I scored 40 popular dev tools on one question: if a Japanese company wanted to buy you today, could they?
Not "is your product good." It is. I mean the boring buying surface — the page Japanese corporate procurement opens before they're allowed to approve spend, the currency on your pricing page, whether /ja 404s.
I checked all 40 live and scored them 0–100 on five signals:
- a 特商法 (Tokushoho) page — the disclosure page Japanese commercial law expects from any paid online service
- a real localized Japanese site (not a
/jaroute that 200s but serves an English shell) - Japanese content / a language switcher
hreflang="ja"- pricing shown in JPY
Every score is formula-derived from evidence, not hand-assigned. A /ja that returns an English SPA scores zero — localization is judged on rendered Japanese, not route existence.
The results
- 0 of 40 have a 特商法 page.
- 0 of 40 price in JPY.
- Average score: 5.6 / 100. The highest was 60. 31 of 40 scored zero.
The top three — Auth0, Twilio Segment, HashiCorp — are the only ones with a genuinely localized Japanese site. All three still skip 特商法 and JPY.
The bottom is a who's-who: Vercel, Supabase, Linear, Clerk, Neon, Sentry, Algolia, Retool — lang="en", /ja 404, no hreflang, USD only.
Three patterns I kept hitting
-
"Looks localized, isn't." Vercel / Linear / Sentry have a
/jaroute that returns 200 — and serves English. The route exists to look ready; the content was never translated. - Localized everywhere except Japan. Algolia ships EN/DE/FR/PT/ES/IT and skipped Japanese specifically.
- Product localized, storefront not. Appwrite, Logto, ToolJet ship a Japanese product UI but an English buying page — so a Japanese dev can use it but their finance team can't cleanly pay for it.
Why it matters
None of this is an engineering problem. The products are excellent. The gap is at procurement: a Japanese buyer hits the missing 特商法 page, the USD-only price, the 404 on /ja, and quietly stalls — usually before anyone tells you why.
For context, I've been sending Japanese-localization PRs to a bunch of these (a couple merged into Jan this week; an IME-composition fix into another). The product side is fixable in an afternoon. It's the commercial surface that nobody owns.
The full scored list, with an evidence link on every signal, is here:
https://greymoth-jp.github.io/japan-readiness-index/
If your tool is on it and you think the score is wrong, the evidence is right there — tell me what I missed.
