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Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
89
GRADE
B
FIX
1
REVIEW
4
PASS
8
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.
63
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.
83
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.

1.09 s

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

1.47 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.

0.079

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

1.09 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.

1.47 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
15
8 PASS 4 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
Page Weight Budget
Action
1.9 MB transferred, 25 requests
REVIEW
1.9 MB transferred, 25 requests
Info::
Page weighs 2.0 MB (1.9 MB transferred)
Warning::
Images are 1.4 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 1.4 MB
Info::
Fonts are 327 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 327 KB
Info::
25 HTTP requests
Info::
Estimated 0.40 g CO2 per page load
1.9 MB / 2.4 MB budget
1.9 MB transferred
25 requests
0.40 g CO2 per page load
Images 1.4 MiB 73%
Fonts 326.9 KiB 17%
Other 139.7 KiB 7%
JavaScript 38.7 KiB 2%
HTML 10.1 KiB 1%
CSS 9.8 KiB 1%
Other 1.1 KiB 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Approaching limit

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

C
Image Optimization
Action
9 images, 0 KB saveable
REVIEW
9 images, 0 KB saveable
Warning::
https://martinfowler.com/img/mf-dallas.jpg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://martinfowler.com/photos/131.jpg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://martinfowler.com/articles/mechanical-sympa... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://martinfowler.com/articles/harness-engineer... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://martinfowler.com/thoughtworks_white.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://martinfowler.com/mf-name-white.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://martinfowler.com/architecture/oscon.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://martinfowler.com/board-games.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
9 images 1.4 MB
0 oversized -0 KB
9 legacy format
8 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

C
Page Weight Inventory
Action
25 resources · 1.9 MB · 21 KB savings available
REVIEW
25 resources · 1.9 MB · 21 KB savings available
Warning::
Page weight 906 KB over 1MB target
Got: 1.9 MB Expected: ≤ 1 MB
Info::
11 third-party resources (17% of weight)
Info::
4 resources over 200KB
25 resources · 1.9 MiB · 11 third-party 905.8 KiB over 1MB target
Image 80% · 1.5 MiB
Font 17% · 326.9 KiB
JavaScript 2% · 38.7 KiB
Document 1% · 10.1 KiB
CSS 1% · 9.8 KiB
Other 0% · 1.1 KiB

~20.8 KiB of savings available

Remove unused JavaScript: 20.8 KiB
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Third-Party Impact
17% third-party, 0 ms blocking
PASS
17% third-party, 0 ms blocking
Info::
Third-party code accounts for 17% of page weight (336.2 KiB of 1.9 MiB)
Info::
Third-party blocking time is low (0 ms)
83%
17%
First-party Third-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
217ms total JS execution
PASS
217ms total JS execution
Info::
https://martinfowler.com/: 141ms CPU time
Info::
Unattributable: 76ms CPU time
Info::
Third-party scripts: 76ms (35% of total)

Main Thread Breakdown

Style & Layout 45% Other 33% Script Evaluation 10% Rendering 7%
ScriptTotalScriptingParse/CompileParty
https://martinfowler.com/141ms1ms0ms1st
Unattributable76ms2ms0ms3rd
A+
Font Loading
5 fonts (327 KB)
PASS
5 fonts (327 KB)
Info::
5 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

