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https://www.cohere.com

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
72
GRADE
C
FIX
4
REVIEW
3
PASS
7
INFO
2

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

Mobile Desktop
27
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
98
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.
92
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.

4.48 s

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

22.56 s

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

3.92 s

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.

13.31 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.

26.62 s

Page Load Progression

532 ms
1.1 s
1.6 s
2.1 s
2.7 s
3.2 s
3.7 s
4.3 s
Checks
16
7 PASS 3 REVIEW 4 FIX
F
Page Weight Budget
Action
4.7 MB transferred, 145 requests
FIX
4.7 MB transferred, 145 requests
Critical::
Page weighs 10.9 MB (4.7 MB transferred)
Warning::
Images are 2.1 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 2.1 MB
Warning::
JavaScript is 1.8 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.8 MB
Info::
Fonts are 424 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 424 KB
Warning::
145 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 0.99 g CO2 per page load
4.7 MB / 2.4 MB budget
4.7 MB transferred
145 requests
0.99 g CO2 per page load
Images 2.1 MiB 45%
JavaScript 1.8 MiB 39%
Fonts 424.4 KiB 9%
Other 116.2 KiB 2%
Other 115.0 KiB 2%
HTML 69.4 KiB 1%
CSS 59.4 KiB 1%
Other 1.6 KiB 0%
Other 767 B 0%
Other 578 B 0%
Other 0 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

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

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

D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (4.7 MiB of 4.7 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
JS Execution Cost
Action
16731ms total JS execution
FIX
16731ms total JS execution
Warning::
https://cohere.com/_next/static/chunks/35a9f203-8f...: 6287ms CPU time
Warning::
https://cohere.com/_next/static/chunks/3372-d43a11...: 3031ms CPU time
Warning::
Unattributable: 1582ms CPU time
Warning::
https://cohere.com/: 1530ms CPU time
Warning::
https://cohere.com/_next/static/chunks/6815-980a79...: 898ms CPU time
Warning::
Third-party scripts: 16731ms (100% of total)

Main Thread Breakdown

Script Evaluation 61% Other 17% Style & Layout 8% Script Parsing & Compilation 7% Garbage Collection 3%
ScriptTotalScriptingParse/CompileParty
https://cohere.com/_next/static/chunks/35a9f203-8f15a8e7798acbe6.js6287ms5937ms58ms3rd
https://cohere.com/_next/static/chunks/3372-d43a11ed3cf32462.js3031ms2616ms35ms3rd
Unattributable1582ms81ms0ms3rd
https://cohere.com/1530ms49ms112ms3rd
https://cohere.com/_next/static/chunks/6815-980a790505f7a80c.js898ms96ms13ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-5W6STPC520ms415ms87ms3rd
https://cdn-cookieyes.com/client_data/72267d03a3814ff1204bd164/banner.js508ms244ms4ms3rd
https://cohere.com/_next/static/chunks/2d1400c4.33880f77071ba18f.js390ms306ms57ms3rd
https://t.contentsquare.net/uxa/9298be563ec16.js383ms190ms71ms3rd
https://www.googletagmanager.com/gtag/js?id=G-S33PXJMLTN&cx=c&gtm=4e6460h1359ms271ms85ms3rd

Showing top 10 of 21 scripts

F
JS Bundles
Action
61 scripts, 918 KB unused
FIX
61 scripts, 918 KB unused
Warning::
https://cohere.com/_next/static/chunks/8043-a2ddd1...: 115 KB unused (59%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cohere.com/_next/static/chunks/35a9f203-8f...: 114 KB unused (95%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://t.contentsquare.net/uxa/9298be563ec16.js: 99 KB unused (78%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-5W6...: 81 KB unused (49%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cohere.com/_next/static/chunks/79a5c8c7-8d...: 76 KB unused (90%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 918 KB
918 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://cohere.com/_next/static/chunks/8043-a2ddd12a50120d22.js197 KB115 KB (59%)✓3rd
https://cohere.com/_next/static/chunks/35a9f203-8f15a8e7798acbe6.js120 KB114 KB (95%)✓3rd
https://t.contentsquare.net/uxa/9298be563ec16.js127 KB99 KB (78%)✓3rd
https://www.googletagmanager.com/gtm.js?id=GTM-5W6STPC167 KB81 KB (49%)✓3rd
https://cohere.com/_next/static/chunks/79a5c8c7-8d2e1a2c5f91247c.js85 KB76 KB (90%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-S33PXJMLTN&cx=c&gtm=4e6460h1169 KB69 KB (41%)✓3rd
https://cohere.com/_next/static/chunks/2d1400c4.33880f77071ba18f.js78 KB46 KB (59%)✓3rd
https://cohere.com/_next/static/chunks/9979-24400beca6c34fe1.js49 KB42 KB (86%)✓3rd
https://cohere.com/_next/static/chunks/4069-0a5c37214518f62c.js57 KB41 KB (72%)✓3rd
https://cohere.com/_next/static/chunks/56ad31fa-0b649efe885326be.js76 KB41 KB (53%)✓3rd

