costco.ca

Readiness by lane

Green: costco.ca. Thin bar: E-Commerce & Marketplaces peer median.

Priority fixes for costco.ca

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

1. Priority 1 · Harden

   Framing restricted

   Observed: The homepage did not send frame-ancestors or X-Frame-Options, so other sites may frame it.

   Why it matters: Without it, another site can load your pages in a hidden frame and trick visitors into clicking buttons (clickjacking).

   What to do: Send Content-Security-Policy: frame-ancestors 'self' (or a list of trusted origins). X-Frame-Options: SAMEORIGIN covers older browsers.

   On Next.js: Add it in next.config.js headers().

   70% of E-Commerce & Marketplaces peers do this. Limit: Read from the homepage response only; other pages or regions may send different headers.

   Guide: A Practical Website Health Check for 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 · Enable

   Structured data present

   Observed: The homepage had no JSON-LD structured data.

   What to do: Add JSON-LD for your organization and main content types, then test it with Google's Rich Results Test.

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

   Guide: Structured Data Basics for Website Owners

4. Priority 4 · Harden

   X-Content-Type-Options: nosniff

   Observed: The homepage response did not include X-Content-Type-Options: nosniff.

   What to do: Send X-Content-Type-Options: nosniff on all responses and make sure each file is served with the correct Content-Type.

   On Next.js: Add it in next.config.js headers().

   64% of E-Commerce & Marketplaces peers do this.

   Guide: A Practical Website Health Check for Owners

What costco.ca already does well

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

• HSTS kept for at least a yearHSTS with a 365-day max-age covering subdomains.32% of peers
• DMARC policy enforces quarantine or rejectDMARC policy p=reject.39% of peers
• Modern image formats in useWebP or AVIF images detected.47% of peers

What we saw

Homepage checked

https://www.costco.ca/

Homepage response

HTTP 200

TLS

TLSv1.3, HTTP/2

Certificate

Certainly, 29-day validity, expiring 2026-11-10

Platform or framework

Next.js, Adobe Experience Manager

DNS operators

Akamai Edge DNS

HSTS

max-age 365 days, includeSubDomains

DMARC policy

p=reject

Homepage HTML

2,538 KB, gzip

Images on homepage

66 (avif 244, png 20)

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

Compare with other E-Commerce & Marketplaces sites

• chasevalue.pk76
• coca-cola.com76
• conforama.es76
• costcobusinesscentre.ca76
• crossstitch.pk76

E-Commerce & Marketplaces readiness benchmark