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https://peerj.com

Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
71
GRADE
C
FIX
4
REVIEW
3
PASS
6
INFO
2

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

Mobile Desktop
72
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
100
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.
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.

1.10 s

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

2.94 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

122 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.101

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

2.29 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.

3.11 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
6 PASS 3 REVIEW 4 FIX
F
Page Weight Budget
Action
2.8 MB transferred, 60 requests
FIX
2.8 MB transferred, 60 requests
Warning::
Page weighs 7.0 MB (2.8 MB transferred)
Warning::
JavaScript is 1.2 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.2 MB
Info::
Fonts are 433 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 433 KB
Info::
60 HTTP requests
Info::
Estimated 0.60 g CO2 per page load
2.8 MB / 2.4 MB budget
2.8 MB transferred
60 requests
0.60 g CO2 per page load
JavaScript 1.2 MiB 43%
Images 991.1 KiB 34%
Fonts 433.4 KiB 15%
CSS 187.9 KiB 6%
Other 31.9 KiB 1%
Other 12.9 KiB 0%
HTML 10.1 KiB 0%
Other 5.9 KiB 0%
Other 1.8 KiB 0%
0 2.4 MB 4.9 MB
Over budget

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Why this matters

JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.

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

D
Third-Party Impact
Action
91% third-party, 0 ms blocking
FIX
91% third-party, 0 ms blocking
Warning::
Third-party code accounts for 91% of page weight (2.6 MiB of 2.8 MiB)
Info::
Third-party blocking time is low (0 ms)
91%
First-party Third-party
F
JS Bundles
Action
25 scripts, 683 KB unused
FIX
25 scripts, 683 KB unused
Warning::
https://cdn.peerj.com/cb040aa/webpack/peerj-app.6c...: 468 KB unused (76%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn.peerj.com/cb040aa/webpack/330.a5145fec...: 64 KB unused (49%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://peerj.com/js/8d39319-582a9a0.js: 50 KB unused (67%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://peerj.com/js/8d39319-582a9a0.js: unminified — 33 KB could be saved
Warning::
https://peerj.com/js/f67db00-8264f27.js: 46 KB unused (49%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://peerj.com/js/f67db00-8264f27.js: unminified — 45 KB could be saved
Warning::
https://transcend-cdn.com/cm/ef49a3f1-d8c1-47d6-88...: 28 KB unused (34%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 683 KB
683 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://cdn.peerj.com/cb040aa/webpack/peerj-app.6cc34b02.js623 KB468 KB (76%)✓3rd
https://cdn.peerj.com/cb040aa/webpack/330.a5145fec.js131 KB64 KB (49%)✓3rd
https://peerj.com/js/8d39319-582a9a0.js75 KB50 KB (67%)✗1st
https://peerj.com/js/f67db00-8264f27.js93 KB46 KB (49%)✗1st
https://transcend-cdn.com/cm/ef49a3f1-d8c1-47d6-88fc-50e41130631f/tcf/ui.js85 KB28 KB (34%)✓3rd
https://cdn.mxpnl.com/libs/mixpanel-2-latest.min.js32 KB26 KB (83%)✓3rd
https://pushpad.xyz/pushpad.js6 KB—✓3rd
https://cdn.peerj.com/cb040aa/webpack/1024.3817f300.js5 KB—✓3rd
https://cdn.peerj.com/cb040aa/webpack/runtime.128817d8.js17 KB—✓3rd
https://peerj.com/js/05779bd-a411a7a.js6 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

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

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

F
Page Weight Inventory
Action
60 resources · 2.8 MB · 683 KB savings available
FIX
60 resources · 2.8 MB · 683 KB savings available
Warning::
Page weight 1.8 MB over 1MB target
Got: 2.8 MB Expected: ≤ 1 MB
Info::
~683 KB of savings available
Warning::
46 third-party resources (91% of weight)
Info::
4 resources over 200KB
60 resources · 2.8 MiB · 46 third-party 1.8 MiB over 1MB target
JavaScript 43% · 1.2 MiB
Image 34% · 997.0 KiB
Font 15% · 433.4 KiB
CSS 6% · 187.9 KiB
Other 2% · 46.5 KiB
Document 0% · 10.1 KiB

~683.3 KiB of savings available

Remove unused JavaScript: 683.3 KiB
C
Image Optimization
Action
5 images, 0 KB saveable
REVIEW
5 images, 0 KB saveable
Warning::
https://peerj.com/assets/images/landing-pages/peer... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://s3.amazonaws.com/static.peerj.com/images/j... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
5 images 991 KB
0 oversized -0 KB
5 legacy format
2 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

