Glotto AI Translator

Glotto translates i18n JSON files (i18next, react-intl, vue-i18n, etc.) using AI providers without forcing the model to produce JSON. It walks the input JSON, extracts every string leaf with its path, sends them to the model as plain-text tagged batches, and reconstructs the JSON from the responses. The original structure, keys, arrays, variables and HTML tags are preserved by Glotto itself — the model only sees and produces text.

Installation

JSR (Deno)

deno install --global --name glotto -A jsr:@ibodev/glotto

Or run without installing:

deno run -A jsr:@ibodev/glotto

npm (Node)

npm install --global glotto

Or via npx:

npx glotto

pnpm

pnpm add --global glotto

Or via pnpx:

pnpx glotto

Usage

Basic (default OpenAI)

glotto --key <openai-api-key> -i en.json -o tr.json -f English -t Turkish

Gemini

glotto --key <gemini-api-key> -i en.json -o ar.json -f English -t Arabic -p gemini

OpenAI / OpenAI-compatible endpoints

glotto --key <openai-api-key> -i en.json -o tr.json -f English -t Turkish -p openai

Custom base URL (e.g. self-hosted OpenAI-compatible server):

glotto --key <key> -i en.json -o tr.json -f English -t Turkish \
  -p openai -m <model-name> --url <base-url>

Anthropic (Claude)

glotto --key <anthropic-api-key> -i en.json -o tr.json -f English -t Turkish -p anthropic

Override the model

glotto --key <key> -i en.json -o tr.json -f English -t Turkish -p openai -m <model-name>

Multi-target — translate to several languages in one run

Pass comma-separated values to -t/--to and -o/--output. The two lists must have the same length; entries pair up by index.

glotto --key <key> -i en.json -f English \
  -t "Turkish,French,German" \
  -o "tr.json,fr.json,de.json"

Incremental — translate only missing keys

When --incremental is set and the target file already exists, Glotto compares it against the source and only sends keys whose target value is missing or empty. The existing target structure is preserved; only the missing values are filled in.

glotto --key <key> -i en.json -o tr.json -f English -t Turkish --incremental

If the target file does not exist, Glotto falls back to a full translation.

Stats — see token usage

--stats prints input/output token totals, call counts, batch sizes and per-target breakdown after the run finishes. Off by default.

glotto --key <key> -i en.json -o tr.json -f English -t Turkish --stats

Config file (glotto.config.json)

You can keep flags in a config file so you don't have to retype them. Glotto looks for glotto.config.json in the current working directory by default; pass --config <path> to use a custom location. CLI flags always override config values.

Reference the JSON Schema for editor autocompletion and validation:

{
  "$schema": "https://raw.githubusercontent.com/ibodev1/glotto/main/schema/glotto.schema.json",
  "provider": "openai",
  "model": "gpt-4.1-mini",
  "input": "locales/en.json",
  "from": "English",
  "to": ["Turkish", "French", "German"],
  "output": ["locales/tr.json", "locales/fr.json", "locales/de.json"],
  "incremental": true,
  "stats": true
}

With this config you only need to provide the API key on the CLI:

glotto --key <key>

Disable rate-limit delay and request timeout

glotto --key <key> -i en.json -o tr.json -f English -t Turkish --no-limit --no-timeout

Tune batch size

--max-batch-size is the maximum source bytes per batch, in KB. Smaller batches mean more requests but lower per-request token cost; larger batches mean fewer requests.

glotto --key <key> -i en.json -o tr.json -f English -t Turkish --max-batch-size 8

Parameters

| Flag | Description | | ------------------ | ------------------------------------------------------------------------------------ | | --key | API key for the chosen provider (required) | | -p, --provider | gemini | openai | anthropic (default openai) | | -m, --model | Model name (defaults: gpt-4.1-mini, gemini-2.5-flash, claude-3-5-haiku-latest) | | -i, --input | Source JSON file (required) | | -o, --output | Target JSON file path. Comma-separated for multi-target (required) | | -f, --from | Source language | | -t, --to | Target language. Comma-separated for multi-target | | --url | Custom base URL for OpenAI/Anthropic | | --config | Path to a config file (default: ./glotto.config.json if present) | | --stats | Print AI usage stats (tokens, calls, bytes) at the end | | --incremental | Translate only missing/empty keys when the target already exists | | --no-limit | Skip the inter-batch rate-limit delay | | --no-timeout | Disable request timeout | | --max-batch-size | Max source bytes per batch in KB (default 12) | | -h, --help | Help | | -v, --version | Version |

Config file fields

glotto.config.json accepts the keys below. CLI flags override config values.

| Key | Type | Notes | | -------------- | ----------------------------------- | --------------------------------------- | | key | string | API key | | provider | openai | gemini | anthropic | | | model | string | | | input | string | Source JSON path | | from | string | Source language | | to | string | string[] | Single target or array for multi-target | | output | string | string[] | Must match to length when array | | url | string | Custom base URL | | noLimit | boolean | | | noTimeout | boolean | | | maxBatchSize | integer (KB) | | | stats | boolean | | | incremental | boolean | |

Development

Run from source:

deno task cli --key <key> -i en.json -o tr.json -f English -t Turkish

Build a single-file binary:

deno task build

Build npm package:

deno task build:npm

Star us

If Glotto saves you time, consider giving it a ⭐ on GitHub — it really helps the project reach more people.

License

MIT © 2026