How I Would Fix slow pages and weak Core Web Vitals in a React Native and Expo automation-heavy service business Using Launch Ready.

How I Would Fix slow pages and weak Core Web Vitals in a React Native and Expo automation-heavy service business Using Launch Ready

The symptom is usually obvious: the site feels fine on your laptop, but on mobile it crawls, buttons lag, pages jump around, and Google keeps flagging poor Core Web Vitals. In an automation-heavy service business, the most likely root cause is not "React Native" by itself, it is too much work happening at once: heavy JS bundles, expensive client-side rendering, unoptimized images, third-party scripts, and API calls that block the first useful paint.

If I were auditing this first, I would inspect the homepage and top conversion pages on a throttled mobile profile before touching code. I want to see what delays LCP, what causes CLS, and whether INP is being hurt by too many scripts, too much state churn, or slow backend responses.

Triage in the First Hour

1. Open the main landing page and the top booking or lead form on a real mobile device. 2. Run Lighthouse in Chrome with mobile throttling and save the report. 3. Check Core Web Vitals in Search Console or your analytics tool for field data, not just lab data. 4. Inspect Expo build output for bundle size warnings and unused dependencies. 5. Review network waterfalls for large images, fonts, analytics tags, chat widgets, and CRM scripts. 6. Check whether API calls are firing before above-the-fold content is visible. 7. Review Cloudflare settings for caching rules, compression, image optimization, and redirect chains. 8. Inspect logs for slow endpoints, timeouts, repeated retries, or failed asset loads. 9. Confirm whether environment variables or secrets are forcing extra runtime calls or blocking startup. 10. Check if any automation flows are running on page load instead of after user intent.

A quick diagnostic command I would run during triage:

npx expo export --platform web
npx source-map-explorer dist/**/*.js

That tells me whether the web bundle is bloated enough to explain slow first load. If the main chunk is huge or full of unused packages, that becomes a priority before any UI polish.

Root Causes

| Likely cause | What it looks like | How I confirm it | |---|---|---| | Oversized JS bundle | Slow first render, delayed interactivity | Bundle analysis shows large vendor chunks or duplicate libraries | | Heavy third-party scripts | Good local dev speed but bad production performance | Network waterfall shows analytics, chat, pixels, or CRM tools blocking main thread | | Unoptimized images and media | Poor LCP and layout shifts | Lighthouse flags oversized images or missing dimensions | | Client-side fetching too early | Blank hero area while data loads | Waterfall shows API calls before content renders | | Weak caching and CDN setup | Repeated downloads on every visit | Response headers show low cache hit rate or no edge caching | | Too much state work in React Native web | Janky scrolling and poor INP | Profiler shows frequent rerenders from shared state or expensive components |

For an automation-heavy service business, I also watch for one specific pattern: founders wiring forms directly into several tools at once. That creates slow page loads because every script wants to initialize immediately, even when the user has not clicked anything yet.

The Fix Plan

First I would separate "marketing speed" from "automation logic." The landing page should sell the service fast; the automations should run after conversion events like form submit, booking confirmation, or email capture.

Second I would reduce what ships to the browser. In React Native with Expo web support, that means removing unused packages, splitting non-critical screens out of the initial route path, lazy-loading heavy components, and replacing always-on widgets with user-triggered loading.

Third I would clean up media delivery. Hero images should be compressed properly with fixed dimensions to stop layout shift. If there are videos or animated backgrounds on the homepage, I would remove them unless they directly improve conversion.

Fourth I would move expensive work off the critical path. Anything related to CRM syncs, email enrichment, webhook fan-out, Slack alerts, scoring logic, or follow-up automations should happen server-side after submission through queues or background jobs.

Fifth I would harden Cloudflare and caching settings. Static assets should be cached aggressively at the edge where safe to do so. Redirect chains should be flattened so domain changes do not create extra round trips.

Sixth I would review security while fixing performance. For this kind of service business launch stack - domain setup, email deliverability, SSL, secrets - weak security often creates hidden performance problems too. Broken SPF/DKIM/DMARC can delay email workflows; exposed secrets can trigger abuse; missing rate limits can let bots hammer forms and degrade uptime.

My preferred sequence is:

1. Fix largest bundle wins first. 2. Remove render-blocking third parties next. 3. Optimize hero media and fonts. 4. Push automation off-page into backend jobs. 5. Tune caching and Cloudflare rules. 6. Re-test Core Web Vitals before any redesign work.

That order avoids a common mistake: redesigning screens when the real issue is infrastructure drag.

Regression Tests Before Redeploy

I would not ship until these checks pass:

• Lighthouse mobile score is at least 85 overall.
• LCP is under 2.5 seconds on a throttled mobile profile.
• CLS is under 0.1.
• INP stays under 200 ms for key interactions like menu open and form submit.
• Initial JS payload drops by at least 25 percent from baseline if bundle bloat was confirmed.
• No critical console errors appear on load.
• Forms still submit correctly with validation enabled.
• Booking flow works end to end in production-like conditions.
• Email deliverability records resolve correctly for SPF/DKIM/DMARC.
• Cloudflare caching does not break authenticated routes or dynamic pages.
• Secrets are not exposed in client bundles or logs.

I also want one manual exploratory pass on iPhone-sized viewports and one pass on a slower Android device if possible. Performance bugs often hide behind desktop testing because desktop hardware masks poor rendering decisions.

Prevention

I would put guardrails in place so this does not come back two weeks later.

• Add performance budgets for JS size and image weight in CI.
• Require Lighthouse checks before release on key landing pages.
• Review new third-party scripts before they go live.
• Keep sensitive automations server-side only unless there is a clear reason not to.
• Use least privilege for API keys and environment variables.
• Log failed form submissions without storing personal data unnecessarily.
• Set uptime monitoring on homepage load time plus booking funnel availability.
• Add rate limits and bot protection to public forms.

From a cyber security lens this matters as much as speed does. A slow site that also leaks secrets or accepts unlimited bot traffic will waste ad spend twice: once through lost conversions and again through support load and incident cleanup.

For UX guardrails, keep the homepage simple:

• One clear value proposition above the fold.
• One primary CTA.
• Minimal animation on first view.
• Fast-loading trust signals instead of dense copy blocks.

If you need more proof that something helps conversion than theory alone gives you use small A/B tests after performance fixes land rather than mixing multiple changes at once.

When to Use Launch Ready

Use Launch Ready when you need this fixed fast without turning it into a month-long rebuild. The sprint fits best if you already have a working React Native or Expo product but your pages are hurting conversion because they load slowly or fail Core Web Vitals.

I would recommend it if:

• Your site is live but underperforming on mobile traffic.
• You are about to spend money on ads but do not trust your funnel yet.
• You have automation-heavy flows that need cleanup before scaling traffic.
• You need secure deployment without exposing customer data or breaking email deliverability.

What you should prepare before kickoff: 1. Access to domain registrar DNS hosting Cloudflare GitHub Expo hosting platform email provider analytics tool and error monitoring if available. 2. A list of top pages by revenue lead volume or booking intent. 3. Any recent deploys where performance dropped noticeably. 4. Current environment variable inventory without sharing raw secrets over insecure channels if avoidable. 5. Examples of broken flows including screenshots screen recordings or URLs.

If you bring me access plus a clear priority order I can usually tell within hours whether this is mostly frontend bloat backend latency bad caching or tag sprawl causing the slowdown.

References

1. Roadmap.sh Frontend Performance Best Practices - https://roadmap.sh/frontend-performance-best-practices 2. Roadmap.sh Cyber Security - https://roadmap.sh/cyber-security 3. Roadmap.sh QA - https://roadmap.sh/qa 4. Google Web.dev Core Web Vitals - https://web.dev/vitals/ 5. Expo Docs - https://docs.expo.dev/

---

Take the next step

If this is a problem in your product right now, here is what to do next:

• [Use the free Cyprian tools](/tools) - estimate cost, score app risk, check launch readiness, or pick the right service sprint.

• [Book a discovery call](/contact) - I will tell you honestly whether you need a sprint or if you can DIY the next step.

*Written by Cyprian Tinashe Aarons - senior full-stack and AI engineer helping founders rescue, launch, automate, and scale AI-built products.*