https://poechallenges.cc
Performance
· 20 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.SCORE
93
GRADE
A
FIX
0
REVIEW
5
PASS
14
INFO
1
Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
83
92
100
100
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
454 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
951 ms
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
38 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.314
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
547 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.
953 ms
Page Load Progression
375 ms
750 ms 1.1 s 1.5 s 1.9 s 2.2 s 2.6 s 3.0 sChecks
2014 PASS 5 REVIEW
BJS Execution Cost526ms total JS executionREVIEW
JS Execution Cost
526ms total JS execution
526ms total JS execution
Warning::
https://poechallenges.cc/_next/static/chunks/12x_t...: 299ms CPU time
Info::
https://poechallenges.cc/: 165ms CPU time
Info::
Unattributable: 61ms CPU time
Main Thread Breakdown
Script Evaluation 49% Style & Layout 20% Other 16% Rendering 7% Script Parsing & Compilation 4% Garbage Collection 3%
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://poechallenges.cc/_next/static/chunks/12x_tm5bu80z2.js | 299ms | 265ms | 5ms | 1st |
| https://poechallenges.cc/ | 165ms | 1ms | 6ms | 1st |
| Unattributable | 61ms | 2ms | 0ms | 1st |
BJS Bundles6 scripts, 55 KB unusedREVIEW
JS Bundles
6 scripts, 55 KB unused
6 scripts, 55 KB unused
Warning::
https://poechallenges.cc/_next/static/chunks/14nk-...: 30 KB unused (61%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://poechallenges.cc/_next/static/chunks/12x_t...: 25 KB unused (36%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 55 KB
55 KB unused JavaScript
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://poechallenges.cc/_next/static/chunks/14nk-k_8h9ywg.js | 50 KB | 30 KB (61%) | ✓ | 1st |
| https://poechallenges.cc/_next/static/chunks/12x_tm5bu80z2.js | 70 KB | 25 KB (36%) | ✓ | 1st |
| https://poechallenges.cc/_next/static/chunks/073m0nq8aby5v.js | 7 KB | — | ✓ | 1st |
| https://poechallenges.cc/_next/static/chunks/turbopack-10e-4pr1lpam5.js | 5 KB | — | ✓ | 1st |
| https://poechallenges.cc/_next/static/chunks/00ck~hdkoj11u.js | 14 KB | — | ✓ | 1st |
| https://poechallenges.cc/_next/static/chunks/09kzygh-9mhpc.js | 50 KB | — | ✓ | 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
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
BMain HTML Cache-ControlCache-Control present but without max-ageREVIEW
Main HTML Cache-Control
Cache-Control present but without max-age
Cache-Control present but without max-age
Info::
Main HTML Cache-Control has no max-age: s-maxage=31536000
Got: s-maxage=31536000
BServer-Timing ObservabilityNo Server-Timing header foundREVIEW
Server-Timing Observability
No Server-Timing header found
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.
BHTTP Cachings-maxage=31536000REVIEW
HTTP Caching
s-maxage=31536000
s-maxage=31536000
Info::
Cache-Control header is set
Got: s-maxage=31536000
Info::
CDN TTL: 52 weeks (s-maxage=31536000)
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control
s-maxage=31536000
| Directive | Value | Meaning |
|---|---|---|
| s-maxage | 31536000 | CDN caches for 52 weeks |
A+Page Weight Budget363 KB transferred, 24 requestsPASS
Page Weight Budget
363 KB transferred, 24 requests
363 KB transferred, 24 requests
Info::
Page weighs 1.1 MB (363 KB transferred)
Info::
24 HTTP requests
Info::
Estimated 0.07 g CO2 per page load
363 KB transferred
24 requests
0.07 g CO2 per page load
JavaScript 196.3 KiB 54%
Fonts 74.4 KiB 21%
HTML 44.3 KiB 12%
Other 36.6 KiB 10%
CSS 10.1 KiB 3%
Other 1.2 KiB 0%
Images 0 B 0%
0 2.4 MB 4.9 MB
Under budget
A+Third-Party ImpactNo third-party resourcesPASS
Third-Party Impact
No third-party resources
No third-party resources
Info::
No third-party resources detected
No third-party resources detected — all resources are first-party.
A+Text CompressionAll text resources are compressedPASS
Text Compression
All text resources are compressed
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+Image Optimization3 images, 0 KB saveablePASS
Image Optimization
3 images, 0 KB saveable
3 images, 0 KB saveable
Info::
All images are well-optimized
3 images 0 KB
0 oversized -0 KB
0 legacy format
0 missing dimensions CLS risk
A+Font Loading2 fonts (74 KB)PASS
Font Loading
2 fonts (74 KB)
2 fonts (74 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
2
74 KB total
Render-blocking
0
of 2
Dominant font-display
swap
Most common across fonts
Font loading timeline
Transfer FOIT (block) FOUT (swap)
83afe278b6a6bb3c-s.p.0q... woff2 swap
Size 48 KB
Load time 53 ms
Start 121 ms
Risk FOUT — text flashes from fallback to web font
cc014fcb166cf364-s.p.0r... woff2 swap
Size 26 KB
Load time 33 ms
Start 122 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 CachingAll resources properly cachedPASS
Resource Caching
All resources properly cached
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+Critical Rendering PathNo render-blocking resourcesPASS
Critical Rendering Path
No render-blocking resources
No render-blocking resources
Info::
No render-blocking resources detected
A+Resource HintsNo optimization neededPASS
Resource Hints
No optimization needed
No optimization needed
Info::
No resource hint issues
A+HTTP/3 (QUIC)HTTP/3 advertised via Alt-SvcPASS
HTTP/3 (QUIC)
HTTP/3 advertised via Alt-Svc
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+Compression AlgorithmMain response uses brotliPASS
Compression Algorithm
Main response uses brotli
Main 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 PreloadLCP preload audit not availablePASS
LCP Image Preload
LCP preload audit not available
LCP preload audit not available
Info::
LCP image preload audit not available for this scan
A+Server Response Intelligence2 server-response signal(s) detectedPASS
Server Response Intelligence
2 server-response signal(s) detected
2 server-response signal(s) detected
Info::
`Vary` header declared: rsc, next-router-state-tree, next-router-prefetch, next-router-segment-prefetch,...
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 Inventory24 resources · 363 KB · 55 KB savings availablePASS
Page Weight Inventory
24 resources · 363 KB · 55 KB savings available
24 resources · 363 KB · 55 KB savings available
Info::
Within 1MB page-weight target
Got: 363 KB
Info::
~55 KB of savings available
Info::
3 third-party resources (0% of weight)
24 resources · 362.9 KiB · 3 third-party Within 1MB page-weight target
JavaScript 54% · 196.3 KiB
Font 21% · 74.4 KiB
Document 12% · 44.3 KiB
Other 10% · 36.6 KiB
CSS 3% · 10.1 KiB
Image 0% · 1.2 KiB
~55.0 KiB of savings available
Remove unused JavaScript: 55.0 KiB
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 24 resources | 362.9 KiB | ||||||
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
Whether the site is served from green-energy infrastructure
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Network Waterfall24 requests over 586msINFO
Network Waterfall
24 requests over 586ms
HTML JavaScript CSS Images Fonts XHR/Fetch Other
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.