling on your side.

Webhooks: The source system controls delivery. If your endpoint is down, you depend on the provider's retry logic. Different providers have different retry policies, and some may drop events after a certain number of failures.

Winner: APIs for guaranteed data retrieval.

Complexity

APIs (Polling): Simpler to implement initially. You write a function that makes HTTP requests on a schedule. No public endpoint required, no signature verification needed, no retry handling on the receiving side.

Webhooks: Requires a publicly accessible endpoint, signature verification, idempotency handling, and proper error handling. More setup upfront, but more efficient long-term.

Winner: APIs for simplicity; Webhooks for long-term efficiency.

Scalability

APIs (Polling): Scales poorly. More resources to monitor means more polling requests. Monitoring 1,000 resources at 10-second intervals means 100 requests per second — constantly.

Webhooks: Scales with event volume, not with the number of resources you are watching. You can monitor a million resources and only process events when they actually change.

Winner: Webhooks at scale.

When to Use APIs

APIs are the right choice when:

• You need data on demand. User clicks a button, your app fetches their order history. This is a classic API use case.
• You need to perform actions. Creating a customer, updating an order, deleting a resource — these are API operations, not webhook use cases.
• You need to query or search. Finding all orders above $100 from the last week requires an API with query parameters. Webhooks cannot provide this.
• The source does not support webhooks. Some systems only offer APIs. Polling is your only option.
• You need guaranteed data consistency. When reconciling data between systems, an API lets you fetch the complete current state.

// Good API use cases
const customer = await api.getCustomer(customerId);
const searchResults = await api.searchOrders({ minAmount: 100, since: '2026-01-01' });
const newOrder = await api.createOrder({ items, customer, shipping });

When to Use Webhooks

Webhooks are the right choice when:

• You need real-time notifications. Payment received, order placed, user signed up — events that should trigger immediate action.
• You need to react to changes. Status updates, inventory changes, price modifications — anything where you need to know as soon as it happens.
• You are building event-driven architectures. Microservices that react to events from other services communicate naturally through webhooks.
• Efficiency matters. When events are infrequent relative to how often you would need to poll, webhooks save enormous resources.
• You are integrating with third-party platforms. Stripe, GitHub, Shopify, and most SaaS platforms push data through webhooks.

// Good webhook use cases
app.post('/webhooks/stripe', (req, res) => {
  res.status(200).send();
  switch (req.body.type) {
    case 'payment_intent.succeeded':
      fulfillOrder(req.body.data);
      break;
    case 'customer.subscription.deleted':
      handleChurn(req.body.data);
      break;
  }
});

The Hybrid Approach: Best of Both Worlds

In practice, most production integrations use both webhooks and APIs together. This hybrid approach gives you real-time responsiveness with guaranteed data consistency.

Pattern 1: Webhook Notification + API Fetch

The webhook tells you something happened; the API gives you the full details:

app.post('/webhooks/orders', async (req, res) => {
  res.status(200).send();

  const { order_id } = req.body.data;

  // Webhook tells us a new order exists
  // API gives us the complete order details
  const fullOrder = await api.getOrder(order_id);
  await processOrder(fullOrder);
});

This pattern is useful when webhook payloads are small or when you need the most up-to-date data (the order might have changed between the event firing and your processing).

Pattern 2: Webhook Primary + Polling Fallback

Webhooks handle real-time delivery; a scheduled job catches anything that was missed:

// Primary: webhook handler processes events in real-time
app.post('/webhooks/payments', handlePaymentWebhook);

// Fallback: hourly reconciliation catches missed webhooks
cron.schedule('0 * * * *', async () => {
  const recentPayments = await api.getPayments({ since: oneHourAgo() });
  for (const payment of recentPayments) {
    await reconcilePayment(payment); // Idempotent — safe to process twice
  }
});

Pattern 3: Webhook for Events + API for State

Webhooks notify you about changes; APIs provide the current state of the world:

// Webhooks keep your local cache updated
app.post('/webhooks/inventory', async (req, res) => {
  res.status(200).send();
  await updateLocalInventory(req.body.data);
});

// API provides full inventory for initial sync or reconciliation
async function fullInventorySync() {
  const inventory = await api.getAllInventory();
  await replaceLocalInventory(inventory);
}

Performance Comparison: Real Numbers

Let us quantify the difference with a realistic scenario. Imagine you need to monitor an e-commerce platform for new orders. The platform receives an average of 50 orders per hour.

Polling Approach

• Polling interval: 10 seconds
• Requests per hour: 360
• Useful requests (containing new data): ~50
• Wasted requests: ~310 (86% waste)
• Average latency: 5 seconds (half the polling interval)
• Monthly API calls: 259,200

Webhook Approach

• Requests per hour: ~50 (only when orders arrive)
• Wasted requests: 0
• Average latency: < 1 second
• Monthly webhook deliveries: ~36,000

The webhook approach uses 86% fewer requests and delivers data 5x faster. At scale, these savings are enormous — fewer servers, lower bandwidth costs, and happier API rate limits.

Common Misconceptions

"Webhooks are just reverse APIs." Not exactly. While webhooks use HTTP (like APIs), they serve a fundamentally different purpose. APIs are request-response interfaces for data access and manipulation. Webhooks are event notification mechanisms. They complement each other rather than being mirrors.

"Webhooks are unreliable." Webhook delivery mechanisms have matured significantly. Most providers implement robust retry logic with exponential backoff. The real reliability challenge is on the receiving side — ensuring your endpoint stays up and processes events correctly. Tools like Webhookify help you monitor delivery health and catch failures.

"Polling is simpler, so it is better." Polling is simpler to set up initially, but its operational complexity grows with scale. Managing rate limits, handling empty responses, tuning polling intervals, and dealing with the inherent latency creates ongoing maintenance burden. Webhooks have higher setup cost but lower operational overhead.

"I need to choose one or the other." You don't. The hybrid approach is the industry standard for production systems. Use webhooks for real-time event handling and APIs for data retrieval, actions, and reconciliation.

Making the Decision

Here is a simple decision framework:

Use webhooks when:

• Events are infrequent relative to how often you would poll
• Real-time notification matters
• You want to minimize API usage and bandwidth
• The source platform supports webhooks

Use APIs when:

• You need data on demand
• You need to perform write operations
• You need to query or search data
• The source does not support webhooks

Use both when:

• You need real-time updates AND on-demand data access
• Reliability is critical (webhooks for speed, polling for safety)
• You are building a production integration that needs to be bulletproof

Further Reading

• The Complete Guide to Webhooks — master webhook fundamentals
• How Webhooks Work: A Technical Deep Dive — understand the internals
• Webhook Security Best Practices — protect your endpoints
• Webhook Error Handling Best Practices — build resilient webhook consumers

Related Articles

• The Complete Guide to Webhooks
• How Webhooks Work: A Technical Deep Dive
• How to Set Up Stripe Webhook Notifications
• How to Set Up Shopify Webhook Notifications
• Building Real-Time Analytics with Webhooks