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https://jekyllrb.com

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
92
GRADE
A
FIX
0
REVIEW
4
PASS
9
INFO
1

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

Mobile Desktop
100
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
91
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.
100
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.

334 ms

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

588 ms

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.

0.003

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

334 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.

588 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 s
Checks
14
9 PASS 4 REVIEW
B
Third-Party Impact
49% third-party, 0 ms blocking
REVIEW
49% third-party, 0 ms blocking
Info::
Third-party code accounts for 49% of page weight (217.3 KiB of 440.0 KiB)
Info::
Third-party blocking time is low (0 ms)
51%
49%
First-party Third-party
B
Image Optimization
4 images, 0 KB saveable
REVIEW
4 images, 0 KB saveable
Info::
All images are well-optimized
4 images 72 KB
0 oversized -0 KB
4 legacy format
0 missing dimensions CLS risk
B
JS Bundles
3 scripts, 90 KB unused
REVIEW
3 scripts, 90 KB unused
Warning::
https://www.googletagmanager.com/gtag/js?id=G-GJE5...: 64 KB unused (43%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn.jsdelivr.net/npm/docsearch.js@2/dist/c...: 26 KB unused (56%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 90 KB
90 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtag/js?id=G-GJE5T10EDG&cx=c&_slc=1148 KB64 KB (43%)✓3rd
https://cdn.jsdelivr.net/npm/docsearch.js@2/dist/cdn/docsearch.min.js47 KB26 KB (56%)✓3rd
https://www.google-analytics.com/analytics.js21 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

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

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Page Weight Budget
440 KB transferred, 18 requests
PASS
440 KB transferred, 18 requests
Info::
Page weighs 918 KB (440 KB transferred)
Info::
18 HTTP requests
Info::
Estimated 0.09 g CO2 per page load
440 KB / 2.4 MB budget
440 KB transferred
18 requests
0.09 g CO2 per page load
JavaScript 216.4 KiB 49%
Fonts 131.5 KiB 30%
Images 71.9 KiB 16%
CSS 13.8 KiB 3%
HTML 3.7 KiB 1%
Other 1.7 KiB 0%
Other 547 B 0%
Other 463 B 0%
0 2.4 MB 4.9 MB
Under budget
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+
JS Execution Cost
53ms total JS execution
PASS
53ms total JS execution
Info::
https://jekyllrb.com/: 53ms CPU time

Main Thread Breakdown

Script Evaluation 48% Style & Layout 20% Other 19% Script Parsing & Compilation 9%
ScriptTotalScriptingParse/CompileParty
https://jekyllrb.com/53ms10ms1ms1st
A+
Font Loading
6 fonts (131 KB)
PASS
6 fonts (131 KB)
Info::
6 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

6

131 KB total

Render-blocking

0

of 6

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s FCP 334 ms LCP 588 mshttps://jekyllrb.com/fonts/lato-v14-latin-300.woff2lato-v14-latin-300.woff2 https://jekyllrb.com/fonts/lato-v14-latin-300.woff2 — 22.9 KiB — 7 ms — font-display: swaphttps://jekyllrb.com/fonts/lato-v14-latin-700.woff2lato-v14-latin-700.woff2 https://jekyllrb.com/fonts/lato-v14-latin-700.woff2 — 22.4 KiB — 8 ms — font-display: swaphttps://jekyllrb.com/fonts/lato-v14-latin-900.woff2lato-v14-latin-900.woff2 https://jekyllrb.com/fonts/lato-v14-latin-900.woff2 — 22.0 KiB — 8 ms — font-display: swaphttps://jekyllrb.com/fonts/lato-v14-latin-300italic.woff2lato-v14-latin-300itali... https://jekyllrb.com/fonts/lato-v14-latin-300italic.woff2 — 17.3 KiB — 8 ms — font-display: swaphttps://jekyllrb.com/fonts/lato-v14-latin-700italic.woff2lato-v14-latin-700itali... https://jekyllrb.com/fonts/lato-v14-latin-700italic.woff2 — 23.9 KiB — 7 ms — font-display: swaphttps://jekyllrb.com/fonts/lato-v14-latin-regular.woff2lato-v14-latin-regular.... https://jekyllrb.com/fonts/lato-v14-latin-regular.woff2 — 23.0 KiB — 5 ms — font-display: swap
lato-v14-latin-300.woff2 woff2 swap
Size 23 KB
Load time 7 ms
Start 14 ms
Risk FOUT — text flashes from fallback to web font
lato-v14-latin-700.woff2 woff2 swap
Size 22 KB
Load time 8 ms
Start 14 ms
Risk FOUT — text flashes from fallback to web font
lato-v14-latin-900.woff2 woff2 swap
Size 22 KB
Load time 8 ms
Start 63 ms
Risk FOUT — text flashes from fallback to web font
lato-v14-latin-300itali... woff2 swap
Size 17 KB
Load time 8 ms
Start 63 ms
Risk FOUT — text flashes from fallback to web font
lato-v14-latin-700itali... woff2 swap
Size 24 KB
Load time 7 ms
Start 63 ms
Risk FOUT — text flashes from fallback to web font
lato-v14-latin-regular.... woff2 swap
Size 23 KB
Load time 5 ms
Start 63 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
Page Weight Inventory
18 resources · 440 KB · 90 KB savings available
PASS
18 resources · 440 KB · 90 KB savings available
Info::
Within 1MB page-weight target
Got: 440 KB
Info::
~90 KB of savings available
Warning::
5 third-party resources (49% of weight)
18 resources · 440.0 KiB · 5 third-party Within 1MB page-weight target
JavaScript 49% · 216.4 KiB
Font 30% · 131.5 KiB
Image 17% · 73.6 KiB
CSS 3% · 13.8 KiB
Document 1% · 3.7 KiB
Other 0% · 1010 B

