Deepl

What the Deepl MCP server does

The Deepl MCP server connects MCP-compatible agents to the DeepL API at https://api.deepl.com/v2 or its free-tier equivalent, https://api-free.deepl.com/v2. It provides translation, account usage, language discovery, and glossary compatibility checks.

Translation accepts one string or an array of strings. A caller can specify a target language such as EN-US, DE, JA, ES, or FR, and may optionally provide a source language. Additional translation controls cover sentence splitting, formatting preservation, formality, glossary selection, XML or HTML tag handling, and tag splitting or exclusion.

How it works

The Deepl MCP server can be reached through a Pipeworx MCP endpoint or started as a local package. The gateway route is https://gateway.pipeworx.io/deepl/mcp; the full gateway is also available at https://gateway.pipeworx.io/mcp. Both routes use the same underlying gateway and data sources, but the pack route lists the DeepL tools directly while also exposing shared Pipeworx meta-tools.

The local mode communicates over standard input and output. It serves only the DeepL pack tools and does not add the gateway's shared routing tools. Gateway users can also call tools over HTTP, including deepl_translate, and can pass a personal API key with the _apiKey argument.

Setup and configuration

For a gateway connection, add the MCP URL to the client configuration:

{
  "mcpServers": {
    "deepl": {
      "url": "https://gateway.pipeworx.io/deepl/mcp"
    }
  }
}

For standalone use, run the package with npx:

{
  "mcpServers": {
    "deepl": {
      "command": "npx",
      "args": ["-y", "@pipeworx/mcp-deepl"]
    }
  }
}

Authentication can use the platform variable PLATFORM_DEEPL_KEY or a caller-provided _apiKey. Keys ending in :fx are treated as free-tier keys and select the free DeepL endpoint automatically. Paid keys use the standard API endpoint.

Tools and capabilities

The Deepl MCP server exposes these pack-specific tools:

• translate translates one or more text values.
• usage returns the current month's character count and limit.
• source_languages lists supported source languages.
• target_languages lists supported target languages.
• glossary_language_pairs lists supported language pairs for glossaries.

The translate tool supports default, more, less, prefer_more, and prefer_less as formality values. Gateway connections also list shared Pipeworx tools, including discovery, search, memory, and cross-catalog question routing tools.

Limitations and notes

The shared Pipeworx key currently refuses translate requests with HTTP 456. The README reports that this is separate from the character quota: usage can show zero characters while translation remains unavailable. Use a personal DeepL key through _apiKey when gateway translation fails.

The integration is unofficial and is not affiliated with DeepL. The package is licensed under MIT. Gateway pack endpoints include shared meta-tools by design, so their tool list is larger than the five DeepL-specific tools. The standalone process avoids those additional gateway tools and routing behavior.