How to monitor app performance and catch critical issues before users churn

Testing an app or a new feature before launch is never enough on its own to guarantee a smooth user experience once it’s live. No matter how thorough your quality assurance (QA) process is, you can’t fully predict how every feature will function when people start using your app on various devices and under different network conditions.

When technical issues like API errors and slow load times begin to surface, you need a way to connect them to user behavior signals like rage taps and drop-offs so you know which issues to prioritize and can act quickly before users churn.

This guide outlines how to build an end-to-end app performance monitoring (apm) strategy so you can stay on top of issues. We cover which metrics to track, how to connect technical problems to user behavior, and how to prioritize fixes by impact.

Key insights 

• Monitoring should start the moment your app or feature goes live, so you can catch and fix issues before they frustrate users and affect retention

• Prioritize fixes by business impact rather than error volume alone, so you don’t spend time on low-impact issues while costly problems go unresolved

• Use a platform (like Contentsquare) that connects technical issues  to behavioral data (like pairing API errors, crashes, and load times with rage taps and session abandonment), so your whole team—not just engineering—can see the real impact of performance issues and troubleshoot them together

5 steps to set up an application monitoring strategy

App performance monitoring is the ongoing process of tracking how your live app performs day-to-day, so your team can spot issues, identify their root causes, and act fast before they frustrate users. 

Without a proactive way to track what's happening in your live app, performance bottlenecks that pre-release testing missed, like a failing API call or a broken checkout step, can go unnoticed until they've already affected conversions and revenue. 

That's what makes experience monitoring on mobile so important. Below, we cover how to build an effective application performance monitoring strategy, centered on real user monitoring, in 5  steps.

1. Choose the right metrics to track

Multiple teams—engineering, product, data, and growth—depend on app performance data to detect problems and understand their impact on users and the business. Choosing the right mix of metrics and tracking them in one place gives everyone—including DevOps—a shared view of how the app is performing, so you can agree on what needs fixing and in what order.

Start by defining the core metrics that matter across teams, for example:

• Crash rate: the percentage of sessions where your app stops working unexpectedly, which helps you spot unstable builds or OS-specific issues quickly after a release

• API error rate: how often network requests fail, which reveals where backend outages, broken integrations, or third-party dependencies are disrupting user workflows

• Screen load time: how long each screen takes to become usable, which indicates latency, rendering, or data-fetching bottlenecks that can contribute to abandonment

• Network request performance: how fast your endpoints respond and how often they fail, which helps you figure out whether slowness is on the app side, the server side, or the user's connection through distributed tracing

Decide on the level of detail you need when setting up monitoring. The right mobile analytics tools let you track errors for a high-level view, or by specific screen groups to pinpoint exactly where problems affecting your application’s health are occurring. They also let you segment your data by device, user group, and app version, so it’s easy to spot whether an issue affects all users or just a specific subset, like users on older Android versions.

💡 Did you know? Contentsquare’s Dashboards tool lets you monitor API  and crash errors by specific screen groups. You can track metrics like the number and percentage of sessions with errors, the number of users affected, and see how error rates trend over time—up to 90 days. Segment by device and user group to isolate where problems are hitting hardest.

Contentsquare's Dashboards for mobile apps let you monitor error trends over time, identify spikes, and drill into which errors contributed to them

2. Identify key user journeys to monitor

Monitoring every screen and flow with the same level of attention makes it harder to separate minor issues from the ones that actually affect users and your business. 

Focus on the journeys tied to your most important business outcomes—where performance issues are most likely to hurt conversion, retention, revenue, or trust. For example, a subscription app would prioritize the sign-up and payment flow, while a banking app might focus on login and transaction flows first.

From there, expand to high-traffic paths where friction would affect the most users, even if those journeys aren’t directly tied to conversion. For instance, a laggy dashboard in a fintech app may not be part of the purchase flow, but if users rely on it every session, friction there will still affect engagement and retention.

Pro tip: use Contentsquare’s Journey Analysis tool to see how users move through your app and where they run into friction. For example, use the Reverse Journey button to trace their steps backward from an exit screen and understand what happened before they left. 

For example, NatWest used Journey Analysis on their mobile app to identify a high exit rate on their youth savings product page. Further analysis showed users were dropping off before reaching the ‘Apply Now’ button, which was hidden below the fold on some devices. The team A/B tested a variant without the hero image and with clearer benefits and interest rate information upfront, which resulted in an uplift in visitor-to-application completion rate.