B
JS Execution Cost
860ms total JS execution
REVIEW
860ms total JS execution
Info::
https://cdn.peerj.com/cb040aa/webpack/peerj-app.6c...: 243ms CPU time
Info::
https://cdn.peerj.com/cb040aa/webpack/1042.5ccb850...: 144ms CPU time
Info::
Unattributable: 117ms CPU time
Info::
https://cdn.peerj.com/cb040aa/webpack/1009.ce1d475...: 87ms CPU time
Info::
https://cdn.peerj.com/cb040aa/webpack/398.8481fb5e...: 79ms CPU time
Warning::
Third-party scripts: 792ms (92% of total)

Main Thread Breakdown

Script Evaluation 57% Other 14% Style & Layout 12% Script Parsing & Compilation 8% Garbage Collection 4%
ScriptTotalScriptingParse/CompileParty
https://cdn.peerj.com/cb040aa/webpack/peerj-app.6cc34b02.js243ms164ms43ms3rd
https://cdn.peerj.com/cb040aa/webpack/1042.5ccb8502.js144ms106ms0ms3rd
Unattributable117ms28ms0ms3rd
https://cdn.peerj.com/cb040aa/webpack/1009.ce1d475f.js87ms72ms2ms3rd
https://cdn.peerj.com/cb040aa/webpack/398.8481fb5e.js79ms50ms0ms3rd
https://cdn.peerj.com/cb040aa/webpack/330.a5145fec.js70ms29ms8ms3rd
https://peerj.com/69ms10ms1ms1st
https://transcend-cdn.com/cm/ef49a3f1-d8c1-47d6-88fc-50e41130631f/airgap.js52ms46ms5ms3rd
B
HTTP Caching
max-age=0, must-revalidate, proxy-revalidate, public, s-maxage=600
REVIEW
max-age=0, must-revalidate, proxy-revalidate, public, s-maxage=600
Info::
Cache-Control header is set
Got: max-age=0, must-revalidate, proxy-revalidate, public, s-maxage=600
Info::
CDN TTL: 10 minutes (s-maxage=600)
Info::
Last-Modified header present
Cache-Control

max-age=0, must-revalidate, proxy-revalidate, public, s-maxage=600

DirectiveValueMeaning
max-age0Cache for 0 seconds
must-revalidate—Must recheck with server after expiry
proxy-revalidate—
public—Any cache may store this response
s-maxage600CDN caches for 10 minutes
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+
Font Loading
3 fonts (433 KB)
PASS
3 fonts (433 KB)
Info::
3 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

3

433 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 1.0 s 2.0 s 3.0 s FCP 1.1 s LCP 2.9 shttps://cdn.peerj.com/cb040aa/webpack/fonts/materialdesignicons-webfont.bc2c1f6a.woff2materialdesignicons-web... https://cdn.peerj.com/cb040aa/webpack/fonts/materialdesignicons-webfont.bc2c1f6a.woff2 — 284.2 KiB — 104 ms — font-display: swaphttps://fonts.gstatic.com/s/inter/v20/UcCo3FwrK3iLTcviYwYZ8UA3.woff2UcCo3FwrK3iLTcviYwYZ8UA... https://fonts.gstatic.com/s/inter/v20/UcCo3FwrK3iLTcviYwYZ8UA3.woff2 — 71.3 KiB — 86 ms — font-display: swaphttps://fonts.gstatic.com/s/inter/v20/UcCm3FwrK3iLTcvnUwQT9mI1F54.woff2UcCm3FwrK3iLTcvnUwQT9mI... https://fonts.gstatic.com/s/inter/v20/UcCm3FwrK3iLTcvnUwQT9mI1F54.woff2 — 77.9 KiB — 87 ms — font-display: swap
materialdesignicons-web... woff2 swap
Size 284 KB
Load time 104 ms
Start 765 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
UcCo3FwrK3iLTcviYwYZ8UA... woff2 swap
Size 71 KB
Load time 86 ms
Start 1.3 s
Risk FOUT — text flashes from fallback to web font
UcCm3FwrK3iLTcvnUwQT9mI... woff2 swap
Size 78 KB
Load time 87 ms
Start 1.3 s
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 ~142 KB and ~284 ms

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+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

