Your app works. Users love it. Growth is strong. Until suddenly, it’s not. Engagement drops. Complaints rise. Support tickets pile up. Users churn. You scramble to figure out why—and by the time you do, the damage is done. What happened? Poor app performance—one of the biggest silent killers in SaaS.
Many founders ignore stability and performance in the early days. And it makes sense: investors care about traction, not backend optimizations. New features drive excitement while fixing hidden performance issues feels like a distraction. As long as everything “works,” it’s easy to put maintenance on the back burner. But here’s the reality: performance isn’t just a technical detail—it’s a growth multiplier. And when ignored, it can slowly erode user trust, damage retention, and kill momentum.
In this article, we’ll break down the hidden costs of poor performance, why founders keep making the same mistake, and how to fix it before it’s too late.
Let’s dive in.
Why Do Founders Ignore App Performance?
A few years back, we were working with a founder who was in the heat of a hyper-growth phase. She was juggling a million things: expanding her marketing funnel, raising money, courting strategic partnerships, working through never-ending feature updates, and still trying to maintain some semblance of a life outside the office. Whenever someone mentioned “stability” or “performance,” she would kindly wave them off and say something like, “Yes, yes, we have a maintenance day scheduled soon” or “We’ll handle that as part of KTLO.”
KTLO (“Keep The Lights On.”) is the tech slang some teams use to label all the backend work that keeps apps running smoothly. Others might call it technical maintenance, code debt reduction, or the dreaded “engineering overhead.” One way or another, these names refer to tasks whose value is not easily noticed by users and prevent the team from building new features. Yet, ironically, it’s often those tasks that provide the foundation on which all those big, publicized functionalities are built. Without that solid foundation, the house becomes a building made of cards, destined to collapse quickly.
Many startup founders aren’t typically trained in software engineering. Many are visionaries or business-minded individuals. Their job is to see the big picture, connect the dots, and hustle out a minimum viable product (MVP) before the window of market opportunity for their idea closes shut. In that environment, focusing on growth, user acquisition, or revenue can completely cover any concerns about performance or reliability. After all, what good is a perfectly functioning product if you launch too late?
Founders often measure success by how quickly they can capture target market share and/or product market fit. High performance and stability, while obviously critical, might feel secondary to user signups, sales, or daily active users. Investors ask about traction, not your latest refactoring efforts and the number of bugs fixed. Thus, It’s perfectly normal to put performance improvements on hold when growth is the main and often only focus.
Another factor is budget constraints. Early-stage companies typically operate with a limited pile of funds to work with. Every hour of developer time spent on optimizing backend code or rewriting front-end architecture is an hour not spent on building a new feature that might attract more users or customers. As already mentioned, many such improvements are invisible to the user. Nobody will get excited or even understand if your team puts, “We rewrote half our code so you’ll have fewer crashes!” in the update notes.
Who can really blame the founders, especially when it all runs as smoothly as butter? Modern cloud platforms and frameworks are surprisingly forgiving in the early stages. You can quickly spin up a prototype that handles small user volumes just fine. You might even go through a few thousand signups without noticing major performance issues, which can lure you into a false sense of security.
It’s only when you start scaling that the cracks become more apparent: random crashes, slow load times, and eventually downtime that your customers can’t ignore. By then, you’ll face a difficult choice: freeze feature development to fix mounting problems or risk your user experience deteriorating further. It’s when the founder’s devs look at him/her with smug faces and say: “We’ve been warning you for months, but you wouldn’t listen”.
Despite this being a fairly predictable scenario, it’s far too common. Let’s look at how poor performance can manifest and how each problem can silently sabotage your product’s future.
What Can Go Wrong?
Below is an in-depth look at the most common types of performance and stability issues plaguing growing products.
1. Downtime
Downtime is nothing more than a period during which your app or service is completely inaccessible to users. Sometimes it’s a matter of minutes, like a quick server reboot, but it can also go on for hours or even days. This usually happens due to catastrophic failures or severe scaling issues. Downtime is the most obvious and public performance issue, that hits the users (and your team) the hardest.
Likelihood & Impact
Downtime will be rare early in your product’s life. Cloud providers often offer built-in resilience, so small teams can stay afloat without much specialized knowledge. But as you scale, or if you store more complex data, the risk of downtime increases. A single well-placed bug or surge in traffic can topple your entire service. When your app is down, you lose user trust by the second. Existing customers may also question the reliability of your entire offering, which can lead to account cancellations or negative reviews. A single, seldom downtime will likely be harmless, but if it keeps happening, it can even drive your app to literal ground.
How Long Can It Be Ignored?
Downtime is the real “Critical” level of crisis. You’ll know it happened the minute your users start emailing or tweeting in frustration. Realistically, you can’t ignore it at all. Even short outages can lead to lost revenue, especially if you’re in e-commerce or a consumer-facing service. Think about Slack going down on a Monday morning: People instantly migrate to other messaging tools, complain on social media, and question Slack’s reliability. Slack can realistically afford it, as users need it so much, they will start pouring in the moment the product is back online. Your start-up app might not be as lucky.