5

327 KB total

Render-blocking

0

of 5

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s 1.5 s FCP 1.1 s LCP 1.5 shttps://cdn.jsdelivr.net/npm/remixicon@4.3.0/fonts/remixicon.woff2?t=1590207869815remixicon.woff2 https://cdn.jsdelivr.net/npm/remixicon@4.3.0/fonts/remixicon.woff2?t=1590207869815 — 162.5 KiB — 50 ms — font-display: swaphttps://fonts.gstatic.com/s/lora/v37/0QIvMX1D_JOuMwr7I_FMl_E.woff20QIvMX1D_JOuMwr7I_FMl_E... https://fonts.gstatic.com/s/lora/v37/0QIvMX1D_JOuMwr7I_FMl_E.woff2 — 36.9 KiB — 14 ms — font-display: swaphttps://fonts.gstatic.com/s/opensans/v44/memvYaGs126MiZpBA-UvWbX2vVnXBbObj2OVTS-mu0SC55I.woff2memvYaGs126MiZpBA-UvWbX... https://fonts.gstatic.com/s/opensans/v44/memvYaGs126MiZpBA-UvWbX2vVnXBbObj2OVTS-mu0SC55I.woff2 — 42.0 KiB — 22 ms — font-display: swaphttps://fonts.gstatic.com/s/lora/v37/0QIhMX1D_JOuMw_LIftLtfOm8w.woff20QIhMX1D_JOuMw_LIftLtfO... https://fonts.gstatic.com/s/lora/v37/0QIhMX1D_JOuMw_LIftLtfOm8w.woff2 — 39.7 KiB — 24 ms — font-display: swaphttps://fonts.gstatic.com/s/opensans/v44/memvYaGs126MiZpBA-UvWbX2vVnXBbObj2OVTVOmu0SC55K5gw.woff2memvYaGs126MiZpBA-UvWbX... https://fonts.gstatic.com/s/opensans/v44/memvYaGs126MiZpBA-UvWbX2vVnXBbObj2OVTVOmu0SC55K5gw.woff2 — 45.8 KiB — 24 ms — font-display: swap
remixicon.woff2 woff2 swap
Size 162 KB
Load time 50 ms
Start 473 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
0QIvMX1D_JOuMwr7I_FMl_E... woff2 swap
Size 37 KB
Load time 14 ms
Start 473 ms
Risk FOUT — text flashes from fallback to web font
memvYaGs126MiZpBA-UvWbX... woff2 swap
Size 42 KB
Load time 22 ms
Start 475 ms
Risk FOUT — text flashes from fallback to web font
0QIhMX1D_JOuMw_LIftLtfO... woff2 swap
Size 40 KB
Load time 24 ms
Start 476 ms
Risk FOUT — text flashes from fallback to web font
memvYaGs126MiZpBA-UvWbX... woff2 swap
Size 46 KB
Load time 24 ms
Start 477 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 ~81 KB and ~162 ms

A+
JS Bundles
3 scripts, 21 KB unused
PASS
3 scripts, 21 KB unused
Warning::
https://martinfowler.com/jquery-1.11.3.min.js: 21 KB unused (64%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 21 KB
21 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://martinfowler.com/jquery-1.11.3.min.js33 KB21 KB (64%)✓1st
https://cloud.umami.is/script.js3 KB—✓3rd
https://martinfowler.com/mfcom.js2 KB—✓1st

