> Markdown version of [/videos/1581-82-bugs-i-collected-in-a-year-you-won-t-believe-made-it-to-production?t=0](https://www.wearedevelopers.com/videos/1581-82-bugs-i-collected-in-a-year-you-won-t-believe-made-it-to-production?t=0). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md).

---

# 82 Bugs I Collected in a Year You Won’t Believe Made It to Production

One engineer documented hundreds of production UI bugs. These glaring defects carry severe business risks. Discover proactive testing strategies to eliminate costly front-end leaks.

- **Speakers:** [François Martin](https://www.wearedevelopers.com/@francois-martin)
- **Event:** World Congress 2025
- **Published:** August 20, 2025
- **Duration:** 31:54
- **URL:** https://www.wearedevelopers.com/videos/1581-82-bugs-i-collected-in-a-year-you-won-t-believe-made-it-to-production

## Summary

Over nearly two years, a software engineer documented over 300 bugs encountered across various everyday production web applications, proving that glaring software defects routinely slip past quality assurance. Rather than purely backend failures, an overwhelming majority of these bugs surfaced in the user interface—from missing structural layout responsiveness to invisible text and broken dark modes—highlighting a widespread industry gap between rigorous backend testing and relatively fragile front-end validation practices.

This collection exposes how seemingly minor cosmetic errors carry severe business and security implications. For example, an unresolved template placeholder in a hotel's reception schedule caused a directly lost booking, while exposed stack traces and unfiltered client-side exceptions offer potential attackers immediate insights into server architecture and paths. The presentation highlights a wide spectrum of defects, including bizarre UI glitching, unpredictable floating-point arithmetic on e-commerce sites, silent validation failures, and unhandled null values appearing in final production rendering.

To combat these production leaks, engineering teams must implement richer preventative and diagnostic strategies. Proactive methodologies like "dogfooding" proprietary software, performing hands-on exploratory testing, and adopting strict mobile-first design can catch structural visual bugs that automated scripts inherently miss. For persistent UI friction, engineers are actively encouraged to leverage interactive heatmap visualization—tracking analytics like "dead clicks" and "rage clicks" via tools like PostHog—and to construct robust end-to-end emulation using frameworks like WebdriverIO and Playwright, ultimately ensuring smooth user experiences and securely generic production error mapping.

**Keywords:** production software defects, ui testing gaps, responsive layout design tools, unresolved templating errors, unfiltered error messages, production stack trace security, mobile-first design testing, end-to-end ui automation, webdriverio test framework, playwright browser emulation, flaky test resolution, internal software dogfooding, exploratory qa testing, heatmap click visualization, rage click analytics, silent ui validation failures, front-end bug tracking

## Chapters

1. **Bizarre software defects discovered in live production environments** (00:00) — Observing live application faults demonstrates how basic data formatting errors degrade end-user experiences.
1. **Tracking the frequency of software defects over time** (08:25) — Visualizing defect accumulation over a multi-year period uncovers unpredictable spikes in live deployment issues.
1. **Categorizing the most common production software UI defects** (10:39) — Categorizing collected runtime deviations demonstrates that superficial rendering errors outnumber complex backend logic faults.
1. **Mitigating UI responsiveness bugs via mobile-first testing strategies** (13:33) — Adopting mobile-first design and end-to-end device emulation prevents blocking UI misalignments.
1. **Addressing unpredictable UI glitches through dogfooding and monitoring** (20:59) — Leveraging dogfooding and heat map visualizers helps catch chaotic rendering errors before users experience them.
1. **Preventing unresolved templating errors with automated string assertions** (27:03) — Implementing unit tests to verify placeholder resolution avoids displaying broken strings to end users.
1. **Securing unfiltered error messages against infrastructure information leaks** (29:41) — Hiding production stack traces and mapping internal backend errors to generic user messages closes critical security vectors.

## Related Moments

- [Overcoming production bugs with zero-touch debugging automation tools](https://www.wearedevelopers.com/videos/1175-startup-presentation-dealing-with-the-bug-mafia) (from "Startup Presentation: Dealing with the bug Mafia")
- [Managing vulnerabilities in production environments through bug bounties](https://www.wearedevelopers.com/videos/53-securing-your-web-application-pipeline-from-intruders) (from "Securing Your Web Application Pipeline From Intruders")
- [Preventing catastrophic failures in high-stakes software](https://www.wearedevelopers.com/videos/720-when-testing-just-doesn-t-cut-it) (from "When testing just doesn’t cut it")
- [The impact of minor user interface bugs on trust](https://www.wearedevelopers.com/videos/540-let-s-get-visual-visual-testing-in-your-project) (from "Let's get visual - Visual testing in your project")
- [Embracing failures and analyzing high-profile software engineering mistakes](https://www.wearedevelopers.com/videos/423-the-software-bug-all-stars-and-what-we-can-learn-from-them) (from "The Software Bug All Stars - and what we can learn from them")
- [Financial and human costs of software defects](https://www.wearedevelopers.com/videos/85-how-will-artificial-intelligence-change-the-future-of-software-testing) (from "How will artificial intelligence change the future of software testing?")

## Related Articles

- [Dev Digest 119 - ❤️ === ❤️](https://www.wearedevelopers.com/magazine/454-dev-digest-119)
- [Dev Digest 129 - Now that's what I call private data!](https://www.wearedevelopers.com/magazine/468-dev-digest-129-now-that-s-what-i-call-private-data)
- [Dev Digest 139 - Soft and hard queries](https://www.wearedevelopers.com/magazine/487-dev-digest-139-soft-and-hard-queries)
- [Dev Digest 131 - AI'm not sure about OSS](https://www.wearedevelopers.com/magazine/472-dev-digest-131-ai-m-not-sure-about-oss)

## Related Jobs

- [Engineer, Offensive Security Organization](https://www.wearedevelopers.com/jobs/ext/1992296-engineer-offensive-security-organization) at **Twilio**
- [Senior Web Designer, Growth](https://www.wearedevelopers.com/jobs/ext/102722-senior-web-designer-growth) at **Intercom, Inc.**
- [Senior Software Engineer, Enterprise Products](https://www.wearedevelopers.com/jobs/ext/1841248-senior-software-engineer-enterprise-products) at **GitHub**
- [Senior Software Engineer, Client Apps Platform](https://www.wearedevelopers.com/jobs/ext/1773893-senior-software-engineer-client-apps-platform) at **GitHub**
- [Remote Senior Full-Stack Engineer](https://www.wearedevelopers.com/jobs/ext/683045-remote-senior-full-stack-engineer) at **Edge Impulse**
- [Remote Senior Full-Stack Engineer](https://www.wearedevelopers.com/jobs/ext/679408-remote-senior-full-stack-engineer) at **Edge Impulse**