A Lingo.dev alternative that needs no account to start
Both translate your app with AI and ship a command-line tool, a GitHub Action and an MCP server. Lingo.dev is a configurable engine with plans priced by usage. KAERIS translates the files already in your repository, free to start, with an offline check for CI.
A next-intl file, translated in the repository
ICU branches and {name} stay valid for the App Router.
{
"Inbox": {
"title": "Hi {name}",
"unread": "{count, plural, one {# unread message} other {# unread messages}}"
}
}
{
"Inbox": {
"title": "Hola {name}",
"unread": "{count, plural, one {# mensaje sin leer} other {# mensajes sin leer}}"
}
}
KAERIS and Lingo.dev, side by side
Similar tools, different shapes: an engine you configure against a tool you point at a file.
| What | Lingo.dev | KAERIS |
|---|---|---|
| What it is | A localization engine with quality measurement | A tool that translates and checks files |
| Start without an account | No: an API key first | Yes |
| Open-source command-line tool | Yes | Yes |
| Priced by | A plan fee plus tokens used | Characters per file, or once on your own key |
Entry price, side by side
Lingo.dev charges a plan fee plus usage. Our monthly plans have the volume in the price.
| What | Lingo.dev | KAERIS |
|---|---|---|
| Cheapest paid plan | $99/mo (Production), plus usage | $19/mo (Pro), or $79 once |
| Free plan | Sandbox: $0 plus usage | 10,000 characters per file, no account |
| Pay once, no subscription | No | $79 Lifetime, on your own OpenRouter key |
Lingo.dev figures read from their pricing page on 25 October 2026, in the currency shown to us; prices change and theirs is the authority. Ours are on our pricing page.
When Lingo.dev is the better choice
You want a server-side engine with brand voice, glossary and model settings your team maintains.
You measure translation quality across many languages and models as a project of its own.
You prefer paying per token at their rates to a monthly volume.
What KAERIS does with it
A check with no key
kaeris checkruns on your machine, sends nothing and fails the build when a translation lost a variable or a key went missing.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.
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 configured engine your team maintains: Lingo.dev. A quick way to translate and check the files in your repo: KAERIS.