Prevention Recommendations
- Implement Redundancy: Have failover systems or servers in different regions. This is a non-negotiable for any app with mission-critical uptime requirements.
- Monitoring & Alerting: Tools like PagerDuty or AWS CloudWatch can warn you before a full crash occurs. Automated alerts give you a chance to fix minor issues before they escalate. Ideally, you want to know about downtime before your users start noticing.
- Regular Stress Testing: Periodically test how your system performs under peak load conditions. Knowing your limits helps you plan for future growth.
- Follow trends and innovations: Sometimes hackers will figure out new ways of bringing your product down, often just because they can. If you know what can happen, you and your server host can be better prepared.
2. Crashes
A crash happens when a user’s session abruptly dies or the app closes on a device for no apparent reason. This can be due to unhandled exceptions, memory leaks, or compatibility issues with certain operating systems or devices. While partial, device-specific crashes are less severe than full-scale downtime, they can be just as damaging to the user’s experience. You can say that downtime is a serious blow, while frequent crashes are death by a thousand cuts.
Likelihood & Impact
Crashes are highly likely in feature-packed apps, especially when you skip thorough QA on different device types and OS versions. Android phones are especially painful due to their variety. Crashes create an impression of instability and frustration. We have all experienced it: a few things are more infuriating than losing progress in the middle of an order or video game level. Unresolved, these crashes will lead to app store ratings plummeting, negative word-of-mouth, and bloated churn levels.
How Long Can It Be Ignored?
Small, infrequent crashes might slip under the radar for a while, especially if your user base is still modest. There’s a temptation to say, “It only affects 1% of users; we’ll fix it later.” However, in a real-world scenario, that 1% can be your most vocal or high-value customers and mean dozens, not hundreds, of thousands of users. Plus, it will likely only going to get worse. In short, you can’t postpone addressing recurring crashes indefinitely without eventually seeing users leave in mass.
Prevention Recommendations
- Automated Crash Reporting: Always integrate a tool like Sentry or Crashlytics. Keep an eye on crash frequency by device, OS version, or other parameters.
- Regular Testing: Each time you introduce a new feature, run regression tests across various environments. Even a small code change can trigger unforeseen crashes. It’s especially advised to perform automated and integration testing.
- Prioritize Crash Fixes: If you see crash frequency trending upward, put the feature backlog on hold and fix those issues. Trust me, it’s worth the trade-off. At the same time, the “No crush” policy is a step too far, keep common sense here.
3. Bugs
Everyone has seen a bug in some product: a broken button, incorrect logic, UI misalignment, or erroneous calculations. Bugs range from trivial (a minor UI glitch) to mission-critical (double-charging a user’s credit card). While many product leaders accept some level of bugs at launch, the real question is how you handle them over time.
Likelihood & Impact
It’s almost certain you’ll have bugs in your software, there is no escaping it. No matter how skilled the team is or how thoroughly you test. You will also likely fix big offenders quickly, as they stick out. The silent danger here is the cumulative effect of ignoring smaller bugs, which might eventually compound into slowness, crashes, and even downtime.
How Long Can They Be Ignored?
Some minor, unlikely-to-happen, or harmless, bugs might stay in the backlog forever. Realistically, fixing them will be a waste of time. However, if you consistently deprioritize bug fixes, your product’s stability suffers piece by piece. Users come to anticipate “weirdness” in your app. They tolerate it until they don’t. Once that happens, it’s game over for your carefully built but poorly maintained product.
Prevention Recommendations
- Set a Bug Threshold: If your bug queue crosses a certain number or severity, shift engineering focus to bug-squashing sprints.
- Organize a Triage System: Not all bugs are equal. Classify them by impact: critical, high, medium, or low. Ensure your team promptly addresses top-severity items.
- Continuous QA: Don’t wait for major releases. Have testers or QA specialists regularly probe the app, even if it’s just to confirm existing functionality still works.
- Require more for new releases: Why 0 bugs in the whole product is a clear overkill, you should expect perfect quality from any new release. It’s like tolerating a level of toxicity in water with a complete ban on pouring additional pollution.
4. Poor Scalability
Scalability issues show up when your user base or data volume grows beyond what your architecture can handle. It might be experienced as extremely slow load times, partial outages, or the system simply refusing to work (aka timeouts). Common reasons include exponential data growth, large user spikes, or poorly optimized database queries.
Likelihood & Impact
Scalability problems often appear as your usage crosses a certain number, i.e. going from 10,000 daily active users to 100,000. The transition from an MVP to a fully-fledged product often reveals hidden inefficiencies. The cost to fix deeply ingrained scalability issues can be enormous, sometimes requiring a partial or full rewrite of the backend. Failing to address them in time can kill your viral momentum, as new users bounce from the slow or unresponsive app. The most painful example we recall is the release of the video game Diablo III, which was initially down for several days upon release as servers were never built to the overwhelming numbers of players that showed up to play on the game’s launch day.
