Polytranslator API

Document translation API that keeps the layout. Send a PDF (including scans), Word, PowerPoint, Excel, EPUB or a photo, and get the same kind of file back translated into any of 474+ languages, including ancient and low-resource languages that DeepL, Google, Azure and Amazon do not offer (Ancient Greek, Coptic, Old English, Old Norse, Aramaic, Akkadian, Sumerian and more). Text translation, webhooks and a remote MCP server for AI agents use the same API key and prepaid credits. No subscription.

• Website and pricing: https://www.polytranslator.com/developers/
• Full reference: https://www.polytranslator.com/developers/docs/ (Markdown for agents: https://www.polytranslator.com/api.md)
• OpenAPI: openapi.json (live at https://www.polytranslator.com/api/openapi.json)
• MCP server: https://www.polytranslator.com/api/mcp
• Get an API key: https://www.polytranslator.com/api-keys/

Quickstart

export POLYTRANSLATOR_API_KEY=pk_live_...

# 1. Submit (returns 202 with a document id)
curl https://www.polytranslator.com/api/v1/documents \
  -H "Authorization: Bearer $POLYTRANSLATOR_API_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -F file=@contract.pdf -F tgt=spa_Latn

# 2. Wait (the request is held open until the document finishes, up to 60 s)
curl "https://www.polytranslator.com/api/v1/documents/$DOCUMENT_ID?wait=60" \
  -H "Authorization: Bearer $POLYTRANSLATOR_API_KEY"

# 3. Download the translated file, same format and layout
curl -OJ https://www.polytranslator.com/api/v1/documents/$DOCUMENT_ID/file \
  -H "Authorization: Bearer $POLYTRANSLATOR_API_KEY"

Runnable examples:

Task	Python	Node	curl
Translate a document	translate_document.py	translate-document.mjs	translate-document.sh
Free quote	quote_document.py
Translate text	translate_text.py
Verify a webhook	verify_webhook.py	verify-webhook.mjs

What it does

Formats in	PDF (text-based or scanned), DOCX, PPTX, XLSX, EPUB, PNG, JPG, WEBP, HEIC; DOC, ODT, RTF, TXT, Markdown, HTML, XML, SRT, VTT, TeX, Pages → DOCX; XLS, ODS, CSV, TSV, Numbers → XLSX; PPT, ODP, Keynote → PPTX; MOBI, AZW3, FB2 → DOCX
Output	The same file type with layout, tables and images preserved; text in scans and photos is translated in place (output=formatted). Or translated text only (output=text).
Limits	50 MB, 1,000 PDF pages, 1,000,000 characters per document; 5 documents in progress per account
Languages	474+, source auto-detected; GET /v1/languages
Tiers	fast and advanced (the most accurate)
Price	Prepaid credit packs from $9.99 (300 credits) to $99.99 (5,000). Every document is quoted for free before you pay and charged exactly its quote; failed documents are refunded. Text: 1 credit per 1,000 characters (fast), 3 (advanced).
Async	?wait= long-poll, or a signed webhook (callback_url) when the document finishes
Safety	Idempotency-Key on submissions (a retry never charges twice), max_credits spending cap per request
Agents	Headless signup and purchase with a Stripe Shared Payment Token, OpenAPI, llms.txt, remote MCP server

Measured examples on the fast tier: a short Word contract costs 1 credit; a one-page scanned court filing costs 19 credits.

Use it from AI agents (MCP)

Remote Streamable HTTP server, nothing to install. Tools: translate_document, get_document, quote_document, translate_text, list_languages, get_credit_balance. Completed documents come back as download links that work without a key for 24 hours.

Claude Code

claude mcp add --transport http polytranslator https://www.polytranslator.com/api/mcp \
  --header "Authorization: Bearer $POLYTRANSLATOR_API_KEY"

Cursor / Windsurf (.cursor/mcp.json)

{
  "mcpServers": {
    "polytranslator": {
      "url": "https://www.polytranslator.com/api/mcp",
      "headers": { "Authorization": "Bearer YOUR_API_KEY" }
    }
  }
}

VS Code (.vscode/mcp.json)

{
  "servers": {
    "polytranslator": {
      "type": "http",
      "url": "https://www.polytranslator.com/api/mcp",
      "headers": { "Authorization": "Bearer YOUR_API_KEY" }
    }
  }
}

Codex (~/.codex/config.toml)

[mcp_servers.polytranslator]
url = "https://www.polytranslator.com/api/mcp"
bearer_token_env_var = "POLYTRANSLATOR_API_KEY"

Registry entry: mcp/server.json (com.polytranslator/translator).

How it compares

A sourced comparison with DeepL, Google Cloud Translation, Azure AI Translator and Amazon Translate (formats, scans, limits, languages, pricing, minimum charges, setup) is at https://www.polytranslator.com/guides/document-translation-api/.

Postman

Import postman/polytranslator.postman_collection.json and set the apiKey collection variable to your API key.

About

Polytranslator is built by the authors of From LLM to NMT: Advancing Low-Resource Machine Translation with Claude (Enis & Hopkins, 2024, arXiv:2404.13813). Questions: support@polytranslator.com.

The examples in this repository are MIT licensed.