https://github.blog
Performance
· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.SCORE
83
GRADE
B
FIX
1
REVIEW
4
PASS
8
INFO
2
Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
86
89
100
92
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
340 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.59 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
8 ms
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.
362 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.
2.61 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 sChecks
158 PASS 4 REVIEW 1 FIX
FPage Weight BudgetAction3.4 MB transferred, 49 requestsFIX
Page Weight Budget
Action3.4 MB transferred, 49 requests
3.4 MB transferred, 49 requests
Warning::
Page weighs 4.9 MB (3.4 MB transferred)
Warning::
Images are 1.8 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 1.8 MB
Info::
Fonts are 1.3 MB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 1.3 MB
Info::
49 HTTP requests
Info::
Estimated 0.71 g CO2 per page load
3.4 MB transferred
49 requests
0.71 g CO2 per page load
Images 1.8 MiB 52%
Fonts 1.3 MiB 38%
JavaScript 203.8 KiB 6%
CSS 83.9 KiB 2%
HTML 37.6 KiB 1%
Other 6.8 KiB 0%
Other 469 B 0%
0 2.4 MB 4.9 MB
Over budget
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Why this matters
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
Source: web.dev
Subset fonts to include only used characters, or switch to system font stacks.
Why this matters
Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).
Source: web.dev font loading
BImage Optimization29 images, 0 KB saveableREVIEW
Image Optimization
29 images, 0 KB saveable
29 images, 0 KB saveable
Info::
All images are well-optimized
29 images 1.8 MB
0 oversized -0 KB
7 legacy format
0 missing dimensions CLS risk
BJS Bundles14 scripts, 90 KB unusedREVIEW
JS Bundles
14 scripts, 90 KB unused
14 scripts, 90 KB unused
Warning::
https://js.monitor.azure.com/scripts/c/ms.analytic...: 90 KB unused (88%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://js.monitor.azure.com/scripts/c/ms.analytic...: unminified — 38 KB could be saved
Info::
Total unused JavaScript: 90 KB
90 KB unused JavaScript
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://js.monitor.azure.com/scripts/c/ms.analytics-web-4.js | 103 KB | 90 KB (88%) | ✗ | 3rd |
| https://github.blog/wp-includes/js/dist/url.min.js?m=1774626885g | 4 KB | — | ✓ | 1st |
| https://ghcc.githubassets.com/ghcc.min.js | 18 KB | — | ✓ | 3rd |
| https://github.blog/wp-includes/js/dist/script-modules/interactivity/index.min.js?ver=66c613f68580994bb00a | 16 KB | — | ✓ | 1st |
| https://github.blog/_static/??/wp-content/plugins/gh-cookie-consent-and-tracking/dist/js/cookie-consent-and-tracking.js,/wp-includes/js/dist/hooks.min.js?m=1776795618j | 4 KB | — | ✓ | 1st |
| https://github.blog/wp-includes/js/dist/i18n.min.js?ver=c26c3dc7bed366793375 | 3 KB | — | ✓ | 1st |
| https://github.blog/wp-content/themes/github-2021/dist/blocks/category-filter/view-module.js?ver=c98e3bfa4bc2be7e7654 | 1 KB | — | ✓ | 1st |
| https://github.blog/wp-includes/js/dist/api-fetch.min.js?ver=3a4d9af2b423048b0dee | 3 KB | — | ✓ | 1st |
| https://github.blog/_static/??/wp-content/themes/github-2021/dist/js/site-script.js,/wp-content/plugins/page-links-to/dist/new-tab.js?m=1776795618j | 41 KB | — | ✓ | 1st |
| https://analytics.githubassets.com/v1.1.0/hydro-marketing.min.js?ver=6.9.4 | 4 KB | — | ✓ | 3rd |
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
CPage Weight InventoryAction49 resources · 3.4 MB · 90 KB savings availableREVIEW
Page Weight Inventory
Action49 resources · 3.4 MB · 90 KB savings available
49 resources · 3.4 MB · 90 KB savings available
Warning::
Page weight 2.4 MB over 1MB target
Got: 3.4 MB Expected: ≤ 1 MB
Info::
~90 KB of savings available
Info::
11 third-party resources (4% of weight)
Info::
3 resources over 200KB
49 resources · 3.4 MiB · 11 third-party 2.4 MiB over 1MB target
Image 52% · 1.8 MiB
Font 38% · 1.3 MiB
JavaScript 6% · 203.8 KiB
CSS 2% · 83.9 KiB
Document 1% · 37.6 KiB
Other 0% · 469 B
~89.6 KiB of savings available
Remove unused JavaScript: 89.6 KiB
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 49 resources | 3.4 MiB | ||||||
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
ActionWhether the site is served from green-energy infrastructure
Green Hosting
No green hosting detected
A+Third-Party Impact4% third-party, 0 ms blockingPASS
Third-Party Impact
4% third-party, 0 ms blocking
4% third-party, 0 ms blocking
Info::
Third-party code accounts for 4% of page weight (138.5 KiB of 3.4 MiB)
Info::
Third-party blocking time is low (0 ms)
96%
First-party Third-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+JS Execution Cost435ms total JS executionPASS
JS Execution Cost
435ms total JS execution
435ms total JS execution
Warning::
https://github.blog/: 288ms CPU time
Info::
Unattributable: 85ms CPU time
Info::
https://github.blog/_static/??/wp-content/themes/g...: 62ms CPU time
Info::
Third-party scripts: 85ms (20% of total)
Main Thread Breakdown
Style & Layout 40% Other 30% Script Evaluation 13% Rendering 8% Parse HTML & CSS 4% Script Parsing & Compilation 4%
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://github.blog/ | 288ms | 6ms | 1ms | 1st |
| Unattributable | 85ms | 10ms | 0ms | 3rd |
| https://github.blog/_static/??/wp-content/themes/github-2021/dist/js/site-script.js,/wp-content/plugins/page-links-to/dist/new-tab.js?m=1776795618j | 62ms | 22ms | 3ms | 1st |
A+Font Loading2 fonts (1337 KB)PASS
Font Loading
2 fonts (1337 KB)
2 fonts (1337 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
2
1337 KB total
Render-blocking
0
of 2
Dominant font-display
swap
Most common across fonts
Font loading timeline
Transfer FOIT (block) FOUT (swap)
mona-sans.woff2 woff2 swap
Size 134 KB
Load time 33 ms
Start 22 ms
Risk FOUT — text flashes from fallback to web font
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
MonaspaceNeon-Regular.w... woff2 swap
Size 1203 KB
Load time 75 ms
Start 23 ms
Risk FOUT — text flashes from fallback to web font
- 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 ~669 KB and ~1338 ms
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
AHTTP Cachingmax-age=300 (5 minutes)PASS
HTTP Caching
max-age=300 (5 minutes)
max-age=300 (5 minutes)
Info::
Cache-Control header is set
Got: max-age=300, must-revalidate
Info::
Effective TTL: 5 minutes (max-age=300)
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control
max-age=300, must-revalidate
| Directive | Value | Meaning |
|---|---|---|
| max-age | 300 | Cache for 5 minutes |
| must-revalidate | — | Must recheck with server after expiry |
Effective TTL: 300 seconds
Network Waterfall49 requests over 751msINFO
Network Waterfall
49 requests over 751ms
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
20% of JavaScript execution is third-party
First-party Third-party 85ms · 0KB · $0/mo
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 85ms | 0 KB | — | $0/mo | Optional |
Unattributable
Other
Execution 85ms
Transfer 0 KB
Monthly Cost $0/mo
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.