Network Waterfall
60 requests over 1918ms
INFO
0 ms 1.0 s 2.0 s 3.0 s FCP 1.1 s LCP 2.9 shttps://peerj.com// https://peerj.com/ — 200 — 10.1 KiB — 477 ms — h2https://peerj.com/css/01fda25-aa54668.css/css/01fda25-aa54668.css https://peerj.com/css/01fda25-aa54668.css — 200 — 44.3 KiB — 30 ms — h2https://cdn.peerj.com/cb040aa/webpack/330.3c2c95ca.csscdn.peerj.com/cb040aa/webpack/330.3... https://cdn.peerj.com/cb040aa/webpack/330.3c2c95ca.css — 200 — 45.5 KiB — 79 ms — h2https://cdn.peerj.com/cb040aa/webpack/peerj-app.8ae05dc6.csscdn.peerj.com/cb040aa/webpack/peerj... https://cdn.peerj.com/cb040aa/webpack/peerj-app.8ae05dc6.css — 200 — 79.3 KiB — 93 ms — h2https://peerj.com/js/f67db00-8264f27.js/js/f67db00-8264f27.js https://peerj.com/js/f67db00-8264f27.js — 200 — 93.4 KiB — 64 ms — h2https://peerj.com/assets/js/polyfills/includes.js/assets/js/polyfills/includes.js https://peerj.com/assets/js/polyfills/includes.js — 200 — 383 B — 64 ms — h2https://peerj.com/assets/js/polyfills/startsWith.js/assets/js/polyfills/startsWith.js https://peerj.com/assets/js/polyfills/startsWith.js — 200 — 373 B — 63 ms — h2https://transcend-cdn.com/cm/ef49a3f1-d8c1-47d6-88fc-50e41130631f/airgap.jstranscend-cdn.com/cm/ef49a3f1-d8c1-... https://transcend-cdn.com/cm/ef49a3f1-d8c1-47d6-88fc-50e41130631f/airgap.js — 200 — 77.7 KiB — 115 ms — h3https://peerj.com/js/8d39319-582a9a0.js/js/8d39319-582a9a0.js https://peerj.com/js/8d39319-582a9a0.js — 200 — 74.9 KiB — 65 ms — h2https://peerj.com/js/05779bd-a411a7a.js/js/05779bd-a411a7a.js https://peerj.com/js/05779bd-a411a7a.js — 200 — 5.8 KiB — 64 ms — h2https://cdn.peerj.com/cb040aa/webpack/runtime.128817d8.jscdn.peerj.com/cb040aa/webpack/runti... https://cdn.peerj.com/cb040aa/webpack/runtime.128817d8.js — 200 — 16.9 KiB — 93 ms — h2https://cdn.peerj.com/cb040aa/webpack/198.0671974e.jscdn.peerj.com/cb040aa/webpack/198.0... https://cdn.peerj.com/cb040aa/webpack/198.0671974e.js — 200 — 7.4 KiB — 57 ms — h2https://cdn.peerj.com/cb040aa/webpack/330.a5145fec.jscdn.peerj.com/cb040aa/webpack/330.a... https://cdn.peerj.com/cb040aa/webpack/330.a5145fec.js — 200 — 131.1 KiB — 125 ms — h2https://cdn.peerj.com/cb040aa/webpack/peerj-app.6cc34b02.jscdn.peerj.com/cb040aa/webpack/peerj... https://cdn.peerj.com/cb040aa/webpack/peerj-app.6cc34b02.js — 200 — 623.1 KiB — 131 ms — h2https://fonts.googleapis.com/css2?family=Inter:ital,opsz,wght@0,14..32,100..900;1,14..32,100..900&display=swapfonts.googleapis.com/css2?family=In... https://fonts.googleapis.com/css2?family=Inter:ital,opsz,wght@0,14..32,100..900;1,14..32,100..900&display=swap — 200 — 1.1 KiB — 85 ms — h2https://peerj.com/assets/js/mixpanel.js/assets/js/mixpanel.js https://peerj.com/assets/js/mixpanel.js — 200 — 1.0 KiB — 26 ms — h2https://transcend-cdn.com/cm/ef49a3f1-d8c1-47d6-88fc-50e41130631f/policies/GDPR.jsontranscend-cdn.com/cm/ef49a3f1-d8c1-... https://transcend-cdn.com/cm/ef49a3f1-d8c1-47d6-88fc-50e41130631f/policies/GDPR.json — 200 — 6.5 KiB — 49 ms — h3https://transcend-cdn.com/cm/ef49a3f1-d8c1-47d6-88fc-50e41130631f/tcf/ui.jstranscend-cdn.com/cm/ef49a3f1-d8c1-... https://transcend-cdn.com/cm/ef49a3f1-d8c1-47d6-88fc-50e41130631f/tcf/ui.js — 200 — 84.7 KiB — 78 ms — h3https://peerj.com/x-country/?