Performance
· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
439 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
771 ms
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
70 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.002
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.17 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.
2.91 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 sFPage Weight BudgetAction3.1 MB transferred, 54 requestsFIX
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
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.
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.
Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).
Source: web.dev font loading
FJS BundlesAction4 scripts, 713 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://ourworldindata.org/assets/owid.mjs | 988 KB | 591 KB (60%) | ✓ | 1st |
| https://www.googletagmanager.com/gtag/js?id=G-RSY8NMC3MT&cx=c>m=4e64h1 | 152 KB | 63 KB (42%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-N2D4V8S | 130 KB | 58 KB (45%) | ✓ | 3rd |
| https://static.cloudflareinsights.com/beacon.min.js | 11 KB | — | ✓ | 3rd |
Consider code splitting or tree shaking to reduce unused code.
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.
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.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
DPage Weight InventoryAction54 resources · 3.1 MB · 713 KB savings availableFIX
~712.5 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 54 resources | 3.1 MiB | ||||||
BImage Optimization30 images, 0 KB saveableREVIEW
BJS Execution Cost889ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| Unattributable | 364ms | 166ms | 0ms | 3rd |
| https://ourworldindata.org/assets/owid.mjs | 215ms | 170ms | 3ms | 1st |
| https://ourworldindata.org/ | 205ms | 5ms | 5ms | 1st |
| https://www.googletagmanager.com/gtag/js?id=G-RSY8NMC3MT&cx=c>m=4e64h1 | 53ms | 44ms | 8ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-N2D4V8S | 52ms | 45ms | 7ms | 3rd |
BHTTP Cachingno-cacheREVIEW
no-cache
| Directive | Value | Meaning |
|---|---|---|
| no-cache | — | Cache but always revalidate first |
A+Third-Party Impact9% third-party, 0 ms blockingPASS
A+Text CompressionAll text resources are compressedPASS
A+Font Loading9 fonts (303 KB)PASS
Web fonts
9
303 KB total
Render-blocking
0
of 9
Dominant font-display
swap
Most common across fonts
Font loading timeline
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+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Network Waterfall54 requests over 1227msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 364ms | 0 KB | — | €4/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 53ms | 152 KB | 42% | €1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 52ms | 130 KB | 45% | €1/mo | Optional |
These scripts may cost more than they're worth
- Unattributable adds 364ms and costs ~€4/month
53% of JavaScript execution time comes from third-party scripts.
Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.
Learn more ▾ ▴
Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.
Source: web.dev / HTTP Archive Web Almanac
Unattributable takes 364ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev