High Traffic Surges Got Your Website Down? Here’s Why

A surge in traffic is, in many ways, a dream for any website. After all, more traffic means more customers and more sales.

However, you can sometimes do your job too well when your successful marketing campaign brings surges of traffic, causing your website or app to slow down and even crash. Nothing is more heartbreaking than seeing your website or app fail when you have the most to gain.

Most blogs and articles state that traffic-induced crashes as something that can happen. But if you don't understand how high traffic crashes a website or app, how can you expect to avoid the problem?

Here’s what you’re overlooking:

You lack resources

The main reason websites and apps continue to slow down and, ultimately, crash under load is the disparity between traffic levels and the capacity of your website's infrastructure.

The system requests made by your customers on your website overshadow its processing capacity resources and any third-party systems involved in the customer journey.

As a result, your website performance suffers.

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Your website has bottlenecks

Not all requests made by your customers are equal. Some are more complex or demanding than others. Thinking about capacity in terms of concurrent users just doesn't cut it.

Imagine you're at your local supermarket, which has room for many shoppers if they're spread throughout the store. The main bottleneck exists at the checkout counters, served by several cashiers. When there's only a handful of customers buying groceries, cashiers can keep the lines moving and the shoppers happy.

Suddenly, there's a mad dash for the checkout counters. The number of shoppers in the store hasn't changed, but now the cashiers are overwhelmed. Customers are getting annoyed, and the cashiers can't cope — a lose-lose situation for everyone involved.

unhappy shoppers

Like the throngs of shoppers all racing for the checkout counters, high online traffic puts pressure on your systems, creating bottlenecks. It is these weak points that serve as limiting factors on website capacity.

You face unpredicted traffic surges

Let's look at an example of the steps behind a website crash using one of someone that has a knack for causing websites to fail — Meghan Markle.

She has a devoted group of followers who pay close attention to everything she wears. Her fashion choices crashed an online retailer's site twice in 2018. It's known as the Meghan Effect.

Let's look at a customer journey for Meghan Markle's latest outfit and the behind-the-scenes legwork the site's database is doing.

Customer action
Sees Tweet about a dress, clicks on a link to designer's home page
Loads images and browser script
Types name of the dress into the search bar
Complex search functions must find all items that match the search term(s), accounting for misspellings, product categories, features, etc.
Browses list of products from search and clicks the dress
Loads images and browser script. Shows up-to-date inventory information.
Adds dress to cart
The inventory system must update to avoid over-purchasing and stay in sync with all other users.
Proceeds to purchase by creating a guest account
Sync dynamically entered information with the membership database
Enter shipping information
Send and receive requests from shipping plugins, like address verification and shipping costs calculator
Enter payment information
Send dynamically entered information to payment gateway and awaits confirmation
Sees order confirmation
Inventory system updates stock remaining

Each step in the customer journey adds further pressure on the site’s infrastructure. Bottlenecks begin to appear where processing power is fully extended, and additional requests cannot be served.

Website visitors will experience this in the form of a website slowdown and eventual crash. So much for getting the royal treatment.

(Find a more technical discussion from a developer’s perspective here).

When does high traffic crash a website?

There are three major scenarios when high traffic can crash your website or app.

1. The Unexpected Traffic Spike

This surge can occur because of the Meghan Effect, bot traffic, or an overly successful marketing campaign your website was unprepared for.


Figure 1. When your email newsletter campaign is an unexpected hit. (Source)

2. Big Name Sales

Big name sales like Black Friday and Singles’ Day can drive traffic levels 30 times higher than a normal day. But even with specific start-time events, the timing and level of online traffic spikes can be hard to predict.


Figure 2. A customer using Queue-it's virtual waiting room experienced several peaks of end-users in queue per minute during Black Friday.

3. Limited Quantity of Products

A collection of releases or campaigns when a limited quantity of products is made available can draw eager buyers to your website before the products drop. This opens the possibility that your site will crash before the sale even begins.

What can I do to prevent website crashes?

Don’t despair: website failure doesn’t have to be an unavoidable part of running overly successful campaigns.

Here are three questions you should ask yourself to minimize the risk of high online traffic crashing your site.

1. Have you optimized your website’s performance?

Identify heavy database requests on your website, and limit the number, size, and complexity of those requests. There are many ways to build performance into your website.

Use a content distribution network (CDN) to free up your servers to focus on dynamic content. Compress images and upload them at their intended display size. Minimize the use of plugins where possible.

2. Have you done load testing?

Load testing is one of the best preparations you can make for web traffic peaks. The aim is to help you understand how your website will perform when visitors hit it in big numbers.

Remember to set aside adequate time for load testing, as each test will reveal new bottlenecks that need fixing. At the same time, while it’s important to get started early, it also doesn’t make sense to test before the customer journey is complete.

Further, be sure to notify your hosting provider that you’re load testing. Many providers consider an unauthorized load test a violation of the terms of service.

3. How are you monitoring your website performance?

With the stakes so high and many factors that impact optimal performance, continuously monitoring your website helps prevent outages or broken pages across your most important user journeys. Adding a reliable performance alert system can quickly identify any problems, when and where they occur, and how to fix them.

To find out how Keysight's Eggplant can monitor your website and prevent any downtime, read our product guide or contact us for a free trial.