www.walmart.com

The numbers

First visit

0.801 g CO₂e

Return visit

0.058 g CO₂e

Hosting

unknown

LCP

440 ms

CLS

0.004

TTFB

28 ms

At 10,000 views a month this page emits about 73.9 kg CO₂e a year, roughly 303 km in an average petrol car. The estimate assumes 75% new and 25% returning visitors, a measured cache reload ratio of 7%, and world-average grid intensity. How we calculate this

1. Audit third-party servicessave ~0.277 g/visit (2.43 MB)High impact · moderate effort

   12 third-party domains account for 4.86 MB (90% of the page).

   Remove services that no longer earn their place; load the rest on interaction (facades for embeds, delayed consent-gated tags). Each third party is also a privacy and performance dependency.

   • i5.walmartimages.com4.05 MB
   • crcldu.com647 kB
   • client.px-cloud.net142 kB
   • collector-pxu6b0qd2s.px-cloud.net6.2 kB
   • dvp.px-cloud.net5.0 kB
   • fst-ec.perimeterx.net3.0 kB

   WSG 3.5: Treat third parties the same as first parties
2. Reduce JavaScript payloadsave ~0.115 g/visit (1.01 MB)High impact · moderate effort

   255 scripts total 4.06 MB on the wire (12.59 MB decoded). Bundles this size usually carry a lot of unused code.

   Split bundles per route, tree-shake dependencies, and audit with a bundle analyzer or coverage profile. A 25% cut is a conservative target for bundles this size.

   • _app-9a1d7ec0b72369a2.js764 kB
   • auditor.js323 kB
   • auditor.js322 kB
   • captcha.js278 kB
   • 7272-a7078e2510881b6a.js168 kB

   WSG 3.2: Minify and remove unused codeWSG 3.3: Modularize bandwidth-heavy components
3. Fix caching for returning visitorssave ~0.010 g/visit (70 kB)Medium impact · quick fix

   On a repeat visit 278 kB of static assets were re-downloaded instead of coming from cache.

   Serve static assets with Cache-Control: public, max-age=31536000, immutable and versioned filenames so returning visitors download almost nothing.

   • captcha.jsCache-Control: max-age=0, no-cache, no-store · 278 kB

   WSG 4.2: Optimize caching and support offline access
4. Verify your hosting energyMedium impact · moderate effort

   This host has not published renewable energy evidence with the Green Web Foundation, so its energy source is unknown.

   Choose a provider listed in the Green Web Directory, or ask your current provider to publish evidence (and a carbon.txt). This cuts the data-center share of every single page view.

   • carbon.txtNo carbon.txt found at the site root; publishing one is the lightest first step.

   WSG 4.1: Use sustainable hosting
5. Stop downloading the same asset twicesave ~0.031 g/visit (269 kB)Advisory · quick fix

   108 assets were fetched more than once in a single page load (1.25 MB of repeated transfer).

   Usually a script injected twice or cache-busting query strings that differ per reference. Load each asset once and let the HTTP cache do its job.

   • init.js2 downloads · 155 kB
   • collector2 downloads · 2.5 kB
   • rum.gif4 downloads · 5.4 kB
   • 47869-28ab38e9d5fc6ba7.js2 downloads · 8.4 kB
   • 96672-b3f84996de36590d.js2 downloads · 7.3 kB

   WSG 3.2: Minify and remove unused code
6. Upgrade compression beyond gzipsave ~0.023 g/visit (200 kB)Advisory · quick fix

   1.34 MB of text ships gzip-compressed; Brotli or Zstandard would cut roughly another 15-20%, and browsers without them fall back to gzip automatically.

   Serve precompressed Brotli for static text assets (highest level, compressed at build time) and enable Brotli or zstd for dynamic responses; keep gzip only as the fallback.

   • auditor.js323 kB
   • auditor.js322 kB
   • captcha.js278 kB
   • init.js155 kB
   • main.min.js141 kB

   WSG 4.3: Reduce data transfer with compression
7. Remove references to broken resourcessave ~<0.001 g/visit (1.6 kB)Advisory · quick fix

   1 request answered 4xx/5xx on load: transfer and connections spent on nothing, on every single visit.

   Delete or fix the references (stale asset URLs, dead third-party tags). Each one is a request the page provably does not need.

   • 26e4ca8c866334908ce825a5749f6aa13f772b98a527b…HTTP 412 · 1.6 kB

   WSG 4.4: Setup necessary error pages and redirection links
8. Set a page-weight budgetAdvisory · moderate effort

   At 5.41 MB per view this page rates F. The findings above list where the weight is.

   Agree a transfer budget (e.g. under 975 kB reaches a B), enforce it in CI, and re-scan after each change to hold the line.

   WSG 3.1: Set goals based on performance and energy impact
9. Remove the entry redirectAdvisory · quick fix

   The address that was scanned goes through 1 redirect before the document is served, ending at https://www.walmart.com/. Every hop is a full round trip on a connection that has not warmed up yet.

   Point links, sitemaps and canonical tags at the final address, and make the host redirect in one hop rather than chaining http to https to www.

   • https://walmart.com/redirects to https://www.walmart.com/

   WSG 4.4: Setup necessary error pages and redirection links
10. Upgrade connections to HTTP/2 or HTTP/3Advisory · quick fix

    1 host serves five or more resources over HTTP/1.1, paying per-request connection and header overhead newer protocols eliminate.

    Enable HTTP/2 (or HTTP/3) on the server or move the assets behind a CDN that speaks it; multiplexing makes many small requests nearly free.

    • b.www.walmart.com5 requests over http/1.1

    WSG 3.1: Set goals based on performance and energy impact

Where the bytes are

• JavaScript4.06 MB · 255 req
• Other920 kB · 105 req
• Images182 kB · 23 req
• HTML96 kB · 4 req
• CSS71 kB · 2 req
• Fonts63 kB · 3 req
• Data (XHR)17 kB · 12 req
• Data (fetch)1.6 kB · 1 req