Wiktionary vs Wordnik

Wiktionary exposes its full multilingual dictionary — definitions, etymologies, pronunciations, and translations spanning thousands of languages — through the same MediaWiki Action API that powers Wikipedia, with no key required for read access. Cross-origin browser requests need the documented origin=* query parameter rather than a bare Origin header, since that's what actually unlocks the API's CORS headers.

Wordnik's REST API returns word definitions aggregated from multiple published dictionaries alongside example sentences, pronunciations, related words, and corpus-derived frequency data, documented through an interactive Swagger UI. Every developer gets a free Basic plan (100 calls/hour, with an explicit nonprofit/research allowance) before paid Hobby, Pro, and Enterprise tiers raise the ceiling up to 45,000 calls/hour -- revenue that funds Wordnik's nonprofit mission to document the English language.