A Tolgee alternative for translating files without a platform

Tolgee is an open-source localization platform: a web editor, in-context translation inside your app, SDKs and seats for a team, in their cloud or on your own server. KAERIS does one part of that. It translates the string files in your repository into 46 languages and checks every line, with no account to start.

Translate your file Check your files free

A JSON file with ICU plurals, translated

Plural branches and {name} come back intact; keys and their order do not change.

Beforeen.json

{
  "cart": {
    "title": "Your cart, {name}",
    "items": "{count, plural, one {# item} other {# items}}"
  }
}

Afterde.json

{
  "cart": {
    "title": "Dein Warenkorb, {name}",
    "items": "{count, plural, one {# Artikel} other {# Artikel}}"
  }
}

KAERIS and Tolgee, side by side

Tolgee is where a team works on the strings. KAERIS is a tool you point at a file.

What	Tolgee	KAERIS
What it is	An open-source localization platform for teams	A tool that translates and checks files
Start without an account	No: an account, or your own server	Yes
Web editor and seats for a team	Yes	No
Host it on your own servers	Yes	No

Entry price, side by side

Tolgee prices by hosted words, in euros on the page we saw. We price by characters per file.

What	Tolgee	KAERIS
Cheapest paid plan	€58/mo (Translate), billed annually	$19/mo (Pro), or $79 once
Free plan	€0: 30,000 words, 3 seats, no card	10,000 characters per file, no account
Pay once, no subscription	No; self-hosting is free, paid licences are monthly or annual	$79 Lifetime, on your own OpenRouter key

Tolgee figures read from their pricing page on 1 November 2026, in the currency shown to us; prices change and theirs is the authority. Ours are on our pricing page.

When Tolgee is the better choice

Translators, reviewers or product people edit the strings together in one web editor.
You want to fix a string by clicking it inside your running app.
The whole platform has to run on your own servers.

What KAERIS does with it

No seats, no project set-up
Drop the file, pick languages, download. The free tier needs no account.
Variables checked without AI
After translation a plain counting check compares every variable and tag with the original. A line that lost one is marked and shown on top.
Each line translated back
A different model, Gemini 2.5 Flash-Lite, translates every line back into your language, and DeepSeek V3.2 on US hosts (DeepInfra, DigitalOcean, Google) judges whether the meaning changed. You read what each line now says.
One agreed word per term
Terms go into kaeris-glossary.json. translate uses them, and check fails a line that uses another word. How the glossary works

Translate your file Check your files free

Questions

Do I need an account or API key to try KAERIS?

No. Up to 10,000 characters per file and 8 languages per run work with no account.

Can it run in CI?

Yes. The GitHub Action has two modes: translate opens a pull request, check runs offline and fails the build on a broken translation. Docs

Is it free?

Yes, without an account: 10,000 characters per file and up to 8 languages per run. A free API key raises the file limit to 50,000 characters. Lifetime is $79 once, on your own OpenRouter key; monthly plans start at $19. Pricing

Which one should I choose?

A team that edits strings together in one place: Tolgee. Files in your repository that need translating and checking: KAERIS.