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https://esl-go.com

Performance

· 22 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
93
GRADE
A
FIX
0
REVIEW
3
PASS
16
INFO
3

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
96
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
90
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
100
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
92
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

790 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

1.26 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

0 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.038

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

790 ms

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

1.26 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
22
16 PASS 3 REVIEW
B
JS Bundles
1 scripts, 91 KB unused
REVIEW
1 scripts, 91 KB unused
Warning::
https://esl-go.com/assets/index-DfSHavb5.js: 91 KB unused (55%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://esl-go.com/assets/index-DfSHavb5.js: unminified — 29 KB could be saved
Info::
Total unused JavaScript: 91 KB
91 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://esl-go.com/assets/index-DfSHavb5.js166 KB91 KB (55%)✗1st

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

B
Server-Timing Observability
No Server-Timing header found
REVIEW
No Server-Timing header found
Info::
No Server-Timing header found
Server-Timing exposes backend timing breakdowns to browser DevTools (e.g., `db: 45ms; render: 120ms; cache: 2ms`). Useful for diagnosing slow pages without backend log access. Most modern frameworks (Next.js, Cloudflare Workers, Fastly) emit it automatically; absence on a managed platform usually means telemetry headers are stripped at the edge.
B
HTTP Caching
public, max-age=0, must-revalidate
REVIEW
public, max-age=0, must-revalidate
Info::
Cache-Control header is set
Got: public, max-age=0, must-revalidate
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

public, max-age=0, must-revalidate

DirectiveValueMeaning
public—Any cache may store this response
max-age0Cache for 0 seconds
must-revalidate—Must recheck with server after expiry
A+
Page Weight Budget
668 KB transferred, 13 requests
PASS
668 KB transferred, 13 requests
Info::
Page weighs 1.5 MB (668 KB transferred)
Info::
13 HTTP requests
Info::
Estimated 0.14 g CO2 per page load
668 KB / 2.4 MB budget
668 KB transferred
13 requests
0.14 g CO2 per page load
Images 462.1 KiB 69%
JavaScript 166.2 KiB 25%
Fonts 26.7 KiB 4%
CSS 10.3 KiB 2%
Other 1.4 KiB 0%
HTML 1.2 KiB 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Under budget
A
Third-Party Impact
34% third-party, 0 ms blocking
PASS
34% third-party, 0 ms blocking
Info::
Third-party code accounts for 34% of page weight (225.5 KiB of 667.9 KiB)
Info::
Third-party blocking time is low (0 ms)
66%
34%
First-party Third-party
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
Image Optimization
6 images, 0 KB saveable
PASS
6 images, 0 KB saveable
Info::
All images are well-optimized
6 images 462 KB
0 oversized -0 KB
1 legacy format
0 missing dimensions CLS risk
A+
JS Execution Cost
234ms total JS execution
PASS
234ms total JS execution
Info::
https://esl-go.com/: 86ms CPU time
Info::
Unattributable: 76ms CPU time
Info::
https://esl-go.com/assets/index-DfSHavb5.js: 71ms CPU time

Main Thread Breakdown

Other 39% Style & Layout 29% Script Evaluation 27% Rendering 3%
ScriptTotalScriptingParse/CompileParty
https://esl-go.com/86ms1ms0ms1st
Unattributable76ms1ms0ms1st
https://esl-go.com/assets/index-DfSHavb5.js71ms62ms1ms1st
A+
Font Loading
1 fonts (27 KB)
PASS
1 fonts (27 KB)
Info::
1 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

1

27 KB total

Render-blocking

0

of 1

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s FCP 790 ms LCP 1.3 shttps://fonts.gstatic.com/s/plusjakartasans/v12/LDIoaomQNQcsA88c7O9yZ4KMCoOg4Ko20yygg_vb.woff2LDIoaomQNQcsA88c7O9yZ4K... https://fonts.gstatic.com/s/plusjakartasans/v12/LDIoaomQNQcsA88c7O9yZ4KMCoOg4Ko20yygg_vb.woff2 — 26.7 KiB — 25 ms — font-display: swap
LDIoaomQNQcsA88c7O9yZ4K... woff2 swap
Size 27 KB
Load time 25 ms
Start 284 ms
Risk FOUT — text flashes from fallback to web font
Optimization checklist
  • Preload critical fonts (priority=high)
  • Use woff2 format for all fonts
  • Set font-display to swap, optional, or fallback
  • Subset large fonts (≤100 KB each)
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
A+
HTTP/3 (QUIC)
HTTP/3 advertised via Alt-Svc
PASS
HTTP/3 advertised via Alt-Svc
Info::
HTTP/3 (QUIC) is supported
First-load mobile users on cellular networks see meaningful latency improvements with HTTP/3. The QUIC transport collapses TLS + TCP handshakes into one and recovers faster from packet loss.
A+
Document Compression
Document response uses brotli
PASS
Document response uses brotli
Info::
Main HTML response uses brotli (Content-Encoding: br)
Brotli is the best text-compression algorithm for general use, ~20% smaller than gzip on average (40% on smaller files). Modern browsers all support it.
A+
LCP Image Preload
LCP preload audit not available
PASS
LCP preload audit not available
Info::
LCP image preload audit not available for this scan
A+
Main HTML Cache-Control
Main HTML max-age=0 (≤ 5min) is appropriate
PASS
Main HTML max-age=0 (≤ 5min) is appropriate
Info::
Main HTML max-age=0 (≤ 5min) is appropriate
Got: public, max-age=0, must-revalidate
A+
Server Response Intelligence
2 server-response signal(s) detected
PASS
2 server-response signal(s) detected
Info::
`Vary` header declared: accept-encoding
The page declares a `Vary` header, telling downstream caches which request headers the response varies on. Critical for content-negotiated responses (compression, language, cookies, device class).
Info::
No `ETag` or `Last-Modified` -- conditional GET not supported
Without either header, browsers can't issue conditional GETs and refresh always re-downloads the full response body even when nothing changed. Add `ETag: "<hash>"` (or `Last-Modified: <date>`) on cacheable responses; the server returns 304 Not Modified when the client's cached copy is still valid, saving bandwidth.
A+
Page Weight Inventory
13 resources · 668 KB · 91 KB savings available
PASS
13 resources · 668 KB · 91 KB savings available
Info::
Within 1MB page-weight target
Got: 668 KB
Info::
~91 KB of savings available
Info::
8 third-party resources (34% of weight)
Info::
1 resources over 200KB
13 resources · 667.9 KiB · 8 third-party Within 1MB page-weight target
Image 69% · 462.1 KiB
JavaScript 25% · 166.2 KiB
Font 4% · 26.7 KiB
CSS 2% · 10.3 KiB
Other 0% · 1.4 KiB
Document 0% · 1.2 KiB