_=1776899381668/x-country/?_=1776899381668 https://peerj.com/x-country/?_=1776899381668 — 200 — 337 B — 149 ms — h2https://pushpad.xyz/pushpad.jspushpad.xyz/pushpad.js https://pushpad.xyz/pushpad.js — 200 — 5.7 KiB — 66 ms — h2https://cdn.peerj.com/cb040aa/webpack/fonts/materialdesignicons-webfont.bc2c1f6a.woff2cdn.peerj.com/cb040aa/webpack/fonts... https://cdn.peerj.com/cb040aa/webpack/fonts/materialdesignicons-webfont.bc2c1f6a.woff2 — 200 — 284.2 KiB — 104 ms — h2https://d2pdyyx74uypu5.cloudfront.net/images/favicon/peerj/manifest.jsond2pdyyx74uypu5.cloudfront.net/image... https://d2pdyyx74uypu5.cloudfront.net/images/favicon/peerj/manifest.json — 200 — 1.8 KiB — 55 ms — http/1.1https://cdn.peerj.com/cb040aa/webpack/192.7954e175.csscdn.peerj.com/cb040aa/webpack/192.7... https://cdn.peerj.com/cb040aa/webpack/192.7954e175.css — 200 — 2.2 KiB — 19 ms — h2https://cdn.peerj.com/cb040aa/webpack/192.a4f13c83.jscdn.peerj.com/cb040aa/webpack/192.a... https://cdn.peerj.com/cb040aa/webpack/192.a4f13c83.js — 200 — 16.1 KiB — 19 ms — h2https://cdn.peerj.com/cb040aa/webpack/230.be4f9cb3.csscdn.peerj.com/cb040aa/webpack/230.b... https://cdn.peerj.com/cb040aa/webpack/230.be4f9cb3.css — 200 — 896 B — 20 ms — h2https://cdn.peerj.com/cb040aa/webpack/230.b4278b97.jscdn.peerj.com/cb040aa/webpack/230.b... https://cdn.peerj.com/cb040aa/webpack/230.b4278b97.js — 200 — 9.3 KiB — 21 ms — h2https://cdn.peerj.com/cb040aa/webpack/1024.3b00d89e.csscdn.peerj.com/cb040aa/webpack/1024.... https://cdn.peerj.com/cb040aa/webpack/1024.3b00d89e.css — 200 — 1.0 KiB — 20 ms — h2https://cdn.peerj.com/cb040aa/webpack/1024.3817f300.jscdn.peerj.com/cb040aa/webpack/1024.... https://cdn.peerj.com/cb040aa/webpack/1024.3817f300.js — 200 — 4.8 KiB — 21 ms — h2https://cdn.peerj.com/cb040aa/webpack/1040.251e73b2.csscdn.peerj.com/cb040aa/webpack/1040.... https://cdn.peerj.com/cb040aa/webpack/1040.251e73b2.css — 200 — 406 B — 22 ms — h2https://cdn.peerj.com/cb040aa/webpack/1040.6aab3c12.jscdn.peerj.com/cb040aa/webpack/1040.... https://cdn.peerj.com/cb040aa/webpack/1040.6aab3c12.js — 200 — 2.0 KiB — 22 ms — h2
0 ms 1.0 s 2.0 s 3.0 s FCP 1.1 s LCP 2.9 shttps://peerj.com// https://peerj.com/ — 200 — 10.1 KiB — 477 ms — h2https://peerj.com/css/01fda25-aa54668.css/css/01fda25-aa54668.css https://peerj.com/css/01fda25-aa54668.css — 200 — 44.3 KiB — 30 ms — h2https://cdn.peerj.com/cb040aa/webpack/330.3c2c95ca.csscdn.peerj.com/cb040aa/webpack/330.3... https://cdn.peerj.com/cb040aa/webpack/330.3c2c95ca.css — 200 — 45.5 KiB — 79 ms — h2https://cdn.peerj.com/cb040aa/webpack/peerj-app.8ae05dc6.csscdn.peerj.com/cb040aa/webpack/peerj... https://cdn.peerj.com/cb040aa/webpack/peerj-app.8ae05dc6.css — 200 — 79.3 KiB — 93 ms — h2https://peerj.com/js/f67db00-8264f27.js/js/f67db00-8264f27.js https://peerj.com/js/f67db00-8264f27.js — 200 — 93.4 KiB — 64 ms — h2https://peerj.com/assets/js/polyfills/includes.js/assets/js/polyfills/includes.js https://peerj.com/assets/js/polyfills/includes.js — 200 — 383 B — 64 ms — h2https://peerj.com/assets/js/polyfills/startsWith.js/assets/js/polyfills/startsWith.js