If you're responsible for an e-commerce website, I guarantee you've been asked about, told about, or wondered about what kind of information and events you should be logging. Important things are happening all the time, and you need to know what's going on. Right? Are they bad things, good things, or “nobody cares” things?

So what do you do? Log all the things! Right?! If you've ever found yourself awake at 3:00am wondering why you decided to become a software engineer instead of [insert any job that lets you sleep during the night here], chances are it's because you decided to log everything. Having said that, guess who has two thumbs and logs all the things? This guy.

You need to focus. It’s okay to log all the things, but you need to focus your attention on the stuff that matters the most, and a simple tool for aggregating IIS logs isn’t enough. A scalable and easy-to-use service that will alert you and provide an interface for surfacing the events that matter the most is critical to ensuring a constant revenue stream and the best possible experience for your customers. Yes, there are lots of components and potential events that really matter when it comes to developing or hosting an e-commerce website. So where should you start? I’m going to break this down into the top five areas that should be the initial focus of your logging efforts. You should not only log these types of events but also put an alerting system in place so you’re aware about things that require your immediate attention.

1. Checkout

We’ll go with the lowest hanging fruit first. If you’re an e-commerce website, your job is to convert customers. Conversion means pushing your customers through the checkout funnel and completing an order. All checkout errors should be logged, and you should instantly be alerted if any part of the checkout process fails.

This seems obvious, but it’s important you focus on each minute piece of the process including:

■ Address data collection

■ Inventory availability checks

■ Payment processing (Even if you use a third-party service, you need to log any events in addition to protecting yourself from service failures – more on this later.)

■ Authentication and authorization logic

■ Shipping estimation

■ Tax calculation

... and the list goes on. Not all checkout failures will prevent your user from physically completing the checkout process if you’re doing it right, but many of them decrease the probability that your customer will complete their order. Any squeak in the cog of the checkout process can result in revenue loss.

2. Add-to-cart

You can’t place an order if you can’t add products to your shopping cart or bag. This is a huge duh(!), but there are cases where shopping cart issues are intermittent and aren't completely preventing people from adding products to their carts. The bigger danger lies in these occasional or even moderately frequent product adds that fail without your knowledge because orders continue to flow through your website. Causes might include bad inventory availability checks, bad data, or an intermittent bug that’s difficult to reproduce. Protect yourself by logging all add-to-cart failures when they occur, send out an alert, and investigate the problem ASAP. Honorable mention goes out here to logging Wish List and Favorites errors as well. These features are about customer experience, but they’re also proven winners when it comes to converting customers.

3. Online Catalog/Product Page

Your customers can’t add items to their shopping cart if they can’t find your products. Similar to adding to their shopping carts, the danger here is the intermittent problem that doesn’t always rear its head in an obvious manner. The larger your online catalog, the greater the chance you’re going to miss errors with specific product lines, markets, or other logical groups of products. Bad data is a likely suspect here, especially if you’re dealing with very old data and/or integration with legacy software that has forced you to compromise a bit on data storage constraints. In addition to product and category pages themselves, consider logging issues with suggested, related, and recently viewed products. You’re missing out on impressions and potential revenue if any of these processes fail.

4. Email Signup

Any marketing director worth their salt will stress the importance of collecting email addresses at every opportunity. Sometimes an email address is the only thing you know about a potential customer, and sometimes it’s all you need to turn a shopper into a buyer. Any break in this process should be identified and fixed immediately. If your website gets a lot of traffic, it doesn’t take much to lose out on collecting a significant number of email addresses and a significant amount of potential future revenue. The trick here is that much of your business logic for presenting email signup to customers may exist client-side. Don’t forget to catch and log those exceptions as well as server-side issues.

5. Login & Registration

Well, you want to get to know your customers much better, right? Of course you do! All the better to turn wonderful customers into wonderful repeat customers by providing additional features and more relevant content. Failures here can lead to frustration and exits from your website as well as a degradation in your ability to provide a more personalized experience. Pay attention to your authentication and authorization logic as a whole, meaning you need to go beyond evaluating simple form data submission and validation issues. Social media login errors, out-of-sync authentication and authorization cookies, and errors generated by any additional authentication checks should be logged.

I’ll wrap this up with a short discussion about third-party services. They’re not specifically called out in my top five areas listed above, but they can definitely impact the performance and user experience of your website. There’s a good chance you’re using at least one or more third-party services as a solution for different business problems your company needs solved, and it’s likely these third-party services are an integral component of critical website features. Whether you're using a third-party service for calculating shipping, sending emails, or finding and displaying the cutest cat GIF of the day, the success of your site is depending on something that’s outside your control.

Protect yourself from these services. You should know their unscheduled "maintenance" periods better than they do. Chances are you're in the position to decide which third-party services your company uses or you have significant influence over that decision. Either way, be informed as to how they perform and have data to illustrate where their services are falling short. Are they reliable and worth the eleventy billion dollars they cost, or should your company be looking elsewhere for that cute animated kitty GIF service? It’s likely you’re already protecting yourself from failures here with some fallback business logic, but make sure you’re logging and alerting yourself when exceptions occur. They can have a serious impact on your customer’s experience and could prevent shoppers from becoming future buyers. That’s especially true if these services play in the five areas I describe above (e.g. shipping, tax, payment, personalization, etc.)

And my last parting thought: The same considerations regarding third-party services apply when your e-commerce platform becomes more of a distributed solution where those distributed services and applications are your own. You will almost certainly have other performance monitoring and metrics in place for your own services, but you still need to log, aggregate, alert, and protect yourself from yourself!

ABOUT Aaron Remaklus

Aaron Remaklus is Chief Architect and Development Manager for Speedway Motors, Inc. He leads agile development teams building high availability, extensible e-commerce platforms. A Nebraska Wesleyan alumnus, Remaklus taps into a diverse background in business, marketing, training, and software development in tackling large-scale problems.