The objective is simple: reduce the time from click to value. In 2025 that means: improve Core Web Vitals (LCP, INP, CLS), upgrade the network (HTTP/3, TLS 1.3), trim JavaScript, and cache smartly at the edge. Below are 25 concrete moves, with notes on deploying them on Unihost VPS and dedicated servers.
1) LCP under 2.5s
Push the hero element early, use fetchpriority=high, preload critical assets, and minimize blocking CSS.
2) INP replaces FID
Break up handlers, offload heavy work to Web Workers, cut sync JS, use passive listeners.
3) Tame CLS
Reserve space via width/height/aspect‑ratio, avoid DOM shifts above content, use font‑display: swap.
4) HTTP/3 + TLS 1.3
Enable QUIC, OCSP stapling, consider 0‑RTT only for idempotent calls; keep modern cipher suites.
5) CDN & geo
Serve static assets from a CDN with edge caching and image transforms.
6) Images
AVIF/WebP, srcset/sizes, loading=lazy, decoding=async.
7) Critical CSS
Inline critical; preload the rest as style then swap to stylesheet.
8) Less JS
Tree‑shake, code‑split, dynamic import; drop unnecessary polyfills.
9) Defer/async
Defer non‑critical scripts; prioritize core journeys first.
10) Islands architecture
Prefer SSR/SSG/ISR with partial hydration; ship less JS to the client.
11) Edge rendering
Move templating to the edge; cache HTML by geo/lang; use stale‑while‑revalidate.
12) Cache headers
Static: long max‑age + immutable; HTML: short TTL + ETag/Last‑Modified.
13) Brotli
Pre‑compress CSS/JS/HTML and enable Brotli on front‑ends.
14) Fonts
Use subsets and WOFF2, preconnect to font CDNs, font‑display: swap/optional.
15) Network priorities
Preconnect, dns‑prefetch, preload wisely – and avoid unnecessary connections.
16) 103 Early Hints
Send early hints for critical CSS/fonts/hero media.
17) Service Worker
Cache the shell and static assets; prefer stale‑while‑revalidate.
18) HTML streaming
Stream responses and use server components to reduce client JS.
19) Database + cache
Index hot queries, avoid N+1, add Redis/KeyDB, reduce payloads, pool connections.
20) API batching
Aggregate requests and keep connections alive with compression.
21) Third‑party scripts
Tag Manager hygiene, consent‑based loading, timeouts and caps.
22) Mobile networks
Reduce request count, enable client hints, use responsive images and light animations.
23) RUM & synthetics
Measure real users and synthetic checks across regions; create SLOs and alerts.
24) Perf gates in CI/CD
Block merges when Lighthouse/CWV budgets regress.
25) Plan & governance
Define priorities, owners and SLAs; report gains with numbers.
Unihost rollout checklist
CWV audit → CDN/HTTP/3 → images → critical CSS → JS refactor → edge cache/SWR → RUM+synthetics → CI/CD performance gates. Unihost engineers can size servers, enable HTTP/3 and CDN, and set up monitoring.
FAQ
Do we need everything at once? – No, start with the top LCP/INP wins. Can we skip the CDN? – Not if you serve global traffic. Why does less JS help? – Fewer main‑thread blocks and smaller bundles reduce latency.
Conclusion
Speed is a continuous practice. Prioritize CWV, network and caching, and automate quality control. Unihost provides the infrastructure: servers, HTTP/3, CDN, security and observability.
Measurement methodology and budgets
- Collect RUM for LCP/INP/CLS by country and device; run synthetic checks from 3–5 regions.
- Set performance budgets: HTML 50–80 KB, critical CSS ≤ 100 KB, initial JS ≤ 170–200 KB.
- Track before/after tables with LCP, INP, bundle sizes, TTFB and edge cache hit‑ratio.
Use‑case patterns
- Content sites: SSG/ISR, CDN, aggressive static caching, AVIF/WebP, minimal client JS.
- E‑commerce: server components, edge caching for category/search, cart API batching, DB tuning and Redis.
- SaaS: islands, workers for heavy compute, CI perf gates and sampled RUM.
Anti‑patterns to avoid
Shipping entire CSS/JS frameworks, dozens of third‑party tags, multi‑MB PNG hero images, fonts without subsets, unnecessary polyfills and endless animations – all bloat the bundle and hurt INP and LCP.
