When an e-commerce site starts dragging, every second counts.
A slow-loading page is more than an inconvenience – it’s lost revenue, abandoned carts, and customer churn. Yet most teams I’ve worked with spend hours chasing obscure fixes before checking the obvious.
Over the years, I’ve developed a simple debugging playbook that solves the vast majority of performance issues in under 30 minutes. It’s not flashy, but it’s effective. Think of it like rebooting your Wi-Fi before you call IT support.
These aren’t deep cuts from the bowels of a systems engineering textbook. They’re the five things I reach for first – because they work fast.
And yet, almost nobody I talk to starts here.
Let’s fix that.
1. Check the Network First – Always
The browser’s Network tab is the fastest way to spot bottlenecks. You’ll often see one of three red flags immediately:
- Third-party scripts taking forever to load
- Massive image files (no, your hero banner doesn’t need to be 5MB)
- Requests stalling or failing silently in the background
The great thing: it’s free to do. Open Chrome > DevTools > Network > Reload the page. Sort by “Time” to find slow resources.
This takes 60 seconds to check. Do it before anything else.
2. Disable Extensions and Incognito Everything
Performance issues can be local – especially when debugging as a developer.
Browser extensions (especially ad blockers or script injectors) can:
- Interfere with site scripts
- Block resources that break rendering
- Introduce lag that users won’t experience
Before you go down a rabbit hole, check the site in a clean incognito window.
If you don’t use Incognito, it’s a real life-saver. Just open up Chrome > Three dots menu > “New Incognito Window”.
3. Set Up Real Device Testing – Not Emulated
Here’s the uncomfortable truth: your $2,500 MacBook is not how your customers experience the site.
The typical user is:
- On a mid-range Android
- Browsing with a 3G connection
- Distracted, impatient, and one click from bouncing
Use real devices with throttled connections (or use tools like BrowserStack) to replicate the environment. Many performance issues only show up under real-world stress.
If you don’t have any of these options? Chrome to the rescue again – just open it up > DevTools > “Network” tab > Throttle to “Regular 3G”.
Tip: Also use “Device Mode” to simulate mobile screens.
Want real-device testing for free? Use:
4. Audit the Render Path
Slow First Contentful Paint (FCP)? Time to simplify the render path.
Ask yourself:
- Is JavaScript blocking the page from rendering?
- Are you loading five font files when you only use two?
- Is your page waiting on above-the-fold images?
Every millisecond adds up. Tools like Lighthouse or PageSpeed Insights will spell this out for you – if you know how to read them. Look for “render-blocking resources” and start trimming.
5. Look at the Backend Logs (Really Look)
This one gets overlooked the most – especially by frontend developers.
If page loads are sluggish after initial render, the backend is usually the bottleneck:
- Long database queries
- Overloaded APIs
- Slow server response times
Your observability stack (New Relic, Datadog, etc.) isn’t just decoration. Dive into your logs. Look for outliers. Often, it’s one or two endpoints dragging the entire experience down.
Also, free options exist (again, Chrome): Chrome’s DevTools > “Timing” tab > Look at “TTFB” (Time to First Byte)
TTFB is your backend’s pulse. If it’s high, go server-side hunting.
Why Most Teams Miss These
Because they’re simple.
And “simple” doesn’t feel satisfying when the stakes are high. There’s a false comfort in jumping to advanced techniques – CDNs, code diagnosing, Git history analysis – before ruling out the basics.
But I’ve sat in rooms where teams burned $10K in dev hours trying to solve a load issue that turned out to be… a massive uncompressed banner image.
Don’t overthink it.
The Bottom Line
Performance issues are like dropped Zoom calls. Before you blame the app, check your signal.
Before you touch a line of code, ask:
- What’s my network tab saying?
- Am I seeing this in a clean browser?
- How does it behave on a real phone?
- What’s blocking render?
- Are the logs screaming?
These five steps won’t solve everything. But they’ll solve many things. Fast.
And in this business, speed wins.
See you next Saturday.