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dptran is a command-line tool and library for using the DeepL API, written in Rust.

• Translate via CLI, interactive input, pipeline, or file/editor input
• Support for multi-line input, output to file, and removing line breaks
• DeepL API Free / Pro support
• Language code lookup and character usage tracking
• Result caching

• API client for DeepL translation
• Language code and usage queries

cargo install dptran

dptran includes dependencies for the binary CLI by default. To use only the library, please disable default features.

cargo add dptran --no-default-features

dptran api --api-key-free [Your API key]
# or set env: export DPTRAN_DEEPL_API_KEY=[Your API key]

If you want to use DeepL Pro API key, set it like this:

dptran api --api-key-pro [Your API key]
# or set env: export DPTRAN_DEEPL_API_KEY_PRO=[Your API key]

# simple translation (translate to default target language)
dptran Hello
こんにちは

# translate with target language
dptran -t FR Hello
Bonjour

# translate with source language
dptran -f EN -t JA Hello
こんにちは

# translate interactively (original text is not given at startup)
dptran -t JA
> Hello
こんにちは
> /to FR   # Change target language to French
> Hello
Bonjour
> /quit    # To exit interactive mode

# translate from a file and output to another file
dptran -i text.txt -o translated.txt
# The file `translated.txt` will contain the translated text.

# translate with a pipeline
echo "Hello" | dptran -t ZH
您好

# translate with line breaks removed
dptran -r "Hello
everyone!"
皆さん、こんにちは！

# translate from an editor (like vim, emacs. must be set in config)
dptran -e
# Editor will open

• -t [LANG] Set the default target language
• -f [LANG] Set the default source language
• -i [FILE] Input from file
• -o [FILE] Output to file
• -r Remove line breaks
• -u Show character usage

For more options and detailed usage, run:

dptran -h

• list : Show list of supported languages (-s for source languages, -t for target languages)
• config : General settings such as default target language and editor command
• api : API settings such as API keys and endpoint URLs
• cache : Cache settings such as enabling/disabling cache, setting max entries, and clearing cache
• help : Print this message or the help of the given subcommand(s)

Change default target language:

dptran config --target-lang JA

Reset all settings:

dptran config --clear-all

You can set the API endpoint URL using the api subcommand:

dptran api --endpoint-of-translation <ENDPOINT_OF_TRANSLATION>
dptran api --endpoint-of-usage <ENDPOINT_OF_USAGE>
dptran api --endpoint-of-langs <ENDPOINT_OF_LANGUAGES>

Then you can use dptran with your own API endpoint, e.g., a local LLM server.
Note that the API endpoints must be compatible with the DeepL API specification.

Run unit tests. To run tests that require a real DeepL API key, set the environment variable DPTRAN_DEEPL_API_KEY:

export DPTRAN_DEEPL_API_KEY=[API key]
cargo test -- --test-threads=1

Some require dummy API server to be running.
The dummey server will be run at http://localhost:8000/ by default.

$ pip3 install -r requirements.txt
$ uvicorn dummy-api-server:app --reload

Crate page: https://crates.io/crates/dptran

Library docs: https://docs.rs/dptran

Licensed under either of:

• MIT License
• Apache License 2.0

• v2.3.4 (2025-10-04)

  • Binary CLI: Support inputting commands in interactive mode (/quit, /help, /from, /to, etc.)

• v2.3.3 (2025-09-07)

  • Binary CLI: Add clear-all and show options to API settings, change config --clear-all to not reset these API settings
  • Binary CLI: Improve error handling in do_translation()
  • Library: Modularize each API implementation in translate, languages, and usage

• v2.3.2 (2025-07-07)

  • Binary CLI: Fix issue where endpoint settings were not reflected in usage and lang commands
  • Library: Fix query encoding when sending requests

• v2.3.1 (2025-07-01)

  • Binary CLI & Library: Any api endpoint can be used
  • Binary CLI: Split set subcommand into config, api, and cache subcommands
  • Test: Use the python dummy API server for some tests