If you've ever set up conversion tracking on a single-page application (SPA), you know how frustrating it can be when conversions just… vanish. You see the user click the button, fill out the form, maybe even get a "Thank you!" message—yet your analytics platform shows nothing. This isn't just annoying; it's a business problem that can completely mess up your attribution and leave you making decisions based on incomplete data.

Here's what's really going on and how to track down those missing conversions.

Why SPAs break tracking in the first place

Most tracking tools were built back when websites worked differently. Every important action meant loading a new page, and tracking code could reliably fire on those page loads. SPAs don't work that way at all. They load content dynamically with JavaScript, creating smooth user experiences but absolute headaches for anyone trying to measure what's actually happening.

Your tracking pixel is basically waiting for a page load event that never comes. It's like waiting for a train that's already left the station.

When a user converts in an SPA, here's what typically happens: they click a button or submit a form, JavaScript processes everything without refreshing the page, the UI updates to show success, maybe the URL changes, and your tracking code just sits there completely oblivious to what just happened.

Where to actually look when things go wrong

Event listeners and timing issues Your tracking needs to listen for the right events at the right time. Instead of relying on page loads, you need to hook into form submissions, button clicks, custom JavaScript events, or DOM changes that indicate a conversion occurred.

The tricky part is timing. SPAs often load tracking scripts asynchronously, which creates race conditions. If someone converts before your tracking code is fully loaded, you'll miss it entirely. This happens more than you'd think, especially on mobile.

URL changes without page reloads Many SPAs update the URL using pushState or replaceState without actually reloading the page. If your analytics tool isn't configured to recognize these "virtual" pageviews, it'll miss critical conversion steps. You might need to manually trigger pageview events when the URL changes.

Data layer problems If you're using Google Tag Manager, your SPA needs to actively push conversion data to the data layer at the exact moment conversions happen. This isn't automatic—your developers need to add specific code that says "hey, a conversion just occurred" and includes all the relevant details.

AJAX form submissions Traditional forms reload the page when submitted, giving tracking code a clear moment to fire. AJAX submissions happen silently, so you need to explicitly trigger tracking events in your form submission handlers. This is probably the most common issue I see.

How to actually test your setup

Skip the guesswork and get technical. Open your browser's developer tools and walk through the conversion process yourself. Go to the Network tab, clear it, then complete a test conversion while watching the network requests. Look for tracking calls to Google Analytics, Facebook Pixel, whatever you're using. If you don't see the expected requests, your tracking isn't firing.

Most tag management platforms have debug modes that show you exactly when tags fire. Use these to verify tags trigger at the right moments, check that the correct data is being sent, and identify timing issues.

Here's something that helped me catch a bunch of issues: set up logging to capture when conversions should fire but don't. This helps you identify patterns—maybe conversions only fail on certain browsers, device types, or specific user flows.

Common ways this stuff breaks

Third-party plugins and widgets Chat tools, payment processors, and other popular plugins often don't play well with SPAs. They might override your form submission handlers, load their own conflicting tracking code, or create iframes that break your event listeners.

Dynamic content loading If conversion elements are loaded dynamically (like through modal windows or lazy loading), event listeners attached to those elements might not exist when the page first loads. You need to use event delegation or re-attach listeners when content changes.

Cache and session weirdness SPAs can create caching situations where old tracking code persists even after you've made changes. Always test in incognito mode when debugging, and clear cache completely. I've wasted hours debugging "broken" tracking that was actually just cached.

Scripts loading too late The user converts before your tracking tag is ready. This is especially common on fast connections or when users navigate quickly through your app.

Some advanced stuff that actually works

Instead of fighting with existing tracking tools, implement custom events that fire at key moments in your conversion flow. This gives you way more control:

// Fire custom event when conversion completes
window.dataLayer = window.dataLayer || [];
window.dataLayer.push({
  'event': 'conversion_completed',
  'conversion_value': 49.99,
  'conversion_type': 'purchase'
});

Map out every single step in your conversion process and verify tracking at each stage. Often, the issue isn't with the final conversion event but with an earlier step that's not being tracked properly.

And here's something that saves me a ton of time: if your conversion flow crosses multiple subdomains or involves third-party payment processors, make sure your tracking is configured for cross-domain tracking. Otherwise, you'll lose attribution when users move between domains.

Bottom line

SPAs make for great user experiences, but they need a completely different approach to tracking. The old "fire on page load" method just doesn't work. You need to spend time mapping out exactly when and how conversions happen in your app, then set your tracking to match that reality.

With the right setup and some careful testing, you won't miss another conversion. But it definitely requires more upfront work than traditional website tracking—there's no getting around that.