DEVELOPMENT
How to investigate ecommerce problems before changing code
Logs, New Relic, CDN data, HAR files, PageSpeed, analytics and code inspection together give a far better diagnosis than rewriting components straight away.
By VISIBI Engineering team·Reviewed by Saeed Ak, Co-founder & CTO·Updated 29 September 2026·8 min read
QUICK ANSWER
Logs, New Relic, CDN data, HAR files, PageSpeed, analytics and code inspection together give a far better diagnosis than rewriting components straight away.
FROM OUR ENGINEERING WORKREAL CASE
Across many incidents, combining production logs, New Relic, CDN data, HAR files, PageSpeed and code inspection gave a much stronger diagnosis than immediately rewriting components.
KEY TAKEAWAYS
✓The fastest fix comes from the right diagnosis.
✓Combine several data sources before deciding.
✓Reproduce the issue before changing code.
STEP BY STEP
Our diagnosis process
1Define the symptom
2Gather logs, traces & HARs
3Form a hypothesis
4Reproduce
5Fix root cause & verify
The evidence toolkit
- Application and server logs
- APM traces (New Relic)
- CDN and WAF logs (Fastly, Cloudflare)
- Browser HAR files and console errors
- PageSpeed and CrUX data
- Analytics funnels
- Code and config inspection
A simple process
Define the symptom, gather evidence, form a hypothesis, reproduce, fix the root cause and verify in production.
Common mistakes to avoid
✕Starting to build before requirements and success metrics are clear
✕Not owning your code, repositories and accounts
✕Skipping automated tests to save time
✕Choosing technology the market can’t hire for
HOW VISIBI CAN HELP
How we help with development
01DiscoveryClear scope, architecture and estimates before code is written.
02Build in sprintsWeekly demos so you see progress and can change direction.
03Test & releaseAutomated tests and CI/CD for safe, frequent releases.
04SupportNew builds, enhancements, takeovers and ongoing maintenance.
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Frequently asked questions
Why not just rewrite the component?
Rewrites often move the problem instead of fixing it.
How long does investigation take?
Usually hours, and it saves days of wasted work.
Can you investigate for us?
Yes — start with a store health check.
SA
Reviewed by Saeed Ak · Co-founder & CTO25 years engineering high-traffic ecommerce, cloud and security platforms. Written by the VISIBI Engineering team.Meet the team →
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