Webhook vs API: The Differences Between APIs & Webhooks | SendGrid (2024)

Webhook vs API: What's the Difference Between Them?

Webhook vs API

Webhooks and APIs enable different software systems to interact and communicate with each other. However, they operate a bit differently.

• A webhook is a user-defined HTTP callback that's triggered automatically when something happens.
• An API uses a more direct and request-driven interaction where one applications makes a request to another to receive a response.

A webhook pushes data to other applications, while an API pulls data upon request.Below, we'll explore the difference between APIs and webhooks more.

What is an API?

API stands for Application Programming Interface. Rather than focusing on what it is, let's talk about what APIs enable. APIs can share data or functionality, acting as the connective tissue of the digital world. They're like the waiters of the internet—taking your order, relaying it to the kitchen, and bringing back exactly what you asked for.

APIs can share data or functionality, acting as the connective tissue of the digital world. They're like the waiters of the internet—taking your order, relaying it to the kitchen, and bringing back exactly what you asked for.

Here are some examples of what APIs can do:

• Data lookup: You might use a places API to find restaurants by location or name, retrieving various data points about each place. It's like having a super-powered Yellow Pages at your fingertips.
• Functionality integration: You could combine that restaurant data with a mapping API to display your results visually. Suddenly, you're not just reading about nearby pizza joints—you're seeing them plotted on a map.
• Payment processing: Many e-commerce sites use payment gateway APIs to securely handle transactions. It's the digital equivalent of a credit card machine, but way more sophisticated.
• Social media integration: Ever noticed those "Share on Twitter" buttons? That's an API in action, allowing websites to tap into social media functionality.

When programmers make a request to an API, they receive a response. It's like a digital conversation. For instance, using our Web API to send an email works like this:

• You pass the email contents with the request—think of it as handing a letter to a postal worker.
• If all goes well, you'll get a response confirming success—like getting a delivery confirmation.

What is a webhook?

Sometimes people call webhooks reverse APIs, but perhaps more accurately a webhook lets you skip a step. With most APIs there's a request followed by a response. No request is required for a webhook, it just sends the data when it's available.

While APIs wait for you to ask for information, webhooks can't wait to tell you what's happening. They skip the whole "ask and you shall receive" dance and jump straight to "hey, something cool just happened."

Here's how webhooks work:

• Automatic notifications: Instead of constantly checking for updates, webhooks notify you when something changes. It's like having a friend who texts you the moment your favorite band announces a new album.
• Real-time data delivery: Webhooks send data as soon as it's available. Imagine if your pizza delivery guy showed up at your door the instant your pizza came out of the oven—that's webhook speed.
• Efficiency: By eliminating the need for constant polling, webhooks save resources and reduce unnecessary traffic. It's the difference between repeatedly asking "Are we there yet?" on a road trip and having the GPS alert you when you've arrived.

To use a webhook, you follow these steps:

1. Register a URL: You provide a URL to the service provider. This URL is like your digital mailbox—it's where you'll receive all the updates.
2. Specify triggers: In some cases, you can tell the provider which situations should prompt data sending. It's like setting up custom notifications on your phone—you decide what's important enough to ping you about.
3. Receive data: Whenever there's new relevant information, the webhook sends it to your specified URL.

At SendGrid, we use webhooks to provide real-time data about the emails you send. Our Event Webhook, for instance, can tell you instantly when an email bounces or when a recipient clicks a link.

So, what's the difference between APIs and webhooks?

APIs are typically used for creating interfaces that other software can interact with on-demand, while Webhooks provide a way to automate interactions based on specific events. Let's take a closer look at the differences between APIs and webhooks to get a complete understanding:

"Call Me When He's Warmed Up"

As the game progresses, they often want to change pitchers. To do this requires the new pitcher to first warm up in the bullpen, which is usually over 300 feet from the team's dugout.

If you watch baseball on television, you'll often see the manager pick up a phone in the dugout. He's making a call to the bullpen to check on the new pitcher.

• "Is he warmed up yet?"
• "Not yet"

Then he hangs up the phone. In a few minutes, he'll have to call again. Programmers would call this polling and it's process-intensive for both sides. A webhook lets you say, "call me when he's warmed up."

Examples of Webhooks vs APIs

SendGrid has two distinct webhooks related to each direction that email flows:

1. Event Webhook provides data about the emails you send, such as bounces and when the recipient clicks a link.
2. Inbound Parse Webhook allows your application to receive email as soon as a message comes in.

Some non-SendGrid webhooks:

• Twilio's webhooks send text messages and voice calls to your application.
• DropBox just announced webhooks to provide real-time notifications about file changes in Dropbox.
• Metwit added webhooks to its weather API to provide notifications when specific types of weather occur in a particular location. It inspired my post on why every API needs webhooks.

Get started with webhooks

Now, you know all the differences between a webhook vs API. However, you might still not know which one is right for your needs.

The truth is, it's not always an either/or situation—many successful applications use both to create a robust, responsive system.

Think of it this way:

• APIs are like on-demand services: Perfect when you need specific information at a particular time. They're your go-to for pulling data or triggering actions when you want them.
• Webhooks are like your personal news feed: Ideal for real-time updates and automating workflows. They keep you in the loop without you having to constantly check for changes.

In many cases, using both APIs and webhooks can provide the most comprehensive solution. It's like having both a reliable assistant (API) who responds to your requests and a proactive team member (webhook) who keeps you updated on important events.

Ready to get started with APIs and webhooks?

Here's how SendGrid can help:

1. Email API: Our robust Email API lets you send emails programmatically, perfect for transactional emails or automated marketing campaigns.
2. Event webhook: Get real-time data on email opens, clicks, bounces, and more.
3. Inbound parse webhook: Receive and process incoming emails automatically.
4. REST API: Manage your SendGrid account, lists, and email data with our comprehensive REST API.

Sign up for free to see for yourself and start sending.