https://peerj.com/assets/js/polyfills/startsWith.js — 200 — 373 B — 63 ms — h2https://transcend-cdn.com/cm/ef49a3f1-d8c1-47d6-88fc-50e41130631f/airgap.jstranscend-cdn.com/cm/ef49a3f1-d8c1-... https://transcend-cdn.com/cm/ef49a3f1-d8c1-47d6-88fc-50e41130631f/airgap.js — 200 — 77.7 KiB — 115 ms — h3https://peerj.com/js/8d39319-582a9a0.js/js/8d39319-582a9a0.js https://peerj.com/js/8d39319-582a9a0.js — 200 — 74.9 KiB — 65 ms — h2https://peerj.com/js/05779bd-a411a7a.js/js/05779bd-a411a7a.js https://peerj.com/js/05779bd-a411a7a.js — 200 — 5.8 KiB — 64 ms — h2https://cdn.peerj.com/cb040aa/webpack/runtime.128817d8.jscdn.peerj.com/cb040aa/webpack/runti... https://cdn.peerj.com/cb040aa/webpack/runtime.128817d8.js — 200 — 16.9 KiB — 93 ms — h2https://cdn.peerj.com/cb040aa/webpack/198.0671974e.jscdn.peerj.com/cb040aa/webpack/198.0... https://cdn.peerj.com/cb040aa/webpack/198.0671974e.js — 200 — 7.4 KiB — 57 ms — h2https://cdn.peerj.com/cb040aa/webpack/330.a5145fec.jscdn.peerj.com/cb040aa/webpack/330.a... https://cdn.peerj.com/cb040aa/webpack/330.a5145fec.js — 200 — 131.1 KiB — 125 ms — h2https://cdn.peerj.com/cb040aa/webpack/peerj-app.6cc34b02.jscdn.peerj.com/cb040aa/webpack/peerj... https://cdn.peerj.com/cb040aa/webpack/peerj-app.6cc34b02.js — 200 — 623.1 KiB — 131 ms — h2https://fonts.googleapis.com/css2?family=Inter:ital,opsz,wght@0,14..32,100..900;1,14..32,100..900&display=swapfonts.googleapis.com/css2?family=In... https://fonts.googleapis.com/css2?family=Inter:ital,opsz,wght@0,14..32,100..900;1,14..32,100..900&display=swap — 200 — 1.1 KiB — 85 ms — h2https://peerj.com/assets/js/mixpanel.js/assets/js/mixpanel.js https://peerj.com/assets/js/mixpanel.js — 200 — 1.0 KiB — 26 ms — h2https://transcend-cdn.com/cm/ef49a3f1-d8c1-47d6-88fc-50e41130631f/policies/GDPR.jsontranscend-cdn.com/cm/ef49a3f1-d8c1-... https://transcend-cdn.com/cm/ef49a3f1-d8c1-47d6-88fc-50e41130631f/policies/GDPR.json — 200 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HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
92% of JavaScript execution is third-party
First-party Third-party 792ms · 864KB · €9/mo
cdn.peerj.com
Other
Costly
Execution 243ms
Transfer 623 KB
Unused 76%
Monthly Cost €3/mo
cdn.peerj.com
Other
Optional
Execution 144ms
Transfer 2 KB
Monthly Cost €2/mo
Unattributable
Other
Optional
Execution 117ms
Transfer 0 KB
Monthly Cost €1/mo
cdn.peerj.com
Other
Optional
Execution 87ms
Transfer 24 KB
Monthly Cost €1/mo
cdn.peerj.com
Other
Optional
Execution 79ms
Transfer 6 KB
Monthly Cost €1/mo
cdn.peerj.com
Other
Optional
Execution 70ms
Transfer 131 KB
Unused 49%
Monthly Cost €1/mo
transcend-cdn.com
Other
Optional
Execution 52ms
Transfer 78 KB
Monthly Cost €1/mo

These scripts may cost more than they're worth

  • cdn.peerj.com adds 243ms and costs ~€3/month

92% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

cdn.peerj.com takes 243ms 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

76% of cdn.peerj.com's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

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.

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