First CH Apps / Japanese Business Tone Check
Paste a Japanese email or proposal before you send it. It flags phrases by how the recipient is likely to read them — rude, vague, double keigo (incorrect honorifics) or too pushy — and suggests Japanese rewrites you can drop in. It also notes spots that are easily misunderstood if you translate the text into English for an overseas reader.
This is not a spelling or grammar checker (use a proofreading tool for that). It only looks at how the text will be received.
Only the text you enter is sent. Our server (Cloudflare Pages Functions) passes it to Cloudflare Workers AI (a language model running on Cloudflare) and returns the result. Cloudflare handles it under its own terms.
Your text and the result are not stored (not in a database, not in logs). They are gone when the request ends.
The only thing written to the database is the date and the total number of checks that day across all users (there is a daily cap to stay within the free tier). To prevent rapid repeat submissions we count requests per IP address in server memory only; nothing is saved and the count is gone within 10 minutes.
We recommend masking personal names, contact details and confidential content before pasting.
POST JSON ({"text": "…"}) to /tone-check/api/check to get the same result as JSON (no auth, nothing stored; the daily cap and per-IP limit are shared with this page).