~90.7 KiB of savings available

Remove unused JavaScript: 90.7 KiB
A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

Asset Compression
No text asset hosts to measure
INFO
No text asset hosts to measure
Info::
No third-party or subdomain host served enough text assets to measure
Asset compression is measured per host, from one HEAD request against a sampled resource. Pages that serve all their JS and CSS from the document's own origin are covered by the document compression check instead.
Network Waterfall
13 requests over 555ms
INFO
0 ms 500 ms 1.0 s FCP 790 ms LCP 1.3 shttps://esl-go.com// https://esl-go.com/ — 200 — 1.2 KiB — 80 ms — h3https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=Plus+Jakarta+Sans:wght@500;600;700;800&display=swapfonts.googleapis.com/css2?family=In... https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=Plus+Jakarta+Sans:wght@500;600;700;800&display=swap — 200 — 1.4 KiB — 66 ms — h2https://esl-go.com/assets/index-DfSHavb5.js/assets/index-DfSHavb5.js https://esl-go.com/assets/index-DfSHavb5.js — 200 — 166.2 KiB — 72 ms — h3https://esl-go.com/assets/index-wDnpTs0m.css/assets/index-wDnpTs0m.css https://esl-go.com/assets/index-wDnpTs0m.css — 200 — 8.9 KiB — 38 ms — h3https://esl-go.com/logo.png/logo.png https://esl-go.com/logo.png — 200 — 266.1 KiB — 50 ms — h3https://images.unsplash.com/photo-1456513080510-7bf3a84b82f8?w=800&auto=format&fit=crop&q=80images.unsplash.com/photo-145651308... https://images.unsplash.com/photo-1456513080510-7bf3a84b82f8?w=800&auto=format&fit=crop&q=80 — 200 — 25.6 KiB — 12 ms — h2https://images.unsplash.com/photo-1529156069898-49953e39b3ac?w=800&auto=format&fit=crop&q=80images.unsplash.com/photo-152915606... https://images.unsplash.com/photo-1529156069898-49953e39b3ac?w=800&auto=format&fit=crop&q=80 — 200 — 38.4 KiB — 13 ms — h2https://images.unsplash.com/photo-1517486808906-6ca8b3f04846?w=800&auto=format&fit=crop&q=80images.unsplash.com/photo-151748680... https://images.unsplash.com/photo-1517486808906-6ca8b3f04846?w=800&auto=format&fit=crop&q=80 — 200 — 72.1 KiB — 15 ms — h2https://images.unsplash.com/photo-1522202176988-66273c2fd55f?w=800&auto=format&fit=crop&q=80images.unsplash.com/photo-152220217... https://images.unsplash.com/photo-1522202176988-66273c2fd55f?w=800&auto=format&fit=crop&q=80 — 200 — 43.8 KiB — 15 ms — h2https://fonts.gstatic.com/s/plusjakartasans/v12/LDIoaomQNQcsA88c7O9yZ4KMCoOg4Ko20yygg_vb.woff2fonts.gstatic.com/s/plusjakartasans... https://fonts.gstatic.com/s/plusjakartasans/v12/LDIoaomQNQcsA88c7O9yZ4KMCoOg4Ko20yygg_vb.woff2 — 200 — 26.7 KiB — 25 ms — h3https://media.esl-go.com/metadata/catalog.json?_t=1789950767437media.esl-go.com/metadata/catalog.j... https://media.esl-go.com/metadata/catalog.json?_t=1789950767437 — 200 — 1.4 KiB — 249 ms — h2https://esl-go.com/logo.png/logo.png https://esl-go.com/logo.png — 200 — 0 B — 3 ms — h3https://images.unsplash.com/photo-1505740420928-5e560c06d30e?w=800&auto=format&fit=crop&q=80images.unsplash.com/photo-150574042... https://images.unsplash.com/photo-1505740420928-5e560c06d30e?w=800&auto=format&fit=crop&q=80 — 200 — 16.1 KiB — 3 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Image Optimization
8 images, 742 KB total, 429 KB wasted
INFO

Image Optimization Audit

Total Images

8

Total Size

742 KB

Oversized

6

Wasted

429 KB

8 missing dimensions 5 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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