Webhooks: A Mindset Change for Batch Jobs
Tags: webhook, batch, realtime, callback
Published: 2024-05-15 17:29:14

<u>**Introduction**</u>
Hidden beneath the surface of many organizations lies a dirty little secret: the staggering amount of code, data, and computing power dedicated to batch jobs. It's a problem that's often overlooked, yet it significantly impacts efficiency, agility, and the overall customer experience. What's the strategy for moving away from these resource-intensive batch processes?

While not all batch jobs can be eliminated overnight, there's a specific subset that we can tackle right now. This article will explore how webhooks offer a powerful alternative, enabling a shift towards real-time or near-real-time communication that can revolutionize how your systems operate.

**What are Webhooks?**
![Webhooks](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/bld2sbsgbae2tzzw832k.png)
A webhook is a user-defined HTTP callback that is automatically triggered when a specific event happens. It enables one application (System A) to send real-time information to another (System B) over the web. System A provides System B with a unique callback URL, which System B stores securely. When the specified event occurs in System A, it sends an HTTP POST request containing relevant data to the stored callback URL, triggering a response in System B. Think of it as a kind of automated message delivery system where System A says, "Hey, something just happened here, and I want you to know about it!" and then sends a notification to System B.

**Wait, what about Polling?**
Before webhooks, one approach was polling – where System A repeatedly checks System B for updates. This is inefficient, especially when System B doesn't always have new information. Think of it like constantly calling a friend to see if they're ready, even though they told you they'd call you back when they are. Webhooks are that "call you back" mechanism.
 
**The Accidental Rise of Batch Jobs**
A class of batch jobs arose to work around polling's limitations. System B would gather messages and send them to System A in batches, but this led to data inconsistencies and multiple versions of the same data across systems. These batch jobs weren't a deliberate design choice, but a compromise due to technological limitations. Now that we have webhooks, we can often eliminate these types of batch jobs.

**Webhooks: The Modern Alternative**
![Webhook vs Polling (credit bytebytego)](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/sb2h2wk6hvaktthrjd87.png)
Webhooks offer a more elegant solution. The goal should be to process and respond to messages as quickly as possible. If a synchronous response isn't possible, use asynchronous processing – without accumulating messages into batches. Webhooks excel at this, whether you choose reliable serverless options or direct HTTP webhooks. The key is to shift the mindset away from batch accumulation and towards real-time or near-real-time processing.

**Overcoming Webhook Challenges**
Webhooks aren't perfect. Their main weakness is "brittleness": if System A is down when System B sends a webhook, the message can be lost. Retries on System B's side can lead to duplicate messages, causing problems if the webhook's action isn't idempotent (safe to repeat). To overcome these challenges, ensure your webhook actions are idempotent. For mission-critical messages, consider using a message broker like Kafka alongside your webhooks. This guarantees delivery and eliminates the risk of lost or duplicate messages.

**When Batch Jobs Still Make Sense**
There are cases where batch jobs are the right tool – for example, processing large datasets that don't need immediate action. However, it's crucial to carefully evaluate whether a batch job is truly necessary or if webhooks can provide a more efficient solution.

**In Summary:**
Webhooks empower you to simplify your systems, enhance data consistency, and streamline processes. By shifting away from batch-oriented thinking and embracing real-time (or near-real-time) communication, you can achieve a new level of efficiency and reliability. Ultimately, this seemingly small change can significantly improve the customer experience. In today's fast-paced world, nobody wants to wait – we all want results yesterday.