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

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
Network Waterfall
25 requests over 1020ms
INFO
0 ms 500 ms 1.0 s 1.5 s FCP 1.1 s LCP 1.5 shttps://martinfowler.com// https://martinfowler.com/ — 200 — 10.1 KiB — 213 ms — http/1.1https://cloud.umami.is/script.jscloud.umami.is/script.js https://cloud.umami.is/script.js — 200 — 3.2 KiB — 36 ms — h2https://martinfowler.com/home.css/home.css https://martinfowler.com/home.css — 200 — 4.9 KiB — 73 ms — http/1.1https://martinfowler.com/mf-name-white.png/mf-name-white.png https://martinfowler.com/mf-name-white.png — 200 — 7.2 KiB — 72 ms — http/1.1https://martinfowler.com/img/mf-dallas.jpg/img/mf-dallas.jpg https://martinfowler.com/img/mf-dallas.jpg — 200 — 204.2 KiB — 346 ms — http/1.1https://martinfowler.com/photos/131.jpg/photos/131.jpg https://martinfowler.com/photos/131.jpg — 200 — 340.7 KiB — 478 ms — http/1.1https://martinfowler.com/architecture/oscon.png/architecture/oscon.png https://martinfowler.com/architecture/oscon.png — 200 — 172.0 KiB — 402 ms — http/1.1https://martinfowler.com/board-games.png/board-games.png https://martinfowler.com/board-games.png — 200 — 309.8 KiB — 480 ms — http/1.1https://martinfowler.com/jquery-1.11.3.min.js/jquery-1.11.3.min.js https://martinfowler.com/jquery-1.11.3.min.js — 200 — 33.1 KiB — 211 ms — http/1.1https://martinfowler.com/mfcom.js/mfcom.js https://martinfowler.com/mfcom.js — 200 — 2.4 KiB — 147 ms — http/1.1https://fonts.googleapis.com/css?family=Open+Sans:300italic,400italic,300,400,600,700,800fonts.googleapis.com/css?family=Ope... https://fonts.googleapis.com/css?family=Open+Sans:300italic,400italic,300,400,600,700,800 — 200 — 2.2 KiB — 80 ms — h2https://fonts.googleapis.com/css?family=Inconsolata:400,700fonts.googleapis.com/css?family=Inc... https://fonts.googleapis.com/css?family=Inconsolata:400,700 — 200 — 990 B — 75 ms — h2https://fonts.googleapis.com/css?family=Lora:400,400i,700,700ifonts.googleapis.com/css?family=Lor... https://fonts.googleapis.com/css?family=Lora:400,400i,700,700i — 200 — 1.7 KiB — 79 ms — h2https://martinfowler.com/articles/mechanical-sympathy-principles/card.png/articles/mechanical-sympathy-princ... https://martinfowler.com/articles/mechanical-sympathy-principles/card.png — 200 — 237.7 KiB — 333 ms — http/1.1https://martinfowler.com/articles/harness-engineering/card.png/articles/harness-engineering/card.... https://martinfowler.com/articles/harness-engineering/card.png — 200 — 65.5 KiB — 137 ms — http/1.1https://martinfowler.com/banner.png/banner.png https://martinfowler.com/banner.png — 200 — 55.1 KiB — 177 ms — http/1.1https://cdn.jsdelivr.net/npm/remixicon@4.3.0/fonts/remixicon.woff2?t=1590207869815cdn.jsdelivr.net/npm/remixicon@4.3.... https://cdn.jsdelivr.net/npm/remixicon@4.3.0/fonts/remixicon.woff2?t=1590207869815 — 200 — 162.5 KiB — 50 ms — h2https://fonts.gstatic.com/s/lora/v37/0QIvMX1D_JOuMwr7I_FMl_E.woff2fonts.gstatic.com/s/lora/v37/0QIvMX... https://fonts.gstatic.com/s/lora/v37/0QIvMX1D_JOuMwr7I_FMl_E.woff2 — 200 — 36.9 KiB — 14 ms — h3https://fonts.gstatic.com/s/opensans/v44/memvYaGs126MiZpBA-UvWbX2vVnXBbObj2OVTS-mu0SC55I.woff2fonts.gstatic.com/s/opensans/v44/me... https://fonts.gstatic.com/s/opensans/v44/memvYaGs126MiZpBA-UvWbX2vVnXBbObj2OVTS-mu0SC55I.woff2 — 200 — 42.0 KiB — 22 ms — h3https://fonts.gstatic.com/s/lora/v37/0QIhMX1D_JOuMw_LIftLtfOm8w.woff2fonts.gstatic.com/s/lora/v37/0QIhMX... https://fonts.gstatic.com/s/lora/v37/0QIhMX1D_JOuMw_LIftLtfOm8w.woff2 — 200 — 39.7 KiB — 24 ms — h3https://fonts.gstatic.com/s/opensans/v44/memvYaGs126MiZpBA-UvWbX2vVnXBbObj2OVTVOmu0SC55K5gw.woff2fonts.gstatic.com/s/opensans/v44/me... https://fonts.gstatic.com/s/opensans/v44/memvYaGs126MiZpBA-UvWbX2vVnXBbObj2OVTVOmu0SC55K5gw.woff2 — 200 — 45.8 KiB — 24 ms — h3https://martinfowler.com/thoughtworks_white.png/thoughtworks_white.png https://martinfowler.com/thoughtworks_white.png — 200 — 11.4 KiB — 71 ms — http/1.1https://api-gateway.umami.dev/api/sendapi-gateway.umami.dev/api/send https://api-gateway.umami.dev/api/send — 200 — 0 B — 26 ms — h3https://martinfowler.com/favicon.ico/favicon.ico https://martinfowler.com/favicon.ico — 200 — 139.7 KiB — 73 ms — http/1.1https://api-gateway.umami.dev/api/sendapi-gateway.umami.dev/api/send https://api-gateway.umami.dev/api/send — 200 — 1.1 KiB — 215 ms — h3
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
35% of JavaScript execution is third-party
First-party Third-party 76ms · 0KB · $1/mo
Unattributable
Other
Optional
Execution 76ms
Transfer 0 KB
Monthly Cost $1/mo

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.

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