Skip to content
https://gitter.im

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
91
GRADE
A
FIX
1
REVIEW
2
PASS
10
INFO
1

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

100
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
81
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
73
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.

501 ms

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

791 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.

0.000

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

501 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.

791 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
10 PASS 2 REVIEW 1 FIX
D
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.
Info::
ETag present — enables conditional (304) responses
Info::
Last-Modified header present

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
Image Optimization
Action
20 images, 0 KB saveable
REVIEW
20 images, 0 KB saveable
Warning::
https://gitter.im/images/trusted-by-logos/trusted-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://gitter.im/images/gitter-apps.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://gitter.im/images/testimonials/testimonial-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://gitter.im/images/testimonials/testimonial-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://gitter.im/images/trusted-by-logos/trusted-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://gitter.im/images/trusted-by-logos/trusted-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://gitter.im/images/trusted-by-logos/trusted-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://gitter.im/images/testimonials/testimonial-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://gitter.im/images/logo-text-white-nomargin@... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://gitter.im/images/testimonials/testimonial-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://gitter.im/images/trusted-by-logos/trusted-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://gitter.im/images/testimonials/testimonial-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://gitter.im/images/testimonials/testimonial-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://gitter.im/images/testimonials/testimonial-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://gitter.im/images/trusted-by-logos/trusted-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://gitter.im/images/trusted-by-logos/trusted-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
20 images 895 KB
0 oversized -0 KB
20 legacy format
16 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

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

Green Hosting

No green hosting detected

A
Page Weight Budget
935 KB transferred, 27 requests
PASS
935 KB transferred, 27 requests
Info::
Page weighs 948 KB (935 KB transferred)
Info::
27 HTTP requests
Info::
Estimated 0.19 g CO2 per page load
935 KB / 2.4 MB budget
935 KB transferred
27 requests
0.19 g CO2 per page load
Images 895.4 KiB 96%
CSS 22.3 KiB 2%
HTML 9.1 KiB 1%
Other 8.3 KiB 1%
Fonts 0 B 0%
0 2.4 MB 4.9 MB
Under budget
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+
JS Execution Cost
138ms total JS execution
PASS
138ms total JS execution
Info::
https://gitter.im/: 138ms CPU time

Main Thread Breakdown

Other 50% Style & Layout 32% Rendering 14%
ScriptTotalScriptingParse/CompileParty
https://gitter.im/138ms3ms0ms1st
A+
Font Loading
3 fonts (0 KB)
PASS
3 fonts (0 KB)
Info::
3 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

3

0 KB total

Render-blocking

0

of 3

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s FCP 501 ms LCP 791 mshttps://cdn03.gitter.im/_s/0f349ae51/fonts/sourcesans/SourceSansPro-Bold.otf.woffSourceSansPro-Bold.otf.... https://cdn03.gitter.im/_s/0f349ae51/fonts/sourcesans/SourceSansPro-Bold.otf.woff — 0 B — 46 ms — font-display: swaphttps://cdn02.gitter.im/_s/0f349ae51/fonts/sourcesans/SourceSansPro-Regular.otf.woffSourceSansPro-Regular.o... https://cdn02.gitter.im/_s/0f349ae51/fonts/sourcesans/SourceSansPro-Regular.otf.woff — 0 B — 38 ms — font-display: swaphttps://cdn02.gitter.im/_s/0f349ae51/fonts/sourcesans/SourceSansPro-Semibold.otf.woffSourceSansPro-Semibold.... https://cdn02.gitter.im/_s/0f349ae51/fonts/sourcesans/SourceSansPro-Semibold.otf.woff — 0 B — 35 ms — font-display: swap
SourceSansPro-Bold.otf.... woff swap
Size 0 KB
Load time 46 ms
Start 201 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
SourceSansPro-Regular.o... woff swap
Size 0 KB
Load time 38 ms
Start 205 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
SourceSansPro-Semibold.... woff swap
Size 0 KB
Load time 35 ms
Start 208 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
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+
JS Bundles
No JavaScript
PASS
No JavaScript
Info::
No JavaScript bundles
No JavaScript files loaded.
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
27 resources · 935 KB · 0 KB savings available
PASS
27 resources · 935 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 935 KB
Info::
3 third-party resources (0% of weight)
Info::
2 resources over 200KB
27 resources · 935.1 KiB · 3 third-party Within 1MB page-weight target
Image 97% · 903.7 KiB
CSS 2% · 22.3 KiB
Document 1% · 9.1 KiB
Font 0% · 0 B
Network Waterfall
27 requests over 360ms
INFO
0 ms 200 ms 400 ms 600 ms 800 ms FCP 501 ms LCP 791 mshttps://gitter.im// https://gitter.im/ — 200 — 9.1 KiB — 144 ms — h2https://gitter.im/_astro/styleguide.6d44e7d5.css/_astro/styleguide.6d44e7d5.css https://gitter.im/_astro/styleguide.6d44e7d5.css — 200 — 13.2 KiB — 67 ms — h2https://gitter.im/_astro/index.d2ae4499.css/_astro/index.d2ae4499.css https://gitter.im/_astro/index.d2ae4499.css — 200 — 9.1 KiB — 67 ms — h2https://gitter.im/images/logo-text-white-nomargin@2x.png/images/logo-text-white-nomargin@2x... https://gitter.im/images/logo-text-white-nomargin@2x.png — 200 — 720 B — 68 ms — h2https://gitter.im/images/map.png/images/map.png https://gitter.im/images/map.png — 200 — 13.2 KiB — 68 ms — h2https://gitter.im/images/trusted-by-logos/trusted-by-airbnb.png/images/trusted-by-logos/trusted-by... https://gitter.im/images/trusted-by-logos/trusted-by-airbnb.png — 200 — 7.5 KiB — 66 ms — h2https://gitter.im/images/trusted-by-logos/trusted-by-aws.png/images/trusted-by-logos/trusted-by... https://gitter.im/images/trusted-by-logos/trusted-by-aws.png — 200 — 10.6 KiB — 101 ms — h2https://gitter.im/images/trusted-by-logos/trusted-by-google.png/images/trusted-by-logos/trusted-by... https://gitter.im/images/trusted-by-logos/trusted-by-google.png — 200 — 9.0 KiB — 130 ms — h2https://gitter.im/images/trusted-by-logos/trusted-by-microsoft.png/images/trusted-by-logos/trusted-by... https://gitter.im/images/trusted-by-logos/trusted-by-microsoft.png — 200 — 7.8 KiB — 74 ms — h2https://gitter.im/images/trusted-by-logos/trusted-by-mozilla-science-lab.png/images/trusted-by-logos/trusted-by... https://gitter.im/images/trusted-by-logos/trusted-by-mozilla-science-lab.png — 200 — 14.4 KiB — 130 ms — h2https://gitter.im/images/trusted-by-logos/trusted-by-rails.png/images/trusted-by-logos/trusted-by... https://gitter.im/images/trusted-by-logos/trusted-by-rails.png — 200 — 5.6 KiB — 126 ms — h2https://gitter.im/images/trusted-by-logos/trusted-by-scala.png/images/trusted-by-logos/trusted-by... https://gitter.im/images/trusted-by-logos/trusted-by-scala.png — 200 — 5.1 KiB — 126 ms — h2https://gitter.im/images/gitter-apps.png/images/gitter-apps.png https://gitter.im/images/gitter-apps.png — 200 — 299.9 KiB — 163 ms — h2https://gitter.im/images/testimonials/testimonial-chrisvnicholson.jpg/images/testimonials/testimonial-ch... https://gitter.im/images/testimonials/testimonial-chrisvnicholson.jpg — 200 — 35.0 KiB — 162 ms — h2https://gitter.im/images/testimonials/testimonial-dreadknight.jpg/images/testimonials/testimonial-dr... https://gitter.im/images/testimonials/testimonial-dreadknight.jpg — 200 — 61.7 KiB — 99 ms — h2https://gitter.im/images/testimonials/testimonial-ttmc.jpg/images/testimonials/testimonial-tt... https://gitter.im/images/testimonials/testimonial-ttmc.jpg — 200 — 13.4 KiB — 144 ms — h2https://gitter.im/images/testimonials/testimonial-krishnasrinivas.jpg/images/testimonials/testimonial-kr... https://gitter.im/images/testimonials/testimonial-krishnasrinivas.jpg — 200 — 10.2 KiB — 142 ms — h2https://gitter.im/images/testimonials/testimonial-samccone.jpeg/images/testimonials/testimonial-sa... https://gitter.im/images/testimonials/testimonial-samccone.jpeg — 200 — 32.9 KiB — 109 ms — h2https://gitter.im/images/testimonials/testimonial-diasdavid.jpeg/images/testimonials/testimonial-di... https://gitter.im/images/testimonials/testimonial-diasdavid.jpeg — 200 — 17.9 KiB — 143 ms — h2https://gitter.im/images/testimonials/testimonial-doge.jpeg/images/testimonials/testimonial-do... https://gitter.im/images/testimonials/testimonial-doge.jpeg — 200 — 11.5 KiB — 141 ms — h2https://gitter.im/images/clouds-banner.jpg/images/clouds-banner.jpg https://gitter.im/images/clouds-banner.jpg — 200 — 292.1 KiB — 121 ms — h2https://gitter.im/images/matrix-hero-spiro.svg/images/matrix-hero-spiro.svg https://gitter.im/images/matrix-hero-spiro.svg — 200 — 46.5 KiB — 121 ms — h2https://gitter.im/images/quote-arrow.png/images/quote-arrow.png https://gitter.im/images/quote-arrow.png — 200 — 391 B — 90 ms — h2https://cdn03.gitter.im/_s/0f349ae51/fonts/sourcesans/SourceSansPro-Bold.otf.woffcdn03.gitter.im/_s/0f349ae51/fonts/... https://cdn03.gitter.im/_s/0f349ae51/fonts/sourcesans/SourceSansPro-Bold.otf.woff — -1 — 0 B — 46 ms — https://cdn02.gitter.im/_s/0f349ae51/fonts/sourcesans/SourceSansPro-Regular.otf.woffcdn02.gitter.im/_s/0f349ae51/fonts/... https://cdn02.gitter.im/_s/0f349ae51/fonts/sourcesans/SourceSansPro-Regular.otf.woff — -1 — 0 B — 38 ms — https://cdn02.gitter.im/_s/0f349ae51/fonts/sourcesans/SourceSansPro-Semibold.otf.woffcdn02.gitter.im/_s/0f349ae51/fonts/... https://cdn02.gitter.im/_s/0f349ae51/fonts/sourcesans/SourceSansPro-Semibold.otf.woff — -1 — 0 B — 35 ms — https://gitter.im/favicon-normal.ico/favicon-normal.ico https://gitter.im/favicon-normal.ico — 200 — 8.3 KiB — 35 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.

Send Feedback