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

B
Image Optimization
53 images, 0 KB saveable
REVIEW
53 images, 0 KB saveable
Info::
All images are well-optimized
53 images 2.1 MB
0 oversized -0 KB
28 legacy format
0 missing dimensions CLS risk
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

B
HTTP Caching
public, max-age=0, must-revalidate
REVIEW
public, max-age=0, must-revalidate
Info::
Cache-Control header is set
Got: public, max-age=0, must-revalidate
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

public, max-age=0, must-revalidate

DirectiveValueMeaning
public—Any cache may store this response
max-age0Cache for 0 seconds
must-revalidate—Must recheck with server after expiry
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
6 fonts (424 KB)
PASS
6 fonts (424 KB)
Info::
6 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

6

424 KB total

Render-blocking

0

of 6

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s 12.0 s 14.0 s 16.0 s 18.0 s 20.0 s 22.0 s FCP 4.5 s LCP 22.6 shttps://cohere.com/_next/static/media/Unica77CohereWeb-Regular.e3763c16.woff2Unica77CohereWeb-Regula... https://cohere.com/_next/static/media/Unica77CohereWeb-Regular.e3763c16.woff2 — 114.5 KiB — 0 ms — font-display: swaphttps://cohere.com/_next/static/media/CohereIcon-Default.c14e50a0.woffCohereIcon-Default.c14e... https://cohere.com/_next/static/media/CohereIcon-Default.c14e50a0.woff — 17.4 KiB — 0 ms — font-display: swaphttps://cohere.com/_next/static/media/CohereText-Regular.870d4a70.woff2CohereText-Regular.870d... https://cohere.com/_next/static/media/CohereText-Regular.870d4a70.woff2 — 34.5 KiB — 0 ms — font-display: swaphttps://cohere.com/_next/static/media/Unica77CohereWeb-Bold.1195007b.woff2Unica77CohereWeb-Bold.1... https://cohere.com/_next/static/media/Unica77CohereWeb-Bold.1195007b.woff2 — 118.7 KiB — 0 ms — font-display: swaphttps://cohere.com/_next/static/media/CohereMono-Regular.d3cdd41a.woff2CohereMono-Regular.d3cd... https://cohere.com/_next/static/media/CohereMono-Regular.d3cdd41a.woff2 — 24.1 KiB — 0 ms — font-display: swaphttps://cohere.com/_next/static/media/Unica77CohereWeb-Medium.45bad867.woff2Unica77CohereWeb-Medium... https://cohere.com/_next/static/media/Unica77CohereWeb-Medium.45bad867.woff2 — 115.2 KiB — 0 ms — font-display: swap
Unica77CohereWeb-Regula... woff2 swap
Size 115 KB
Load time 0 ms
Start 0 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
CohereIcon-Default.c14e... woff swap
Size 17 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
CohereText-Regular.870d... woff2 swap
Size 34 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Unica77CohereWeb-Bold.1... woff2 swap
Size 119 KB
Load time 0 ms
Start 0 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
CohereMono-Regular.d3cd... woff2 swap
Size 24 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Unica77CohereWeb-Medium... woff2 swap
Size 115 KB
Load time 0 ms
Start 0 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
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 ~179 KB and ~358 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
20 hints, 0 missing preconnects
PASS
20 hints, 0 missing preconnects
Info::
Page uses 20 resource hint(s)

Current Resource Hints

preconnect
—
preload
+10
20
dns-prefetch
—
prefetch
—

20 resource hints configured

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
Network Waterfall
145 requests over 0ms
INFO

Performance analysis not available for this result.

Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100% of JavaScript execution is third-party
First-party Third-party 16731ms · 1535KB · €268/mo
cohere.com
Other
Costly
Execution 6287ms
Transfer 120 KB
Unused 95%
Monthly Cost €101/mo
cohere.com
Other
Costly
Execution 3031ms
Transfer 51 KB
Unused 46%
Monthly Cost €48/mo
Unattributable
Other
Costly
Execution 1582ms
Transfer 0 KB
Monthly Cost €25/mo
cohere.com
Other
Costly
Execution 1530ms
Transfer 69 KB
Monthly Cost €24/mo
cohere.com
Other
Costly
Execution 898ms
Transfer 26 KB
Unused 84%
Monthly Cost €14/mo
Google Tag Manager
Tag Manager
Costly
Execution 520ms
Transfer 167 KB
Unused 49%
Monthly Cost €8/mo
cdn-cookieyes.com
Other
Costly
Execution 508ms
Transfer 8 KB
Monthly Cost €8/mo
cohere.com
Other
Costly
Execution 390ms
Transfer 78 KB
Unused 59%
Monthly Cost €6/mo
t.contentsquare.net
Other
Costly
Execution 383ms
Transfer 127 KB
Unused 78%
Monthly Cost €6/mo
Google Tag Manager
Tag Manager
Costly
Execution 359ms
Transfer 169 KB
Unused 41%
Monthly Cost €6/mo
cohere.com
Other
Costly
Execution 311ms
Transfer 54 KB
Monthly Cost €5/mo
cohere.com
Other
Costly
Execution 307ms
Transfer 21 KB
Monthly Cost €5/mo
cohere.com
Other
Optional
Execution 118ms
Transfer 197 KB
Unused 59%
Monthly Cost €2/mo
cohere.com
Other
Optional
Execution 100ms
Transfer 158 KB
Monthly Cost €2/mo
cohere.com
Other
Optional
Execution 68ms
Transfer 6 KB
Monthly Cost €1/mo
cohere.com
Other
Optional
Execution 68ms
Transfer 76 KB
Unused 53%
Monthly Cost €1/mo
cohere.com
Other
Optional
Execution 57ms
Transfer 28 KB
Unused 94%
Monthly Cost €1/mo
cdn-cookieyes.com
Other
Optional
Execution 54ms
Transfer 9 KB
Monthly Cost €1/mo
cohere.com
Other
Optional
Execution 54ms
Transfer 85 KB
Unused 90%
Monthly Cost €1/mo
cohere.com
Other
Optional
Execution 54ms
Transfer 26 KB
Unused 83%
Monthly Cost €1/mo
cohere.com
Other
Optional
Execution 50ms
Transfer 59 KB
Unused 52%
Monthly Cost €1/mo

These scripts may cost more than they're worth

  • cohere.com adds 6287ms and costs ~€101/month
  • cohere.com adds 3031ms and costs ~€48/month
  • Unattributable adds 1582ms and costs ~€25/month
  • cohere.com adds 1530ms and costs ~€24/month
  • cohere.com adds 898ms and costs ~€14/month
  • Google Tag Manager adds 520ms and costs ~€8/month
  • cdn-cookieyes.com adds 508ms and costs ~€8/month
  • cohere.com adds 390ms and costs ~€6/month
  • t.contentsquare.net adds 383ms and costs ~€6/month
  • Google Tag Manager adds 359ms and costs ~€6/month
  • cohere.com adds 311ms and costs ~€5/month
  • cohere.com adds 307ms and costs ~€5/month

100% 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

cohere.com takes 6287ms 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

95% of cohere.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

cohere.com takes 3031ms 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

Unattributable takes 1582ms 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

cohere.com takes 1530ms 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

cohere.com takes 898ms 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

84% of cohere.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

Google Tag Manager takes 520ms 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

cdn-cookieyes.com takes 508ms 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

cohere.com takes 390ms 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

59% of cohere.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

t.contentsquare.net takes 383ms 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

78% of t.contentsquare.net'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

Google Tag Manager takes 359ms 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

cohere.com takes 311ms 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

cohere.com takes 307ms 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

59% of cohere.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

53% of cohere.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

94% of cohere.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

90% of cohere.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

83% of cohere.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

52% of cohere.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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