30‑day action plan
- Week 1: audit CWV and enable HTTP/3/CDN; wire up RUM dashboards.
- Week 2: images/fonts, critical CSS, third‑party cleanup.
- Week 3: JS refactor and edge HTML caching.
- Week 4: DB/API tuning and CI gates; finalize report and QBR roadmap.
Who does what: product, dev and infra
Dev owns critical CSS, JS diet, third‑party hygiene, islands and progressive enhancement; Infra owns CDN, HTTP/3, edge cache, Brotli, Early Hints and geo. The product owner prioritizes a simple matrix: step → LCP/INP gain → effort → risk.
Diagnostics and tooling
Lighthouse, WebPageTest, Chrome DevTools (Coverage/Performance), framework profilers, Server‑Timing markers and RUM dashboards. In CI use Lighthouse CI with budgets and baseline comparison to stop regressions at PR time.
Nginx/CDN practical notes
Enable HTTP/3, Brotli and long‑lived cache headers for static assets in Nginx; keep short TTL + revalidation for HTML. On a CDN, cache HTML at the edge with SWR, use image transforms and publish a status page for incidents.
Images & fonts: detailed checklist
- Images: prefer AVIF/WebP, prepare 2–3 width breakpoints with srcset/sizes, cap DPR≤2 on mobile, lazy‑load offscreen media and use decoding=async. Make the LCP image a first‑class citizen via preload and fetchpriority=high. Enable transforms on your CDN.
- Fonts: remove unused variants, subset by language, ship WOFF2, preconnect to font CDNs, use font‑display: swap/optional and a system fallback in critical CSS. Beware oversized variable fonts; several WOFF2 files may still be smaller.
Business impact and metrics
After image and JS diet, many sites see −20–40% LCP and −15–25% INP. Run A/B comparisons with seasonality control, and translate savings (MB and ms) into revenue terms for stakeholders.
Performance policy and guardrails
Define budgets (HTML/CSS/JS), third‑party rules, image/font requirements and CLS/INP limits. Enforce via CI gates; hold monthly reviews to prune dead dependencies and regressions.
Edge caching and SWR in practice
For category/search pages, set short edge TTLs (5–60s) with stale‑while‑revalidate so visitors get instant pages while revalidation happens in the background. Vary HTML by language/geo/device, and mark variations explicitly with Vary headers.
SPAs and hydration
If moving away from SPA is not feasible, use partial hydration/islands, code splitting and lazy route/component loading, plus prerendering (SSG/ISR) for public pages. A Service Worker can cache the shell and API responses for repeat visits.
Analytics and third‑party discipline
Route all tags through a Tag Manager, load on consent, measure their impact on INP/LCP, set timeouts/retries, and block unsolicited popups or redirects. Apply the same scrutiny to ads, chat widgets, maps and media players.
Troubleshooting: when metrics spike
Check server queues, network capacity, edge cache hit‑ratio, cold regions and image sizes in feeds. Segment by device: older Androids often yield worse INP. In RUM, reduce noise via sampling and trim outliers in reporting (not alerts).
Ownership and cadence
Define an on‑call rotation and a performance owner; schedule regular dashboard reviews and a backlog of perf tasks. Attach a brief perf note to every release: what changed, budget impact, and next steps.
Final tip: annotate dashboards with release markers and change reasons. It speeds up root‑cause analysis and helps product track how performance translates into business outcomes.
How Unihost can help
We handle both infrastructure and practical optimization – from metrics audits to CDN rollout and CI/CD perf gates.
- CWV (LCP/INP/CLS), network and backend audit with a prioritized action plan and impact estimates.
- Migration to optimal VPS/dedicated tiers, clustering and load balancing.
- Nginx/HTTP/3, TLS 1.3, HSTS, WAF; SSL issuance and auto‑renewal.
- CDN and edge caching for HTML/static assets; image transforms (WebP/AVIF).
- Fonts/images optimization, critical CSS, third‑party hygiene and JS dieting.
- Observability: RUM & synthetics, Prometheus/Grafana, alerts and status pages.
- CI/CD: performance budgets and gates, automated before/after reports.
- 24/7 SLA support or one‑off “turn‑key” engagements.
Ping us – we’ll propose a plan, budget and expected LCP/INP gains for your target regions.