~90.2 KiB of savings available

Remove unused JavaScript: 90.2 KiB
A+
HTTP Caching
max-age=600 (10 minutes)
PASS
max-age=600 (10 minutes)
Info::
Cache-Control header is set
Got: max-age=600
Info::
Effective TTL: 10 minutes (max-age=600)
Info::
ETag present — enables conditional (304) responses
Info::
Last-Modified header present
Cache-Control

max-age=600

DirectiveValueMeaning
max-age600Cache for 10 minutes
Effective TTL: 600 seconds
Network Waterfall
18 requests over 460ms
INFO
0 ms 200 ms 400 ms 600 ms FCP 334 ms LCP 588 mshttps://jekyllrb.com// https://jekyllrb.com/ — 200 — 3.7 KiB — 5 ms — h2https://jekyllrb.com/fonts/lato-v14-latin-300.woff2/fonts/lato-v14-latin-300.woff2 https://jekyllrb.com/fonts/lato-v14-latin-300.woff2 — 200 — 22.9 KiB — 7 ms — h2https://jekyllrb.com/fonts/lato-v14-latin-700.woff2/fonts/lato-v14-latin-700.woff2 https://jekyllrb.com/fonts/lato-v14-latin-700.woff2 — 200 — 22.4 KiB — 8 ms — h2https://jekyllrb.com/css/screen.css/css/screen.css https://jekyllrb.com/css/screen.css — 200 — 13.8 KiB — 11 ms — h2https://jekyllrb.com/img/octojekyll.png/img/octojekyll.png https://jekyllrb.com/img/octojekyll.png — 200 — 22.0 KiB — 8 ms — h2https://cdn.jsdelivr.net/npm/docsearch.js@2/dist/cdn/docsearch.min.jscdn.jsdelivr.net/npm/docsearch.js@2... https://cdn.jsdelivr.net/npm/docsearch.js@2/dist/cdn/docsearch.min.js — 200 — 47.5 KiB — 30 ms — h2https://jekyllrb.com/img/logo-2x.png/img/logo-2x.png https://jekyllrb.com/img/logo-2x.png — 200 — 45.1 KiB — 9 ms — h2https://jekyllrb.com/img/footer-logo.png/img/footer-logo.png https://jekyllrb.com/img/footer-logo.png — 200 — 3.7 KiB — 10 ms — h2https://jekyllrb.com/img/footer-arrow.png/img/footer-arrow.png https://jekyllrb.com/img/footer-arrow.png — 200 — 1.0 KiB — 130 ms — h2https://jekyllrb.com/fonts/lato-v14-latin-900.woff2/fonts/lato-v14-latin-900.woff2 https://jekyllrb.com/fonts/lato-v14-latin-900.woff2 — 200 — 22.0 KiB — 8 ms — h2https://jekyllrb.com/fonts/lato-v14-latin-300italic.woff2/fonts/lato-v14-latin-300italic.wof... https://jekyllrb.com/fonts/lato-v14-latin-300italic.woff2 — 200 — 17.3 KiB — 8 ms — h2https://jekyllrb.com/fonts/lato-v14-latin-700italic.woff2/fonts/lato-v14-latin-700italic.wof... https://jekyllrb.com/fonts/lato-v14-latin-700italic.woff2 — 200 — 23.9 KiB — 7 ms — h2https://jekyllrb.com/fonts/lato-v14-latin-regular.woff2/fonts/lato-v14-latin-regular.woff2 https://jekyllrb.com/fonts/lato-v14-latin-regular.woff2 — 200 — 23.0 KiB — 5 ms — h2https://www.google-analytics.com/analytics.jswww.google-analytics.com/analytics.... https://www.google-analytics.com/analytics.js — 200 — 20.9 KiB — 83 ms — h2https://www.google-analytics.com/j/collect?v=1&_v=j102&a=858781997&t=pageview&_s=1&dl=https%3A%2F%2Fjekyllrb.com%2F&ul=en-us&dt=Jekyll%20%E2%80%A2%20Simple%2C%20blog-aware%2C%20static%20sites%20%7C%20Transform%20your%20plain%20text%20into%20static%20websites%20and%20blogs&sr=800x600&vp=1350x940&_u=IEBAAAABAAAAACAAI~&jid=1956920437&gjid=1454696348&cid=1312972203.1776816396&tid=UA-50755011-1&_gid=266577774.1776816396&_r=1&_slc=1&z=1109667296www.google-analytics.com/j/collect?... https://www.google-analytics.com/j/collect?v=1&_v=j102&a=858781997&t=pageview&_s=1&dl=https%3A%2F%2Fjekyllrb.com%2F&ul=en-us&dt=Jekyll%20%E2%80%A2%20Simple%2C%20blog-aware%2C%20static%20sites%20%7C%20Transform%20your%20plain%20text%20into%20static%20websites%20and%20blogs&sr=800x600&vp=1350x940&_u=IEBAAAABAAAAACAAI~&jid=1956920437&gjid=1454696348&cid=1312972203.1776816396&tid=UA-50755011-1&_gid=266577774.1776816396&_r=1&_slc=1&z=1109667296 — 200 — 463 B — 25 ms — h2https://jekyllrb.com/favicon.ico/favicon.ico https://jekyllrb.com/favicon.ico — 200 — 1.7 KiB — 2 ms — h2https://www.googletagmanager.com/gtag/js?id=G-GJE5T10EDG&cx=c&_slc=1www.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-GJE5T10EDG&cx=c&_slc=1 — 200 — 148.0 KiB — 142 ms — h2https://region1.google-analytics.com/g/collect?v=2&tid=G-GJE5T10EDG&gtm=45je64h1h1v9124045930za20g&_p=1776816396489&gcd=13l3l3l2l2l1&npa=0&dma_cps=a&dma=1&_eu=EBAI&are=1&cid=1312972203.1776816396&frm=0&ir=1&pscdl=noapi&rcb=0&sr=800x600&uaa=x86&uab=64&uafvl=Chromium%3B147.0.7727.101%7CNot.A%252FBrand%3B8.0.0.0&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=0~115938465~115938468~117266400~117512542&dl=https%3A%2F%2Fjekyllrb.com%2F&dt=Jekyll%20%E2%80%A2%20Simple%2C%20blog-aware%2C%20static%20sites%20%7C%20Transform%20your%20plain%20text%20into%20static%20websites%20and%20blogs&sid=1776816396&sct=1&seg=0&_tu=wAQ&en=page_view&_fv=1&_ss=1&_ee=1&tfd=395region1.google-analytics.com/g/coll... https://region1.google-analytics.com/g/collect?v=2&tid=G-GJE5T10EDG&gtm=45je64h1h1v9124045930za20g&_p=1776816396489&gcd=13l3l3l2l2l1&npa=0&dma_cps=a&dma=1&_eu=EBAI&are=1&cid=1312972203.1776816396&frm=0&ir=1&pscdl=noapi&rcb=0&sr=800x600&uaa=x86&uab=64&uafvl=Chromium%3B147.0.7727.101%7CNot.A%252FBrand%3B8.0.0.0&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=0~115938465~115938468~117266400~117512542&dl=https%3A%2F%2Fjekyllrb.com%2F&dt=Jekyll%20%E2%80%A2%20Simple%2C%20blog-aware%2C%20static%20sites%20%7C%20Transform%20your%20plain%20text%20into%20static%20websites%20and%20blogs&sid=1776816396&sct=1&seg=0&_tu=wAQ&en=page_view&_fv=1&_ss=1&_ee=1&tfd=395 — 204 — 547 B — 65 ms — h2
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.

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