marksandspencer.com

Readiness by lane

Green: marksandspencer.com. Thin bar: E-Commerce & Marketplaces peer median.

Priority fixes for marksandspencer.com

Ordered by impact and by how common each practice is among peers.

1. Priority 1 · Harden

   HSTS kept for at least a year

   Observed: Strict-Transport-Security was sent with a max-age of 183 days, below the one-year benchmark.

   Why it matters: HSTS tells browsers to use HTTPS for your host on every later visit, which removes the window where a first HTTP request can be intercepted.

   What to do: Send Strict-Transport-Security on HTTPS responses. Start with a short max-age (for example 300 seconds), confirm every subdomain works over HTTPS, then raise it in steps to 31536000. Add includeSubDomains only when all subdomains are HTTPS. HSTS preload is optional and hard to undo; hstspreload.org itself does not recommend it by default.

   On Azure Front Door/CDN: Add a response header action in a Front Door rule set.

   32% of E-Commerce & Marketplaces peers do this. Limit: Read from the homepage response only; other pages or regions may send different headers.

   Guide: HTTPS and TLS Guide for Website Owners

2. Priority 2 · Accelerate

   No render-blocking scripts in <head>

   Observed: The homepage <head> loaded 2 external scripts without async or defer.

   What to do: Add defer to scripts that need the DOM, async to independent ones such as analytics, or move them to the end of the body.

   On Next.js: Use the next/script component with an appropriate loading strategy.

   44% of E-Commerce & Marketplaces peers do this.

   Guide: Control Third-Party Scripts Before They Control Your Page

3. Priority 3 · Accelerate

   HTTP/3 advertised

   Observed: The homepage did not advertise HTTP/3 through an Alt-Svc header.

   What to do: Turn on HTTP/3 at your CDN. Browsers fall back to HTTP/2 automatically, so the risk is low.

   47% of E-Commerce & Marketplaces peers do this.

   Guide: CDN Guide for Website Owners

4. Priority 4 · Harden

   Certificate lifetime of 100 days or less

   Observed: The certificate from DigiCert Inc had a 364-day validity period, longer than the 100-day maximum that applies from March 2027.

   What to do: Move to automated issuance and renewal now, while you still have time to test it.

   70% of E-Commerce & Marketplaces peers do this.

   Guide: HTTPS and TLS Guide for Website Owners

What marksandspencer.com already does well

Practices fewer than half of E-Commerce & Marketplaces peers use.

• DMARC policy enforces quarantine or rejectDMARC policy p=reject.39% of peers
• Modern image formats in useWebP or AVIF images detected.47% of peers
• Content Security Policy presentContent-Security-Policy present.48% of peers

What we saw

Homepage checked

https://www.marksandspencer.com/

Homepage response

HTTP 200

TLS

TLSv1.3, HTTP/2

Certificate

DigiCert, 364-day validity, expiring 2026-11-30

CDN or edge

Akamai, Azure Front Door/CDN

Platform or framework

Next.js

DNS operators

Akamai Edge DNS

HSTS

max-age 183 days

DMARC policy

p=reject

Homepage HTML

564 KB, gzip

Images on homepage

49 (jpg 87, svg 15)

Limits: homepage only, one location, one moment. Header checks reflect the homepage response; other pages may differ.

Stack and providers

Seen in the homepage response, certificate and DNS. Provider pages compare how their customers configure the same checks.

All 31 checks

Select a gap for the method and fix. How each check works

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E-Commerce & Marketplaces readiness benchmark