Performance
· 23 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
983 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.01 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
1.26 s
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.000
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
2.41 s
Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.
9.30 s
Page Load Progression
FPage Weight BudgetAction4.4 MB transferred, 148 requestsFIX
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
Source: web.dev
Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.
CSS bundle is large — purge unused styles (PurgeCSS, Tailwind JIT) to reduce CSS payload.
Source: web.dev
Subset fonts to include only used characters, or switch to system font stacks.
Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).
Source: web.dev font loading
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.
Source: web.dev
DThird-Party ImpactAction97% third-party, 0 ms blockingFIX
FJS Execution CostAction7231ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://github.githubassets.com/assets/chunk-39118-635712f2ef75199c.js | 4111ms | 113ms | 1ms | 3rd |
| https://github.githubassets.com/assets/react-lib-1353f2cef82bcdc0.js | 825ms | 622ms | 18ms | 3rd |
| https://github.com/ | 703ms | 6ms | 0ms | 1st |
| https://github.githubassets.com/assets/46752-7bd8967216f7ea42.js | 633ms | 35ms | 2ms | 3rd |
| Unattributable | 352ms | 37ms | 0ms | 3rd |
| https://github.githubassets.com/assets/landing-pages-29d9816a92404e81.js | 240ms | 168ms | 68ms | 3rd |
| https://github.githubassets.com/assets/behaviors-d9f0cee1f9e3eb0f.js | 222ms | 78ms | 13ms | 3rd |
| https://github.githubassets.com/assets/81058-fc9ccbdd06141af8.js | 145ms | 85ms | 1ms | 3rd |
FJS BundlesAction94 scripts, 789 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://github.githubassets.com/assets/landing-pages-29d9816a92404e81.js | 438 KB | 409 KB (93%) | ✓ | 3rd |
| https://github.githubassets.com/assets/primer-react-0eccd57ee759dfd8.js | 123 KB | 67 KB (55%) | ✓ | 3rd |
| https://github.githubassets.com/assets/react-lib-1353f2cef82bcdc0.js | 88 KB | 51 KB (59%) | ✓ | 3rd |
| https://github.githubassets.com/assets/48761-e0d707ef4ac523be.js | 114 KB | 48 KB (42%) | ✓ | 3rd |
| https://github.githubassets.com/assets/react-core-b2929a643e0ecc05.js | 66 KB | 46 KB (70%) | ✓ | 3rd |
| https://github.githubassets.com/assets/behaviors-d9f0cee1f9e3eb0f.js | 54 KB | 44 KB (81%) | ✓ | 3rd |
| https://github.githubassets.com/assets/37826-36074ccbdf2fd58c.js | 59 KB | 43 KB (74%) | ✓ | 3rd |
| https://github.githubassets.com/assets/70641-df7d286b6e757eb5.js | 102 KB | 33 KB (32%) | ✓ | 3rd |
| https://github.githubassets.com/assets/63050-9f22093e0909629c.js | 28 KB | 24 KB (88%) | ✓ | 3rd |
| https://github.githubassets.com/assets/67466-79abcbf599986a00.js | 31 KB | 23 KB (77%) | ✓ | 3rd |
Consider code splitting or tree shaking to reduce unused code.
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.
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.
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.
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.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
FPage Weight InventoryAction148 resources · 4.4 MB · 789 KB savings availableFIX
~788.6 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 148 resources | 4.4 MiB | ||||||
CImage OptimizationAction18 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
BHTTP/3 (QUIC)HTTP/3 not advertisedREVIEW
CCompression AlgorithmActionMain response served uncompressedREVIEW
BServer-Timing ObservabilityNo Server-Timing header foundREVIEW
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
BHTTP Cachingmax-age=0, private, must-revalidateREVIEW
max-age=0, private, must-revalidate
| Directive | Value | Meaning |
|---|---|---|
| max-age | 0 | Cache for 0 seconds |
| private | — | Only browser cache, not CDN/proxy |
| must-revalidate | — | Must recheck with server after expiry |
A+Text CompressionAll text resources are compressedPASS
A+Font Loading2 fonts (251 KB)PASS
Web fonts
2
251 KB total
Render-blocking
0
of 2
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
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)
Fixing the unchecked items could save ~107 KB and ~214 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+LCP Image PreloadLCP preload audit not availablePASS
A+Main HTML Cache-ControlMain HTML max-age=0 (≤ 5min) is appropriatePASS
A+Server Response Intelligence2 server-response signal(s) detectedPASS
Network Waterfall148 requests over 8179msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
github.githubassets.com github.githubassets.com | Other | 4111ms | 10 KB | — | $55/mo | Costly |
github.githubassets.com github.githubassets.com | Other | 825ms | 88 KB | 59% | $11/mo | Costly |
github.githubassets.com github.githubassets.com | Other | 633ms | 26 KB | — | $8/mo | Costly |
Unattributable Unattributable | Other | 352ms | 0 KB | — | $5/mo | Costly |
github.githubassets.com github.githubassets.com | Other | 240ms | 438 KB | 93% | $3/mo | Costly |
github.githubassets.com github.githubassets.com | Other | 222ms | 54 KB | 81% | $3/mo | Costly |
github.githubassets.com github.githubassets.com | Other | 145ms | 9 KB | — | $2/mo | Optional |
These scripts may cost more than they're worth
- github.githubassets.com adds 4111ms and costs ~$55/month
- github.githubassets.com adds 825ms and costs ~$11/month
- github.githubassets.com adds 633ms and costs ~$8/month
- Unattributable adds 352ms and costs ~$5/month
- github.githubassets.com adds 240ms and costs ~$3/month
- github.githubassets.com adds 222ms and costs ~$3/month
90% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.
Learn more ▾ ▴
Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.
Source: web.dev
github.githubassets.com takes 4111ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
github.githubassets.com takes 825ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
59% of github.githubassets.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
github.githubassets.com takes 633ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Unattributable takes 352ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
github.githubassets.com takes 240ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
93% of github.githubassets.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
github.githubassets.com takes 222ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
81% of github.githubassets.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
Real-User Performance (CrUX)Field metrics from the Chrome User Experience ReportINFO
Chrome User Experience (CrUX)
Real-user metrics from the Chrome UX Report (2026-04-11 — 2026-05-08)
LCP (p75)
2311 ms
78% good
INP (p75)
75 ms
92% good
CLS (p75)
0.080
84% good
FCP (p75)
1516 ms
TTFB (p75)
1112 ms
Image Optimization24 images, 101 KB total, 93 KB wastedINFO
Image Optimization Audit
Total Images
24
Total Size
101 KB
Oversized
3
Wasted
93 KB