octopusenergy.co.jp

Readiness by lane

Green: octopusenergy.co.jp. Thin bar: Energy, Electricity & Gas peer median.

Priority fixes for octopusenergy.co.jp

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

1. Priority 1 · Accelerate

   Modern image formats in use

   Observed: The homepage had 5 images and none used WebP or AVIF.

   Why it matters: WebP and AVIF are typically much smaller than JPEG or PNG at similar quality, and images are often the heaviest part of a page.

   What to do: Serve WebP or AVIF with a JPEG or PNG fallback, either through an image CDN or by generating both formats at build time.

   On Vercel: Vercel Image Optimization serves modern formats.

   36% of Energy, Electricity & Gas peers do this. Limit: Based on the homepage HTML delivered to an automated client; scripts that run later were not executed.

   Guide: AVIF, WebP, JPEG, and PNG: Choose the Right Image Format

2. Priority 2 · Harden

   Framing restricted

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

   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().

   75% of Energy, Electricity & Gas peers do this.

   Guide: A Practical Website Health Check for Owners

3. Priority 3 · Enable

   Canonical URL declared

   Observed: The homepage did not declare a canonical URL.

   What to do: Add a self-referencing canonical link to every indexable page, using the final https:// URL.

   68% of Energy, Electricity & Gas peers do this.

   Guide: Canonical Tags: A Decision Guide for Duplicate URLs

4. Priority 4 · Harden

   Content Security Policy present

   Observed: The homepage response did not include a Content-Security-Policy header.

   What to do: Start with Content-Security-Policy-Report-Only to see what would break, tighten the policy over a few weeks, then enforce it.

   On Next.js: Next.js documents nonce-based CSP with middleware.

   50% of Energy, Electricity & Gas peers do this.

   Guide: Payment Security and PCI DSS: What Website Owners Need to Know

What octopusenergy.co.jp already does well

Practices fewer than half of Energy, Electricity & Gas peers use.

• security.txt publishedsecurity.txt with a contact found.7.9% of peers
• Certificate lifetime of 100 days or lessShort-lived 89-day certificate from Let's Encrypt, already inside the 2027 limit.35% of peers
• Static files cached for 30 days or moreLong-lived caching on static files.41% of peers

What we saw

Homepage checked

https://octopusenergy.co.jp/

Homepage response

HTTP 200

TLS

TLSv1.3, HTTP/2

Certificate

Let's Encrypt, 89-day validity, expiring 2026-12-22

CDN or edge

Vercel

Platform or framework

Next.js

DNS operators

Amazon Route 53

HSTS

max-age 730 days

DMARC policy

p=reject

Homepage HTML

1,145 KB, br

Images on homepage

5 (svg 1, png 1)

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 Energy, Electricity & Gas sites

• bharatpetroleum.in70
• britishgas.co.uk71
• edf.fr70
• firstenergycorp.com68
• fpl.com67

Energy, Electricity & Gas readiness benchmark