Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

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

Mobile Desktop

Performance

100

Accessibility

100

Best Practices

100

SEO

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

539 ms

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

1.16 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.

0.000

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

678 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.

1.16 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

9 PASS 2 REVIEW 2 FIX

Page Weight Budget

Action

2.7 MB transferred, 116 requests

FIX

2.7 MB transferred, 116 requests

Page weighs 2.9 MB (2.7 MB transferred)

Images are 2.4 MB — compress or use modern formats

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Got: 2.4 MB

Fonts are 222 KB — consider subsetting or using system fonts

Subset fonts to include only used characters, or switch to system font stacks.

Got: 222 KB

116 HTTP requests — consider bundling or reducing

Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.

Estimated 0.57 g CO2 per page load

2.7 MB transferred

116 requests

0.57 g CO2 per page load

Images 2.4 MiB 87%

Fonts 221.7 KiB 8%

CSS 55.2 KiB 2%

JavaScript 46.1 KiB 2%

HTML 24.1 KiB 1%

Other 14.9 KiB 1%

Other 2.5 KiB 0%

Other 479 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

Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.

Why this matters

High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.

Source: web.dev

HTTP Caching

Action

No cache headers

FIX

No cache headers

No Cache-Control header found

Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

ETag present — enables conditional (304) responses

Last-Modified header present

No Cache-Control header

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

Image Optimization

26 images, 0 KB saveable

REVIEW

26 images, 0 KB saveable

https://basecamp.com/assets/images/home/illustrati... is missing width/height — may cause layout shift

Set explicit width and height to prevent CLS.

26 images 2.4 MB

0 oversized -0 KB

11 legacy format

1 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

Page Weight Inventory

Action

116 resources · 2.7 MB · 0 KB savings available

REVIEW

116 resources · 2.7 MB · 0 KB savings available

Page weight 1.7 MB over 1MB target

Got: 2.7 MB Expected: ≤ 1 MB

1 third-party resources (0% of weight)

2 resources over 200KB

116 resources · 2.7 MiB · 1 third-party 1.7 MiB over 1MB target

Image 87% · 2.4 MiB

Font 8% · 221.7 KiB

CSS 2% · 55.2 KiB

JavaScript 2% · 46.1 KiB

Document 1% · 24.1 KiB

Other 0% · 3.0 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

116 resources			2.7 MiB

A+

Third-Party Impact

0% third-party, 0 ms blocking

PASS

0% third-party, 0 ms blocking

Third-party code accounts for 0% of page weight (2.5 KiB of 2.7 MiB)

Third-party blocking time is low (0 ms)

100%

First-party Third-party

A+

Text Compression

All text resources are compressed

PASS

All text resources are compressed

All text resources are properly compressed.

A+

JS Execution Cost

234ms total JS execution

PASS

234ms total JS execution

https://basecamp.com/: 128ms CPU time

Unattributable: 106ms CPU time

Third-party scripts: 106ms (45% of total)

Main Thread Breakdown

Other 49% Style & Layout 31% Script Evaluation 10% Rendering 7% Parse HTML & CSS 3%

Script	Total	Scripting	Parse/Compile	Party
https://basecamp.com/	128ms	2ms	0ms	1st
Unattributable	106ms	7ms	0ms	3rd

A+

Font Loading

6 fonts (222 KB)

PASS

6 fonts (222 KB)

6 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

222 KB total

Render-blocking

of 6

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

Graphik-Semibold-Web.woff2 woff2 swap

Size 40 KB

Load time 158 ms

Start 384 ms