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Energy, telecoms & utilitieswww.o2.co.uk

O2 — website check

Global brand name owned by the Spanish telecommunications company Telefónica, founded 2001, based in Slough. O2’s website (www.o2.co.uk) runs on Next.js. It is delivered through Azure Front Door / CDN. There is no DMARC record, so the domain can be spoofed in email.

Logo: Telefónica Germany GmbH & Co. OHG · Public domain · Wikimedia Commons
45
Brand Web Indexout of 100

Share of 26 technical checks the site passes: security, speed, email and SEO. A measurement of the website — not a popularity ranking.

67
Security
40
Speed & delivery
13
Email & domain
55
SEO & markup
Official siteChecked 22 Oct 2026

About the brand

Founded2001
CountryUnited Kingdom
HeadquartersSlough
IndustryTelecommunications · Telecommunications industry
Part ofTelefónica
Official websitewww.o2.co.uk

Facts: Wikidata (CC0).

Built with

Tag managersGoogle Tag Manager
CDNAzure Front Door / CDNGoogle Cloud CDN / GFE
Web frameworksNext.jsReact
JavaScript librariesSwiper
A/B testingOptimizely
Monitoring & RUMSpeedCurve LUX

Hosting & delivery

Network (AS)Microsoft Azure
HTTP versionHTTP/3
TLSTLS 1.3
CertificateDigiCert Inc · valid until 2027-04-07
First response10,157 ms
Homepage weight488 KB
IPv6no

Email & domain

SPFyes
DMARC policyno
BIMIno
DNSSECno
CAAno
Verified servicesMeta Business (domain verification), Google Search Console

SEO & social

Title25 characters
Meta description138 characters
Canonicalyes
Structured datano
Language versions0
Open Graphno
Social profiles linkedFacebook, Instagram, X, Youtube

AI crawlers & robots

AI crawlers blockednone
llms.txtno
ads.txtno
security.txtno

Checklist

Security

  • HTTPS by default
  • HSTS header
  • TLS 1.3
  • Content-Security-Policy
  • X-Content-Type-Options
  • Referrer-Policy

Speed & delivery

  • HTTP/3
  • IPv6
  • First response under 1.5 s
  • Homepage under 1.5 MB

Email & domain

  • SPF record
  • DMARC record
  • DMARC enforced (quarantine / reject)
  • BIMI logo record
  • DNSSEC
  • CAA record

SEO & markup

  • Title tag 10–70 characters
  • Meta description
  • Canonical link
  • Exactly one H1
  • Structured data (JSON-LD)
  • Open Graph title and image
  • All images have alt text
  • XML sitemap
  • robots.txt
  • security.txt

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Data from our own crawler: homepage, DNS, TLS and robots.txt of each brand’s official website. coolbrands.uk.com is an independent catalogue. It is not affiliated with Superbrands (UK) Ltd or the CoolBrands® awards programme, and does not publish their results.

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