Skip to content
https://docs.rs

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
99
GRADE
A+
FIX
0
REVIEW
1
PASS
14
INFO
2

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

Mobile Desktop
91
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.
91
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.

1.06 s

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

3.46 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.

0.027

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

1.06 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.

3.46 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
17
14 PASS 1 REVIEW
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Page Weight Budget
536 KB transferred, 13 requests
PASS
536 KB transferred, 13 requests
Info::
Page weighs 681 KB (536 KB transferred)
Info::
Fonts are 485 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 485 KB
Info::
13 HTTP requests
Info::
Estimated 0.11 g CO2 per page load
536 KB / 2.4 MB budget
536 KB transferred
13 requests
0.11 g CO2 per page load
Fonts 485.0 KiB 91%
CSS 40.1 KiB 7%
JavaScript 5.7 KiB 1%
HTML 3.9 KiB 1%
Other 1.2 KiB 0%
0 2.4 MB 4.9 MB
Under budget

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

A+
Third-Party Impact
No third-party resources
PASS
No third-party resources
Info::
No third-party resources detected
No third-party resources detected — all resources are first-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
No images on this page
PASS
No images on this page
Info::
No images on this page
0 images 0 KB
0 oversized -0 KB
0 legacy format
0 missing dimensions CLS risk
A+
JS Execution Cost
407ms total JS execution
PASS
407ms total JS execution
Info::
https://docs.rs/: 249ms CPU time
Info::
Unattributable: 158ms CPU time
Info::
Third-party scripts: 158ms (39% of total)

Main Thread Breakdown

Other 46% Style & Layout 36% Parse HTML & CSS 6% Rendering 6% Script Evaluation 5%
ScriptTotalScriptingParse/CompileParty
https://docs.rs/249ms11ms1ms1st
Unattributable158ms6ms0ms3rd
A+
Font Loading
4 fonts (485 KB)
PASS
4 fonts (485 KB)
Info::
4 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

4

485 KB total

Render-blocking

0

of 4

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 1.0 s 2.0 s 3.0 s FCP 1.1 s LCP 3.5 shttps://docs.rs/-/static/FiraSans-Regular.woff2FiraSans-Regular.woff2 https://docs.rs/-/static/FiraSans-Regular.woff2 — 126.6 KiB — 25 ms — font-display: swaphttps://docs.rs/-/static/fa-solid-900.woff2fa-solid-900.woff2 https://docs.rs/-/static/fa-solid-900.woff2 — 153.8 KiB — 37 ms — font-display: swaphttps://docs.rs/-/static/FiraSans-Medium.woff2FiraSans-Medium.woff2 https://docs.rs/-/static/FiraSans-Medium.woff2 — 130.0 KiB — 30 ms — font-display: swaphttps://docs.rs/-/static/SourceSerif4-Regular.ttf.woff2SourceSerif4-Regular.tt... https://docs.rs/-/static/SourceSerif4-Regular.ttf.woff2 — 74.6 KiB — 22 ms — font-display: swap
FiraSans-Regular.woff2 woff2 swap
Size 127 KB
Load time 25 ms
Start 113 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
fa-solid-900.woff2 woff2 swap
Size 154 KB
Load time 37 ms
Start 113 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
FiraSans-Medium.woff2 woff2 swap
Size 130 KB
Load time 30 ms
Start 113 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
SourceSerif4-Regular.tt... woff2 swap
Size 75 KB
Load time 22 ms
Start 115 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)

Fixing the unchecked items could save ~205 KB and ~410 ms

A
JS Bundles
3 scripts, 0 KB unused
PASS
3 scripts, 0 KB unused
Warning::
https://docs.rs/-/static/menu.js?0-0-0-9a14b3d3fb8...: unminified — 2 KB could be saved
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://docs.rs/-/static/keyboard.js?0-0-0-9a14b3d3fb884a3034195abfb368439d6d1cca28-2026-04-211 KB—✓1st
https://docs.rs/-/static/menu.js?0-0-0-9a14b3d3fb884a3034195abfb368439d6d1cca28-2026-04-214 KB—✗1st
https://docs.rs/-/static/index.js?0-0-0-9a14b3d3fb884a3034195abfb368439d6d1cca28-2026-04-211 KB—✓1st
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
13 resources · 536 KB · 0 KB savings available
PASS
13 resources · 536 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 536 KB
13 resources · 535.8 KiB · 0 third-party Within 1MB page-weight target
Font 91% · 485.0 KiB
CSS 7% · 40.1 KiB
JavaScript 1% · 5.7 KiB
Document 1% · 3.9 KiB
Image 0% · 994 B
Other 0% · 200 B
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
A
HTTP Caching
max-age=60 (1 minute)
PASS
max-age=60 (1 minute)
Info::
Cache-Control header is set
Got: public, max-age=60
Info::
Effective TTL: 1 minute (max-age=60)
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

