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gakken.co.jp

ホーム | 株式会社学研ホールディングス

Last scanned Jul 26, 2026, 1:19 PM

80

Overall score

Great

Summary

株式会社学研ホールディングスの公式サイト。企業概要、IR、社会・環境、採用などの企業情報のほか、学研グループの書籍、商品、サービス、教育などの各種事��… This website uses Apache behind CloudFront CDN. SEO is fair (70/100) and accessibility is excellent (100/100). Security scores fair (65/100) and performance excellent (90/100). Top issue: Meta description longer than 160 characters.

株式会社学研ホールディングスの公式サイト。企業概要、IR、社会・環境、採用などの企業情報のほか、学研グループの書籍、商品、サービス、教育などの各種事業のご紹介

Top issues to fix

10 issues found · 2 high priority

  • Missing Strict-Transport-Security header

    Security

    Add HSTS so browsers always use HTTPS — this closes the protocol-downgrade attack window.

  • Missing Content-Security-Policy header

    Security

    Add a CSP to control which sources can run scripts — the strongest single defense against XSS.

  • Missing X-Content-Type-Options header

    Security

    Add X-Content-Type-Options: nosniff to stop MIME-sniffing attacks.

  • Missing X-Frame-Options header

    Security

    Add X-Frame-Options (or a CSP frame-ancestors rule) to prevent clickjacking via hidden iframes.

  • Meta description longer than 160 characters

    SEO

    Trim the meta description to under 160 characters to avoid truncation in search results.

  • Missing canonical link

    SEO

    Add <link rel="canonical"> so search engines know which URL variant to index.

+4 more issues — details in the sections below.

70

SEO

5 issue(s) found

90

Performance

2.42 s

65

Security

HTTPS & header checks

100

Accessibility

0 issue(s) found

Not enough scan history yet to show a trend — check back after this site has been re-scanned a few more times.

Organization

Company details published in this site's own structured data.

株式会社学研ホールディングスの公式サイト。企業概要、IR、社会・環境、採用などの企業情報のほか、学研グループの書籍、商品、サービス、教育などの各種事業のご紹介

Meta tags

Title
ホーム | 株式会社学研ホールディングス
Description
株式会社学研ホールディングスの公式サイト。企業概要、IR、社会・環境、採用などの企業情報のほか、学研グループの書籍、商品、サービス、教育などの各種事業のご紹介
Canonical
Language
ja
Charset
utf-8
Viewport
width=device-width
Robots meta
all
Manifest

OpenGraph & Twitter Card

OpenGraph

og:title
ホーム | 株式会社学研ホールディングス
og:description
株式会社学研ホールディングスの公式サイト。企業概要、IR、社会・環境、採用などの企業情報のほか、学研グループの書籍、商品、サービス、教育などの各種事業のご紹介
og:type
article
og:url
https://www.gakken.co.jp/ja/index.html

Twitter Card

twitter:card
—
twitter:title
—
twitter:description
—

Technologies

Detected frameworks, languages, and tools.

Google AnalyticsApache

Hosting & CDN

Hosting provider
—
CDN provider
CloudFront
IP address
—
ASN
—

DNS records

TypeValue
A—
AAAA—
MX—
TXT—
NS—
CAA—
CNAME—
IPv6 supportNo

TLS / SSL certificate

Version
TLS 1.3
Issuer
GlobalSign nv-sa
Subject
www.gakken.co.jp
Valid from
Jul 6, 2026
Valid to
Jan 21, 2027
Days until expiry
176
SAN domains
www.gakken.co.jp, corp-gakken.co.jp, gakken-educational.co.jp, gakken-kyoikumirai.co.jp, gakken-leap.co.jp, gakken-link.co.jp, gakken-meds.co.jp, gakken-mesh.co.jp, gakken-method.co.jp, gakken-plus.co.jp, gakken-ps.co.jp, gakken-seed.co.jp, gakken-smileheart.co.jp, gakken-smileheartful.co.jp, www.corp-gakken.co.jp, www.gakken-plus.co.jp, www.glg.co.jp, cocofump.gakken.co.jp, khd.gakken.co.jp, saiyo.gakken.co.jp, thinquest.gakken.co.jp, gakken.co.jp

Security headers

  • Strict-Transport-SecurityMissing
  • Content-Security-PolicyMissing
  • X-Frame-OptionsMissing
  • X-Content-Type-OptionsMissing
  • Referrer-PolicyMissing
  • Permissions-PolicyMissing

Compression: gzip · 0 cookie(s) observed

Content & assets

Headings

H1 1 · H2 25 · H3 0

Links

43 internal · 6 external · 20 broken

Images

21 total · 0 missing alt

Scripts / Styles

30 scripts · 5 stylesheets

JS / CSS size

5.1 KB · 0 B

Page size

55.2 KB

Robots.txt & Sitemap

robots.txt
Not found
Disallow rules
0
sitemap.xml
Not found
URLs in sitemap
0

SEO issues

  • Meta description longer than 160 characters
  • Missing canonical link
  • No structured data (JSON-LD) found
  • robots.txt not found
  • sitemap.xml not found

Accessibility issues

No accessibility issues detected.

Scan details

Requested URL
https://gakken.co.jp
Final URL
https://www.gakken.co.jp/ja/index.html
HTTP status
200
HTTP version
HTTP/2
Response time
2.42 s
HTML size
55.2 KB
Redirect chain
https://gakken.co.jp → https://www.gakken.co.jp/ → http://www.gakken.co.jp/ja/index.html → https://www.gakken.co.jp/ja/index.html

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Frequently asked questions

What technology does gakken.co.jp use?
gakken.co.jp is built with Google Analytics, Apache.
Is gakken.co.jp secure (HTTPS)?
Yes. gakken.co.jp uses TLS 1.3 with a certificate issued by GlobalSign nv-sa, valid until Jan 21, 2027.
Who hosts gakken.co.jp?
Hosting provider information for gakken.co.jp is not available yet.
What is gakken.co.jp's SEO score?
gakken.co.jp scored 70/100 for SEO in the latest analysis (fair).
What is gakken.co.jp's overall website score?
gakken.co.jp has an overall SiteGraph score of 80/100, combining SEO, performance, security, and accessibility.