https://sidekicks.co.uk
Performance
· 28 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.SCORE
85
GRADE
B
FIX
3
REVIEW
5
PASS
16
INFO
4
Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
54
97
96
92
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
5.72 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
16.60 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
213 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.069
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
7.55 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.
17.05 s
Page Load Progression
Checks
2816 PASS 5 REVIEW 3 FIX
FPage Weight BudgetAction3.9 MB transferred, 374 requestsFIX
Page Weight Budget
Action3.9 MB transferred, 374 requests
3.9 MB transferred, 374 requests
Critical::
Page weighs 7.7 MB (3.9 MB transferred)
Warning::
Images are 1.8 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 1.8 MB
Warning::
JavaScript is 1.1 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.1 MB
Warning::
374 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 0.82 g CO2 per page load
3.9 MB transferred
374 requests
0.82 g CO2 per page load
Images 1.8 MiB 47%
JavaScript 1.1 MiB 27%
Other 732.3 KiB 18%
Fonts 163.7 KiB 4%
HTML 111.8 KiB 3%
Other 20.3 KiB 1%
CSS 20.0 KiB 0%
Other 6.9 KiB 0%
Other 1.6 KiB 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
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
FJS Execution CostAction5105ms total JS executionFIX
JS Execution Cost
Action5105ms total JS execution
5105ms total JS execution
Warning::
Unattributable: 1553ms CPU time
Warning::
https://sidekicks.co.uk/: 924ms CPU time
Warning::
https://sidekicks.co.uk/cdn/shop/t/96/assets/libs....: 655ms CPU time
Warning::
https://sidekicks.co.uk/cdn/wpm/b264bf420w2e1681ca...: 473ms CPU time
Warning::
https://sidekicks.co.uk/cdn/shopifycloud/storefron...: 255ms CPU time
Info::
Third-party scripts: 514ms (10% of total)
Main Thread Breakdown
Script Evaluation 40% Other 37% Style & Layout 11% Script Parsing & Compilation 5% Parse HTML & CSS 4% Rendering 4%
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| Unattributable | 1553ms | 47ms | 0ms | 1st |
| https://sidekicks.co.uk/ | 924ms | 170ms | 42ms | 1st |
| https://sidekicks.co.uk/cdn/shop/t/96/assets/libs.js?v=67587959726433910401779293312 | 655ms | 134ms | 12ms | 1st |
| https://sidekicks.co.uk/cdn/wpm/b264bf420w2e1681cap8d55857fm7d879f9cm.js | 473ms | 406ms | 24ms | 1st |
| https://sidekicks.co.uk/cdn/shopifycloud/storefront/assets/storefront/remote_product_tracking-91d95044.js | 255ms | 40ms | 3ms | 1st |
| https://sidekicks.co.uk/cdn/s/trekkie.storefront.387430da5919a2f9b410f0ffaf5b70216a61abfb.min.js | 193ms | 136ms | 12ms | 1st |
| https://sidekicks.co.uk/cdn/shopifycloud/perf-kit/shopify-perf-kit-3.11.0.min.js | 143ms | 130ms | 8ms | 1st |
| https://utt.impactcdn.com/A6309462-95ab-4fbd-a04e-da01bbab4f471.js | 119ms | 106ms | 6ms | 3rd |
| https://sidekicks.co.uk/cdn/shop/t/96/assets/global.js?v=156420388719564633641779293312 | 97ms | 18ms | 3ms | 1st |
| https://d2wy8f7a9ursnm.cloudfront.net/v5/bugsnag.min.js | 90ms | 69ms | 9ms | 3rd |
Showing top 10 of 20 scripts
FHTTP CachingActionNo cache headersFIX
HTTP Caching
ActionNo cache headers
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
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BImage Optimization121 images, 0 KB saveableREVIEW
Image Optimization
121 images, 0 KB saveable
121 images, 0 KB saveable
Info::
All images are well-optimized
121 images 1.8 MB
0 oversized -0 KB
4 legacy format
0 missing dimensions CLS risk
BJS Bundles177 scripts, 88 KB unusedREVIEW