public, max-age=60

DirectiveValueMeaning
public—Any cache may store this response
max-age60Cache for 1 minute
Effective TTL: 60 seconds
Network Waterfall
13 requests over 308ms
INFO
0 ms 1.0 s 2.0 s 3.0 s FCP 1.1 s LCP 3.5 shttps://docs.rs// https://docs.rs/ — 200 — 3.9 KiB — 32 ms — h2https://docs.rs/-/static/vendored.css?0-0-0-9a14b3d3fb884a3034195abfb368439d6d1cca28-2026-04-21/-/static/vendored.css?0-0-0-9a14b3... https://docs.rs/-/static/vendored.css?0-0-0-9a14b3d3fb884a3034195abfb368439d6d1cca28-2026-04-21 — 200 — 6.1 KiB — 15 ms — h2https://docs.rs/-/static/style.css?0-0-0-9a14b3d3fb884a3034195abfb368439d6d1cca28-2026-04-21/-/static/style.css?0-0-0-9a14b3d3f... https://docs.rs/-/static/style.css?0-0-0-9a14b3d3fb884a3034195abfb368439d6d1cca28-2026-04-21 — 200 — 7.3 KiB — 17 ms — h2https://docs.rs/-/static/font-awesome.css?0-0-0-9a14b3d3fb884a3034195abfb368439d6d1cca28-2026-04-21/-/static/font-awesome.css?0-0-0-9a... https://docs.rs/-/static/font-awesome.css?0-0-0-9a14b3d3fb884a3034195abfb368439d6d1cca28-2026-04-21 — 200 — 26.6 KiB — 14 ms — h2https://docs.rs/-/static/keyboard.js?0-0-0-9a14b3d3fb884a3034195abfb368439d6d1cca28-2026-04-21/-/static/keyboard.js?0-0-0-9a14b3d... https://docs.rs/-/static/keyboard.js?0-0-0-9a14b3d3fb884a3034195abfb368439d6d1cca28-2026-04-21 — 200 — 1.4 KiB — 11 ms — h2https://docs.rs/-/static/menu.js?0-0-0-9a14b3d3fb884a3034195abfb368439d6d1cca28-2026-04-21/-/static/menu.js?0-0-0-9a14b3d3fb8... https://docs.rs/-/static/menu.js?0-0-0-9a14b3d3fb884a3034195abfb368439d6d1cca28-2026-04-21 — 200 — 3.7 KiB — 8 ms — h2https://docs.rs/-/static/index.js?0-0-0-9a14b3d3fb884a3034195abfb368439d6d1cca28-2026-04-21/-/static/index.js?0-0-0-9a14b3d3fb... https://docs.rs/-/static/index.js?0-0-0-9a14b3d3fb884a3034195abfb368439d6d1cca28-2026-04-21 — 200 — 628 B — 8 ms — h2https://docs.rs/-/static/FiraSans-Regular.woff2/-/static/FiraSans-Regular.woff2 https://docs.rs/-/static/FiraSans-Regular.woff2 — 200 — 126.6 KiB — 25 ms — h2https://docs.rs/-/static/fa-solid-900.woff2/-/static/fa-solid-900.woff2 https://docs.rs/-/static/fa-solid-900.woff2 — 200 — 153.8 KiB — 37 ms — h2https://docs.rs/-/static/FiraSans-Medium.woff2/-/static/FiraSans-Medium.woff2 https://docs.rs/-/static/FiraSans-Medium.woff2 — 200 — 130.0 KiB — 30 ms — h2https://docs.rs/-/static/SourceSerif4-Regular.ttf.woff2/-/static/SourceSerif4-Regular.ttf.... https://docs.rs/-/static/SourceSerif4-Regular.ttf.woff2 — 200 — 74.6 KiB — 22 ms — h2https://docs.rs/favicon.ico/favicon.ico https://docs.rs/favicon.ico — 308 — 200 B — 124 ms — h2https://docs.rs/-/static/favicon.ico/-/static/favicon.ico https://docs.rs/-/static/favicon.ico — 200 — 994 B — 7 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
39% of JavaScript execution is third-party
First-party Third-party 158ms · 0KB · din226/mo
Unattributable
Other
Costly
Execution 158ms
Transfer 0 KB
Monthly Cost din226/mo

These scripts may cost more than they're worth

  • Unattributable adds 158ms and costs ~din226/month

Unattributable takes 158ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback