DeepL MCP Server

deepl-mcp-server

[!NOTE] For the best experience and the latest features check out the DeepL remote MCP server to use DeepL in your AI agent. No installation required, just add it to Claude, ChatGPT, Microsoft Copilot or any MCP client and sign in with your DeepL account.

Working in a terminal or with a coding agent? Try the DeepL CLI. It covers translation, documents, glossaries and i18n file sync with your API key.

A Model Context Protocol (MCP) server that exposes DeepL text translation, document translation, rephrasing, and glossary and style rule lookups as MCP tools.

Usage

You need Node.js 18 or newer and a DeepL API key. Pick an API plan and create a key in your DeepL account.

The server communicates over stdio, so it is normally started by an MCP client rather than by hand. To try it directly:

DEEPL_API_KEY=your-api-key npx -y deepl-mcp-server

It exits immediately if DEEPL_API_KEY is not set.

To work on the server itself:

git clone https://github.com/DeepL/deepl-mcp-server.git
cd deepl-mcp-server
npm install

Configuration

Register it as a stdio server with DEEPL_API_KEY in the server's environment. In Claude Code:

claude mcp add deepl --env DEEPL_API_KEY=your-api-key -- npx -y deepl-mcp-server

For clients configured through a JSON file:

{
  "mcpServers": {
    "deepl": {
      "command": "npx",
      "args": ["-y", "deepl-mcp-server"],
      "env": {
        "DEEPL_API_KEY": "your-api-key"
      }
    }
  }
}

Where that file lives and how each client expects local stdio servers to be declared:

• Claude Code
• Claude Desktop
• Cursor
• VS Code

To run a local checkout instead of the published package, use node as the command and the absolute path to src/index.mjs as the argument.

Tools

Tool	Description	Parameters
translate-text	Translates text into a target language.	text, targetLangCode, sourceLangCode?, formality?, glossaryId?, styleId?, context?, preserveFormatting?, splitSentences?, customInstructions?
translate-document	Translates a document file (PDF, DOCX, PPTX, XLSX, HTML, TXT, and more) and writes the result to disk.	inputFile, targetLangCode, outputFile?, sourceLangCode?, formality?, glossaryId?, styleId?, outputFormat?
rephrase-text	Rephrases text, optionally into another language.	text, targetLangCode?, style?, tone?
get-source-languages	Lists the language codes accepted as a translation source.	none
get-target-languages	Lists the language codes accepted as a translation target.	none
get-writing-styles	Lists the style values rephrase-text accepts.	none
get-writing-tones	Lists the tone values rephrase-text accepts.	none
list-glossaries	Lists every glossary in the account with its id, name, dictionaries, and creation time.	none
get-glossary-info	Returns the same metadata as list-glossaries for a single glossary.	glossaryId
get-glossary-dictionary-entries	Returns the term entries of one glossary dictionary, meaning one language pair in one direction.	glossaryId, sourceLangCode, targetLangCode
list-style-rules	Lists the style rules in the account with their id, name, language, and timestamps.	page?, pageSize?, detailed?
get-style-rule	Returns one style rule in full, including its configured rules and custom instructions.	styleId
get-custom-instruction	Returns a single custom instruction belonging to a style rule.	styleId, instructionId

Notes:

• text takes either a single string or an array of strings. Each entry is translated or rephrased independently.
• Language codes are ISO 639-1, optionally with a region (en-US). Omitting sourceLangCode triggers automatic detection. A target code whose language requires a region gets a default applied: en becomes en-US, pt becomes pt-BR, zh becomes zh-Hans.
• Glossary dictionaries are keyed by non-regional codes, so get-glossary-dictionary-entries drops any region you pass.
• Translating with a glossary requires an explicit sourceLangCode.
• formality accepts less, more, default, prefer_less, and prefer_more. The prefer_* values fall back to the default when the target language has no formality support.
• translate-document reads and writes files on the machine running the server. Without outputFile, the output path is derived from the input by appending the target language code, for example report_de.pdf. With outputFormat, the derived path uses that extension instead.
• Style rules and custom instructions are read-only here. Create and edit them in your DeepL account.

License

MIT