JS Bundles
177 scripts, 88 KB unused
177 scripts, 88 KB unused
Warning::
https://sidekicks.co.uk/cdn/wpm/b264bf420w2e1681ca...: 42 KB unused (50%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://js.smile.io/v1/vendor-core-e53549e6c38a352...: 25 KB unused (58%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://js.smile.io/v1/src_smile-ui_app_containers...: 21 KB unused (96%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 88 KB
88 KB unused JavaScript
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://sidekicks.co.uk/cdn/wpm/b264bf420w2e1681cap8d55857fm7d879f9cm.js | 85 KB | 42 KB (50%) | ✓ | 1st |
| https://js.smile.io/v1/vendor-core-e53549e6c38a352bd8f6.js | 44 KB | 25 KB (58%) | ✓ | 3rd |
| https://js.smile.io/v1/src_smile-ui_app_containers_Panel_PanelView_tsx-7a00e99becd2c7fd44ac.js | 22 KB | 21 KB (96%) | ✓ | 3rd |
| https://sidekicks.co.uk/checkouts/internal/preloads.js?locale=en-FR&default_configuration_id=1036943661 | 4 KB | — | ✓ | 1st |
| https://shop.app/checkouts/internal/preloads.js?locale=en-FR&default_configuration_id=1036943661&shop_id=67221061933 | 0 KB | — | ✓ | 3rd |
| https://cdn.shopify.com/shopifycloud/shop-js/modules/v2/loader.init-shop-cart-sync.en.esm.js | 1 KB | — | ✓ | 3rd |
| https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js | 0 KB | — | ✓ | 3rd |
| https://cdn.jsdelivr.net/npm/slick-carousel@1.8.1/slick/slick.min.js | 0 KB | — | ✓ | 3rd |
| https://cdn.shopify.com/extensions/01a18139-0b3b-7c7a-aab2-59f29fa5eae6/back-in-stock-74/assets/preorder-product-page-updater.js | 4 KB | — | ✓ | 3rd |
| https://cdn.shopify.com/storefront/standard-actions.js | 5 KB | — | ✓ | 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
BMain HTML Cache-ControlNo Cache-Control header on main HTML responseREVIEW
Main HTML Cache-Control
No Cache-Control header on main HTML response
No Cache-Control header on main HTML response
Info::
Main HTML response has no Cache-Control header
Without an explicit Cache-Control, browsers fall back to heuristic caching (~10% of Last-Modified age). Set `Cache-Control: no-cache` or `max-age=300` for HTML to control freshness explicitly -- prevents stale auth state and SPA shell drift.
CPage Weight InventoryAction374 resources · 3.9 MB · 88 KB savings availableREVIEW
Page Weight Inventory
Action374 resources · 3.9 MB · 88 KB savings available
374 resources · 3.9 MB · 88 KB savings available
Warning::
Page weight 3.9 MB exceeds 1 MB target by 2.9 MB
Got: 3.9 MB Expected: ≤ 1 MB
Info::
~88 KB of savings available
Info::
111 third-party resources (18% of weight)
374 resources · 3.9 MiB · 111 third-party 2.9 MiB over 1MB target
Image 47% · 1.8 MiB
JavaScript 45% · 1.8 MiB
Font 4% · 163.7 KiB
Document 3% · 116.9 KiB
Other 1% · 28.3 KiB
CSS 0% · 20.0 KiB
~87.9 KiB of savings available
Remove unused JavaScript: 87.9 KiB
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 374 resources | 3.9 MiB | ||||||
BJavaScript Blocking2 JS blocking issue(s) detectedREVIEW
JavaScript Blocking
2 JS blocking issue(s) detected
2 JS blocking issue(s) detected
Warning::
4 render-blocking <script src> tag(s) without async/defer
Each `<script src=...>` without `async`, `defer`, or `type="module"` blocks HTML parsing while the browser fetches and executes it. The block lasts the entire round-trip + execution time -- on slow networks this translates directly into LCP delay. Add `defer` (executes after parse, in source order) for scripts that interact with the DOM, or `async` (executes whenever ready) for analytics / independent scripts. Module scripts (`type="module"`) are deferred by default.
Warning::
Total JS execution time is 5.1 s -- over the 3.5s budget
Total JavaScript execution (parse + compile + run) across all scripts exceeds 3.5 seconds. On low-end devices that becomes 7-15+ seconds and shows up directly in TBT and INP. Reduce by: tree-shaking unused dependencies, code-splitting (dynamic `import()`), removing or deferring third-party tracking, and replacing heavy frameworks where they're not needed.
A+Third-Party Impact18% third-party, 0 ms blockingPASS
Third-Party Impact
18% third-party, 0 ms blocking
18% third-party, 0 ms blocking
Info::
Third-party code accounts for 18% of page weight (706.4 KiB of 3.9 MiB)
Info::
Third-party blocking time is low (0 ms)
82%
18%
First-party Third-party
A+Text CompressionAll text resources are compressedPASS
Text Compression
All text resources are compressed
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+Font Loading4 fonts (164 KB)PASS
Font Loading
4 fonts (164 KB)
4 fonts (164 KB)
Info::
4 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
4
164 KB total
Render-blocking
0
of 4
Dominant font-display
swap
Most common across fonts
Font loading timeline
Transfer FOIT (block) FOUT (swap)
inter_n5.d7101d5e168594... woff2 swap
Size 40 KB
Load time 55 ms
Start 947 ms
Risk FOUT — text flashes from fallback to web font
archivo_n5.272841b6d6b8... woff2 swap
Size 46 KB
Load time 48 ms
Start 947 ms
Risk FOUT — text flashes from fallback to web font
inter_n7.02711e6b374660... woff2 swap
Size 39 KB
Load time 61 ms
Start 1.3 s
Risk FOUT — text flashes from fallback to web font
inter_n4.b2a3f24c19b4de... woff2 swap
Size 39 KB
Load time 30 ms
Start 1.9 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)
A+Resource CachingAll resources properly cachedPASS
Resource Caching
All resources properly cached
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+Critical Rendering PathNo render-blocking resourcesPASS
Critical Rendering Path
No render-blocking resources
No render-blocking resources
Info::
No render-blocking resources detected
A+Resource Hints208 hints, 0 missing preconnectsPASS
Resource Hints
208 hints, 0 missing preconnects
208 hints, 0 missing preconnects
Info::
Page uses 208 resource hint(s)
Current Resource Hints
preconnect 1
preload 2
dns-prefetch 1
prefetch
+194
204208 resource hints configured
A+HTTP/3 (QUIC)HTTP/3 advertised via Alt-SvcPASS
HTTP/3 (QUIC)
HTTP/3 advertised via Alt-Svc
HTTP/3 advertised via Alt-Svc
Info::
HTTP/3 (QUIC) is supported
First-load mobile users on cellular networks see meaningful latency improvements with HTTP/3. The QUIC transport collapses TLS + TCP handshakes into one and recovers faster from packet loss.
A+Document CompressionDocument response uses brotliPASS
Document Compression
Document response uses brotli
Document response uses brotli
Info::
Main HTML response uses brotli (Content-Encoding: br)
Brotli is the best text-compression algorithm for general use, ~20% smaller than gzip on average (40% on smaller files). Modern browsers all support it.
A+Asset CompressionAll 5 asset hosts use brotliPASS
Asset Compression
All 5 asset hosts use brotli
All 5 asset hosts use brotli
Info::
cdn.shopify.com serves assets with brotli (assets: 8)
Got: cdn.shopify.com (text/javascript)
Info::
js.smile.io serves assets with brotli (assets: 6)
Got: js.smile.io (text/javascript)
Info::
static.klaviyo.com serves assets with brotli (assets: 5)
Got: static.klaviyo.com (application/javascript)
Info::
cdn.jsdelivr.net serves assets with brotli (assets: 3)
Got: cdn.jsdelivr.net (text/css)
Info::
static-tracking.klaviyo.com serves assets with brotli (assets: 3)
Got: static-tracking.klaviyo.com (text/javascript)
A+LCP Image PreloadLCP preload audit not availablePASS
LCP Image Preload
LCP preload audit not available
LCP preload audit not available
Info::
LCP image preload audit not available for this scan
A+Server-Timing Observability18 Server-Timing entries advertisedPASS
Server-Timing Observability
18 Server-Timing entries advertised
18 Server-Timing entries advertised
Info::
Server-Timing header advertises 18 timing entries
A+Server Response Intelligence2 server-response signal(s) detectedPASS
Server Response Intelligence
2 server-response signal(s) detected
2 server-response signal(s) detected
Info::
`Vary` header declared: accept-encoding
The page declares a `Vary` header, telling downstream caches which request headers the response varies on. Critical for content-negotiated responses (compression, language, cookies, device class).
