u/Dangerous_Bug4440

Our React monolith hit 280,000 lines. PRs sat for days. Deploys needed 3-team sign-offs. Here's what actually worked.

I've been through two micro-frontend migrations at scale and made some expensive mistakes along the way. Wrote up everything I wish someone had told me before we started — the three integration strategies (and when NOT to use each), the 5 problems nobody warns you about (dependency hell, shared state traps, design system drift), and honestly, when you probably shouldn't bother with MFEs at all.

If your team is dealing with merge conflict hell or slow deploys, this might be worth a read:

https://dev.to/shudhanshuraj/micro-frontend-architecture-how-to-split-a-monolith-without-losing-your-mind-217e

Happy to answer questions in the comments — I've spent a lot of time in the trenches on this.

I spent 6 months trying to improve Core Web Vitals on a real production app.

At first, we were obsessed with Lighthouse scores. Everything looked green locally (92–98), but users on mid-range Android devices still complained that the app felt slow.

That disconnect completely changed how I think about frontend performance.

A few things that actually moved the needle for us:

• Breaking long tasks with scheduler.yield()
• Prioritizing INP instead of only LCP
• Deferring expensive React renders with useDeferredValue
• Finding hidden long tasks from third-party analytics scripts
• Fixing CLS with reserved layout space instead of hacks
• Treating CrUX data as the real scoreboard, not Lighthouse

One interaction on our listing page dropped from ~480ms INP to ~170ms after restructuring event handling.

I wrote a detailed breakdown of what worked, what didn’t, and the production mistakes we made along the way:

https://dev.to/shudhanshuraj/i-spent-six-months-chasing-core-web-vitals-heres-what-actually-moved-the-needle-2ofd

Would love feedback from engineers who’ve fought similar performance battles. What ended up being your biggest bottleneck? 🚀