How Long Can It Be Ignored?
If you’re in a super-niche market, you can skate by on minimal scaling for some time. But the moment your growth starts to accelerate, neglected scalability becomes a burning platform. If you’re raising funds, you can bet savvy investors will ask about your scaling plan. Ignoring it might cost you the next round, or cause your user adoption to plateau as newcomers experience a sluggish product.
Prevention Recommendations
- Start the product with scalability in mind: Use microservices or containerization early so you can launch more instances as usage grows.
- Database Optimization: Keep queries efficient and index critical columns. Archive or offload rarely accessed data.
- Name a code architect: If your code and database structure has a scalability patron, you are unlikely to ever hit that wall.
- Load Testing: Tools like Locust or k6 can simulate high-traffic scenarios. Regularly test your app’s behavior at multiples of your current user load to anticipate pain points.
5. Slow Performance
Your app might technically work, but it lags or feels clunky. Screens take forever to load or freeze for several seconds. User experience becomes user frustration and can be compared to yet another death by a thousand cuts.
Likelihood & Impact
Slow performance is extremely likely once you add layers of features without testing for performance. According to a study by Google, 53% of mobile website visitors leave a site that takes longer than three seconds to load. While that stat references websites specifically, it speaks to the broader attention thresholds of mobile users. It is a well-known fact that the longer the mobile app loads, the more users will kill or even uninstall it during the first launch
How Long Can It Be Ignored?
Occasionally, you can get away with suboptimal performance if your product offers a unique, high-value feature, at least until a better-optimized competitor appears (Remember Internet Explorer?). For 99% of other apps, any avoidable slowness is basically choosing to have fewer clients.
Prevention Recommendations
- Profiling: Use tools like Xcode Instruments for iOS, Android Profiler for Android, or web performance profilers to identify bottlenecks.
- Caching: Speed up data delivery by caching frequently accessed content.
- Front-End Optimization: Optimize images, scripts, and data parsing. A lean front end can drastically improve user experience.
6. Building with High-End Hardware in Mind
When development is mostly done on advanced machines or top-of-the-line smartphones, it’s easy to forget that not all your users have similarly powerful hardware. An app that runs smoothly on a brand-new Samsung S25 Ultra might choke on an older Xiaomi phone. This creates an uneven experience where some users have a flawless journey while others struggle.
Likelihood & Impact
This issue often arises when your product team resides in high-tech hubs with fast internet and the latest gadgets. If your target audience is broader your product’s performance can degrade quickly on these less capable setups. The impact? You might lose entire demographics or markets, as your app simply becomes unusable to them.
How Long Can It Be Ignored?
In the short run, you can ignore it if you assume your target audience is well-off or tech-savvy. But as you try to scale globally or even just beyond your initial niche, you’ll realize you’ve locked out many potential customers. It’s a silent opportunity killer.
Prevention Recommendations
- Test of a wide range of devices: Explicitly test your app on low-end or mid-range devices and varied network conditions.
- Feature Toggles: Offer light or optional versions of computationally heavy features.
- Limit app accessibility: Enable the download of your app only for OS systems and devices that you know will support optimal user experience.
7. Security Loopholes
While security is not usually classed under “performance,” it’s part of the broader “stability and reliability” conversation. Ignoring security aspects can lead to data breaches, hacking incidents, or other incidents that break user trust.
Likelihood & Impact
As your user base grows and you store more sensitive data, your app becomes a more and more tempting target for cyberattacks. Even a single successful hack can cause serious reputational damage, trigger regulatory oversight, and mass user exodus.
How Long Can It Be Ignored?
Unlike a minor bug, you can’t afford to ignore even a minor security issue for long. The bigger you get, the higher the stakes. This is perhaps the most invisible aspect
Prevention Recommendations
- Dedicated, Specialized Testing: Periodically hire ethical hackers to probe for weaknesses.
- Secure Architecture: Use encryption for data in transit and at rest. Keep dependencies up to date and enforce secure coding practices.
- Access Control: Maintain minimal necessary privileges for staff and robust role-based access for user accounts to limit potential damage.
Conclusion
Most founders don’t think about app performance until it’s too late.
At first, everything seems fine—your product works, users are signing up, and growth is steady. But behind the scenes, silent performance issues are building up: slow load times, unexpected crashes, frustrating bugs. Then suddenly, users start churning, complaints flood in, and acquisition costs skyrocket.
By the time you notice, the damage is already done.
The good news? You can fix this before it becomes a crisis.
What’s next?
- Identify your weak spots – Are you already seeing signs of performance issues?
- Take action before users churn – Don’t wait until support tickets pile up.
- Get expert help – We’ve helped SaaS companies eliminate crashes, downtime, and slow performance—so they can scale without limits.