Info::
`ETag` present -- conditional GET supported
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
Render-Blocking Resources
No render-blocking resources detected
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+Third-Party ResourcesNo third-party resources detectedPASS
Third-Party Resources
No third-party resources detected
No third-party resources detected
ACSS Performance Depth1 CSS depth issue(s) detectedPASS
CSS Performance Depth
1 CSS depth issue(s) detected
1 CSS depth issue(s) detected
Warning::
21 render-blocking stylesheet(s) -- recommended: <=3
Each `<link rel="stylesheet">` without a non-blocking `media` attribute holds up the first paint. Browsers download all of them before painting any content. Consolidate into 1-2 critical-path stylesheets; defer non-critical CSS via `<link rel="stylesheet" media="print" onload="this.media='all'">` or via the loadCSS pattern; inline above-the-fold CSS in `<style>` to short-circuit the request entirely.
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
Whether the site is served from green-energy infrastructure
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Network Waterfall374 requests over 5160msINFO
Network Waterfall
374 requests over 5160ms
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
10% of JavaScript execution is third-party
First-party Third-party 514ms · 88KB · £3/mo
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
utt.impactcdn.com utt.impactcdn.com | Other | 119ms | 26 KB | — | £1/mo | Optional |
d2wy8f7a9ursnm.cloudfront.net d2wy8f7a9ursnm.cloudfront.net | Other | 90ms | 12 KB | — | £0/mo | Optional |
static.klaviyo.com static.klaviyo.com | Other | 87ms | 10 KB | — | £0/mo | Optional |
cdn.shopify.com cdn.shopify.com | Other | 55ms | 15 KB | — | £0/mo | Optional |
ajax.googleapis.com ajax.googleapis.com | Other | 55ms | 0 KB | — | £0/mo | Optional |
js.smile.io js.smile.io | Other | 54ms | 24 KB | — | £0/mo | Optional |
js.smile.io js.smile.io | Other | 54ms | 1 KB | — | £0/mo | Optional |
utt.impactcdn.com
Other
Execution 119ms
Transfer 26 KB
Monthly Cost £1/mo
d2wy8f7a9ursnm.cloudfront.net
Other
Execution 90ms
Transfer 12 KB
Monthly Cost £0/mo
static.klaviyo.com
Other
Execution 87ms
Transfer 10 KB
Monthly Cost £0/mo
cdn.shopify.com
Other
Execution 55ms
Transfer 15 KB
Monthly Cost £0/mo
ajax.googleapis.com
Other
Execution 55ms
Transfer 0 KB
Monthly Cost £0/mo
js.smile.io
Other
Execution 54ms
Transfer 24 KB
Monthly Cost £0/mo
js.smile.io
Other
Execution 54ms
Transfer 1 KB
Monthly Cost £0/mo
Real-User Performance (CrUX)Field metrics from the Chrome User Experience ReportINFO
Real-User Performance (CrUX)
Field metrics from the Chrome User Experience Report
Chrome User Experience (CrUX)
Real-user metrics from the Chrome UX Report (2026-09-29 — 2026-10-26)
LCP (p75)
2293 ms
80% good
INP (p75)
142 ms
85% good
CLS (p75)
0.010
99% good
FCP (p75)
1928 ms
TTFB (p75)
918 ms
This origin passes Core Web Vitals assessment
Image Optimization130 images, 1158 KB total, 823 KB wastedINFO
Image Optimization
130 images, 1158 KB total, 823 KB wasted
Image Optimization Audit
Total Images
130
Total Size
1158 KB
Oversized
96
Wasted
823 KB
96 missing dimensions 92 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.