Website Localization for Japan: The Technical and Compliance Checklist (2026)

Deciding to localize for Japan is the strategic call; actually shipping a Japanese website is an engineering, content and compliance project with a dozen places to go wrong. This guide is the practical checklist: how to structure URLs and hreflang so Google indexes the Japanese version, what the Japanese pages must contain (including a legally required one for ecommerce), how to keep Japanese typography from wrecking Core Web Vitals, and how to QA the result.

It assumes you’ve read the strategic case in Japanese Localization and understand the vendor/workflow options in Localization in Japan. This article is about the build.

1. URL Structure and Indexing

Google’s multi-regional guidance lists four structures. For a foreign company adding Japanese, the practical choice is between two:

Two more rules from the same guidance: don’t auto-redirect visitors by IP or browser language (“Google might not find and crawl all your variations” — Googlebot mostly crawls from the US), and keep URLs in Latin characters (romaji or English slugs) rather than percent-encoded Japanese — cleaner sharing, analytics and hreflang. Offer a visible language switcher instead of forced redirects.

2. hreflang Done Right

Google’s hreflang rules are strict and commonly botched:

• Every version lists every version, including itself. “If two pages don’t both point to each other, the tags will be ignored.” Self-referencing is required.
• Codes: ISO 639-1 language, optional ISO 3166-1 region: ja or ja-JP, en / en-US. Use ja unless you genuinely serve different Japanese for different regions.
• x-default: designate the fallback page (usually English or a language selector) for unmatched users.
• Three delivery methods — HTML <link rel="alternate" hreflang>, HTTP headers, or XML sitemap — pick one and be consistent. Sitemap is easiest to maintain at scale.

Minimal example for an English/Japanese page pair:

<link rel="alternate" hreflang="en" href="https://example.com/pricing/" />
<link rel="alternate" hreflang="ja" href="https://example.com/ja/pricing/" />
<link rel="alternate" hreflang="x-default" href="https://example.com/pricing/" />

Also set <html lang="ja"> on Japanese pages, and give them their own Japanese titles and meta descriptions (full-width characters truncate at roughly 30–32 for titles — see Japanese SEO). Website translation platforms typically handle URL translation and hreflang automatically; verify the output rather than assuming it.

3. Pages the Japanese Site Must Have

Company profile (会社概要)

Japanese visitors — consumer and B2B — look for a formal company page: legal name, address, establishment date, representative, capital, business description. A localized site without one reads as untrustworthy regardless of design quality.

Specified Commercial Transactions Act disclosure (特定商取引法に基づく表記)

If you sell goods or services online to consumers in Japan, Japanese law requires a disclosure page — and it applies even without a Japanese entity. Conventionally titled “特定商取引法に基づく表記” and linked from the footer, it must state, in Japanese, items including: seller name, address and phone number; sales price and shipping costs; payment methods and timing; delivery timing; and return/cancellation terms. Payment providers such as KOMOJU and Adyen list the required items and often check for the page during onboarding.

Privacy policy and legal pages in Japanese

Translate the privacy policy and terms; if you collect personal data from Japanese users, review obligations under Japan’s Act on the Protection of Personal Information (APPI). Trust badges, security statements and support hours (in JST) belong near forms and checkout.

4. Typography and Performance

Japanese text breaks assumptions baked into English-first CSS:

• Font weight in bytes. Full Japanese fonts (e.g., Noto Sans JP) run to many megabytes per weight because they carry thousands of kanji. Ship a subset (WOFF2, unicode-range slices or a curated glyph set), limit weights, and self-host or use a CDN that serves slices — or fall back to system Japanese fonts (Hiragino, Yu Gothic, Noto on Android) for body text.
• CLS from font swap. Use font-display: swap so text renders immediately, and tune the fallback with size-adjust / ascent-override / descent-override so the swap doesn’t shift layout.
• Line breaking. Japanese has no spaces, so browsers can break between almost any two characters. Set line-break: strict to enforce Japanese kinsoku rules (no line starting with a closing bracket or small kana, for example) — it’s widely supported — and avoid word-break: break-all on Japanese text. Then test headings: awkward mid-phrase breaks are the most common visual defect on localized sites, and are usually fixed by manual line-break hints (<wbr> or <br> in headings) rather than CSS alone.
• Vertical rhythm. Japanese glyphs are visually denser and taller; increase line-height (1.7–1.9 for body text is common) and reduce letter-spacing on Latin/Japanese mixes.
• String expansion in UI. Japanese can be shorter or longer than English depending on the phrase; buttons, nav labels and table headers must not truncate. Test with real translations, not lorem ipsum.

5. Forms, Checkout and Support Localization

• Names: family name first, split into family/given fields; separate furigana (phonetic kana) fields are standard on Japanese forms and Chrome can autofill them when labeled and named conventionally.
• Addresses: postal code first (〒123-4567), then prefecture, city, street, building; postal-code lookup that auto-fills is expected.
• Phone / dates / currency: Japanese formats, tax-inclusive price display for consumers, and yen with no decimals.
• Payments: cards plus konbini, PayPay and bank transfer where you sell to consumers (see Selling to Japan).
• Validation messages and emails: the most-forgotten strings; machine-translated error messages destroy trust at the exact moment a user is frustrated.
• Support: Japanese-language contact form, response-time expectations, and JST business hours stated plainly.

6. Content Localization Priorities

Order of work when you can’t do everything at once: (1) homepage, pricing and top landing pages — transcreated by a native marketing writer; (2) company profile, legal and disclosure pages; (3) product/feature pages and FAQs — translated with native review; (4) blog/help content — platform-assisted with spot checks. Terminology decisions in step 1 should already be validated against Japanese search data, since they determine what you can rank for.

7. Analytics and Search Console

• Register the Japanese section (subdirectory or subdomain) in Google Search Console and monitor Japanese queries separately.
• Segment analytics by language path (/ja/) so Japanese conversion rates aren’t buried in global averages.
• Track hreflang errors in Search Console’s international targeting reports and crawl the site with a tool that validates return links.

8. QA Checklist Before Launch

1. Every Japanese page has lang="ja", a Japanese title/description, and correct bidirectional hreflang including self-reference.
2. No auto-redirects by IP/language; language switcher visible on every page.
3. Company profile, privacy and (if selling to consumers) the Specified Commercial Transactions Act page exist and are footer-linked.
4. Fonts subset; LCP and CLS checked on a mid-range Android device over mobile network.
5. Headings and buttons reviewed for line breaks and truncation on 360–390px screens.
6. Forms accept Japanese input, postal-code lookup works, validation messages are native Japanese.
7. Checkout offers Japanese payment methods; test transactions and confirmation emails reviewed in Japanese.
8. Native reviewer sign-off on all customer-facing pages (the “would a Japanese company publish this?” test).

Tools

Website translation platforms handle much of the mechanical layer — content detection, translated URLs, hreflang — so your team can focus on quality and compliance:

More options in the Localization section and our Tools directory.

Where to Go Next

The strategy behind these steps is in Japanese Localization; vendor selection, in-country review and cost live in Localization in Japan; and turning the localized site into rankings is covered in Japanese SEO.