DeepL MCP Server

What is DeepL MCP Server?

An MCP (Model Context Protocol) server that provides high‑quality translation capabilities via the DeepL API, for use with MCP clients like Claude Desktop and Claude Code. It offers 24 tools covering text translation, rephrasing, document translation, glossary management, translation memories, style rules, voice sessions, and usage statistics.

How to use DeepL MCP Server?

Install Node.js 18+, clone the repository, run npm install, build with npm run build, then configure your MCP client with the server command pointing to the built index.js and set the DEEPL_API_KEY environment variable. For example, in Claude Desktop’s configuration JSON add a “deepl” MCP server entry with the command node and args ["/path/to/deepl-mcp-server/build/index.js"] plus the env variable. Restart the client to load the server.

Key features of DeepL MCP Server

• 24 tools including translation, rephrasing, document upload, glossaries, voice sessions
• Automatic detection of Free vs Pro API from the key suffix (:fx or not)
• Supports next‑gen model selection, formality, context, glossaries, and batch translation
• Document translation: upload, check status, download translated files
• Voice session setup via DeepL Voice realtime WebSocket
• Comprehensive error handling for common API errors (400, 401/403, 429, 456)

Use cases of DeepL MCP Server

• Translate text with control over formality, model, glossaries, and tag handling
• Rephrase text to improve clarity and style using DeepL Write options
• Manage glossaries (create, list, inspect, delete) and translation memories
• Upload and download translated documents automatically
• Integrate real‑time translation into voice‑enabled applications

FAQ from DeepL MCP Server

What runtime and API key are required?

Node.js 18+ and a DeepL API key from the Free or Pro API. The server automatically picks the correct API endpoint based on the key format: keys ending in :fx use api‑free.deepl.com, others use api‑pro.deepl.com.

How do I configure my MCP client?

Add a JSON entry under "mcpServers" with the command node, args pointing to the built index.js, and an env object containing "DEEPL_API_KEY". Examples for Claude Desktop and Claude Code are in the README.

What languages are supported?

29 source languages (auto‑detected if omitted) and target languages including regional variants (e.g., EN‑GB, EN‑US, PT‑BR, ZH‑HANS). Use get_target_languages for a full list with formality support info.

How does the server handle API errors?

It returns error messages for HTTP statuses 400 (invalid parameters), 401/403 (authentication/plan limits), 429 (rate limit), and 456 (quota exceeded). The server also reports usage statistics via the get_usage tool.

What are the main limitations of the Free API?

Free API keys may return an expected plan error for DeepL Write. Quota limits apply (visible via get_usage), and certain features like glossaries or style rules might be restricted depending on the plan.