The Linguin API is live. One key, one POST per call, JSON in and out, 120+ languages.
Three methods:
Translation bills by the word, never for whitespace or punctuation. Add Live to cross-check the wording against real usage on the web, add Humanizer to make the output read like a person wrote it.
Dictionary is quick: a fast lookup for the definition, or a deep one for the full entry with senses, examples, and etymology.
Prepaid, with free credit to start and every charge shown on the response. Full pricing is on the API page.
Grab a key on the pricing page and start with the docs.