Next.js
next-intl · App Router · ICU · 46 languages · Free

Translate next-intl's messages/en.json, then read every line back before you ship

Upload messages/en.json — KAERIS translates all 46 languages, then reads each line back to you in your own language and flags the ones worth a second look. Catch the shaky ones before release, not after. Nested namespaces and ICU plural/select blocks stay intact.

Translate your messages file $ pip install kaeris
✓ Nested-namespace safe ✓ ICU MessageFormat aware ✓ CLDR plural categories with Smart plurals on ✓ App Router ready ✓ No account needed
Localize your Next.js app in 3 steps
1

Upload messages/en.json

Or run kaeris init --preset next-intl to scan your messages/ folder automatically.

2

Pick locales

Matched 1:1 to your [locale] route segments — no renaming needed.

3

Ship

Drop the output into messages/, wire up next-intl's routing — done.

ICU translated per-branch, per-locale plural rules

Before → after

messages/en.json 
{
  "HomePage": {
    "title": "Welcome, {name}!",
    "cartItems": "{count, plural, =0 {Your cart is empty} one {# item} other {# items}}"
  }
}
messages/ja.json 
{
  "HomePage": {
    "title": "ようこそ、{name}さん！",
    "cartItems": "{count, plural, =0 {カートは空です} other {カートに#点の商品があります}}"
  }
}

Turn on Smart plurals and KAERIS asks the model to emit every plural category the target locale needs — Russian gets few/many, not just one/other — and the built-in CLDR check flags any translation that's still missing one.

Built for next-intl

Nested-namespace safe

Dotted structures like HomePage.title keep their exact nesting — nothing gets flattened or re-keyed.

ICU-aware

plural, select and selectordinal blocks are preserved verbatim and translated as one unit — the variable, the structure and the branch keywords stay intact. Enable Smart plurals and the model fills in the CLDR categories the locale needs; the CLDR check flags any that are still missing.

App Router ready

Output drops straight into your [locale] messages — no reshaping for getRequestConfig.

One CLI command

kaeris init --preset next-intl scaffolds locale detection from your existing messages/ folder.

Why KAERIS
✓ Placeholder-safe — {name} / {count} is never dropped or mistranslated.
✓ Format-native — real ICU MessageFormat out, not a flattened wrapper you have to reshape.
✓ Verify-meaning QA — every string is back-translated to catch meaning drift before you ship.
✓ No account needed — drag & drop free up to 10,000 characters, or use the CLI/API.
✓ Honest flat pricing — no per-seat, no per-language multiplier. See plans

Beyond next-intl's ICU JSON, KAERIS speaks all 11 formats — JSON, YAML, .strings, .po, ARB, Android XML, CSV (incl. Godot/Unity), XLIFF, .properties, .resx and Mozilla Fluent (.ftl) — same placeholder-safe engine across your whole stack.

Ship next-intl in every market

46 languages, ICU-safe, App Router ready. Free to start, no account required.

$ pip install kaeris
$ kaeris init --preset next-intl
Translate your messages files now