Crowdin vs SYSTRAN Translate API

Crowdin

The REST API has a public OpenAPI document with 374 operations, and tokens can be limited by scope, access level and project. Translation runs inside Crowdin projects and connected engines, so it is not a stateless per-character translation API. No Retry-After guidance, idempotency keys or SLA were found in the reviewed documentation.

SYSTRAN Translate API

Five documented REST APIs cover text, files, dictionaries, translation memories and profiles, with a Google-compatible mode and a public price of €14.99 per million characters. The reference pages date from June 2023, and no changelog, status page, rate limit, SDK or downloadable OpenAPI file was found. The terms bar benchmark tests and automated use beyond human volumes.

Crowdin

1. Send Authorization: Bearer <token> to https://api.crowdin.com/api/v2. Crowdin Enterprise uses https://<organization_domain>.api.crowdin.com/api/v2
2. Use the MCP V2 endpoint https://mcp.crowdin.com/v2/mcp and set crowdin-tool-sets, because the server loads all 33 tool sets by default
3. Set crowdin-read-only: true on the MCP connection for exploration. It exposes only list and get tools
4. Keep to 20 concurrent requests an account across all tokens, and add your own backoff on 429
5. Upload a file to /storages first, then pass the storageId to the add-file call. Builds, exports and reports are asynchronous and need a status poll
6. /mts/{mtId}/translations takes at most 100 strings a call and needs the mt scope and a configured engine

SYSTRAN Translate API

1. Send the key as Authorization: Key <api_key> and avoid the documented ?key= query option, which puts the secret in URLs and logs
2. Expect HTTP 400, not 401, when credentials are missing. The body reads No key / credentials provided
3. Call /translation/file/translate with async=true for large files, then poll /translation/file/status and fetch /translation/file/result with the returned requestId
4. Apply dictionaries and translation memories through a profile and pass its UUID as profile. withDictionary and withCorpus are deprecated
5. Read the terms before automating. They bar benchmark tests and request volumes beyond normal human use, and SYSTRAN may throttle or suspend access