NatWest's Journey Analysis view showing user paths and exit rates on the youth savings page

3. Connect technical signals to user behavior

Knowing that an API error rate spiked or a screen is loading slowly tells you something went wrong on the technical side. 

But to understand whether users were actually affected—and how—you need to pair that technical data with behavioral signals like rage taps, session abandonment, and drop-offs. Combining both gives you the full picture of what happened and how it's affecting the user experience and critical business metrics like conversion, retention, and revenue. 

For example, an API error during checkout paired with a spike in rage taps on the payment button suggests users are trying to complete a purchase but can’t. Or if a screen takes five seconds to load and drop-off rises at that step, the delay is likely pushing users to leave.

Did you know? Contentsquare's Error Analysis tool natively detects API errors—like failed network requests—and app crashes. 

For each error, you can see how many sessions were affected, how the error rate has changed over time, and which screens are impacted most. Use Error Explorer to search across all errors, filter by API status code or error type, and sort by impact on your KPIs. 

Then jump straight into mobile session replays to see exactly what happened before, during, and after the issue occurred, which gives you technical details and the behavioral context in one place. You can also create a Jira ticket directly from the error details so developers get the full context without switching tools.

Contentsquare's Error Analysis side panel shows the impact of each error, how it's trending over time, and lets you jump straight into Session Replay to continue your investigation

4. Set up real-time alerts to trigger as issues happen

Real-time alerts help your team catch urgent issues as they occur, so you can respond before the problem affects more users. But not every issue needs that level of urgency. The key is knowing what needs immediate action and what's better monitored over time.

For example, a sudden spike in crash rate after a new release warrants an immediate alert because it can block users from completing key actions. 

Focus your alerts on the journeys that matter most, like sign-up, checkout, or core feature flows. For issues that don't need an immediate response, track them in your analytics dashboards instead, so you can spot patterns without being overwhelmed by notifications.

Pro tip: set up Contentsquare's real-time alerts to monitor error rates on your mobile app every five minutes and get notified automatically when error rates spike beyond the expected range. 

This setup is especially useful during a new app release, a major feature rollout, or high-traffic periods like Black Friday. You can also drill down into any alert to see how error rates evolve over time and check whether the spike exceeded the expected range.

Contentsquare's real-time alerts track error rates and notify your team when anomalies exceed the expected range, with options to notify you via email, Slack, or Microsoft Teams

5. Prioritize fixes by business impact

Not every issue deserves the same level of effort—some have a much bigger impact on users and business outcomes than others. 

Without a clear way to rank problems by business impact, like lost conversions, missed revenue, or affected sessions, teams can end up fixing noisy but low-impact issues while the ones doing real damage stay unresolved.

To prioritize effectively, look at how many users were affected, where in the user journey the issue occurred, and the likely impact on conversion or revenue. For example, an API error affecting 500 sessions during checkout is more urgent than one affecting 5,000 sessions on a settings screen because the business risk is higher.

Pro tip: use Contentsquare's Impact Quantification capability to prioritize fixes by their actual business cost. Compare segments of users who experienced an issue against those who didn't to see the difference in conversion rate, missed revenue, and lost conversions. 

You can also view traffic distribution by app version, OS version, and network to isolate which users are most affected. 

Once a fix is deployed, compare before-and-after metrics for the affected flow to confirm that both the technical issue and the user experience actually improved.

Contentsquare’s Impact Quantification helps you compare user segments, quantify missed conversions and revenue, and prioritize fixes by business impact

For example, BFL Group used Contentsquare’s Journey Analysis and Impact Quantification to analyze its mobile product detail pages. The team noticed that mobile users were bouncing from PDPs at a high rate and found that they were more likely to convert when they visited another product page first. The team added a ‘Shop similar styles’ section and used Impact Quantification to measure the results. 

The result? Mobile PDP bounce rates decreased by 2.18%, exit rates fell by 9.41%, conversion rates rose by 6.51%, and the change was projected to add +102K USD in annual revenue.

Make app performance monitoring part of your workflow

App performance monitoring works best as an ongoing loop, not something you set up once and only revisit after users start complaining or metrics take a sudden dip. 

Contentsquare helps you run this loop in one place. Use Dashboards and real-time alerts to catch issues early, Error Analysis and Session Replay to understand what went wrong and how users were affected, Journey Analysis to see which flows are hit hardest, and Impact Quantification to measure the business cost and prioritize what to fix first.  This way, fewer issues reach your users, and you can build better mobile customer experiences that drive retention and revenue.

FAQs about app performance monitoring