Dictionaries · head-to-head
Free Dictionary vs Wiktionary
Free Dictionary API is a keyless REST service built and maintained by a solo developer, returning English word definitions, phonetic spellings, audio pronunciation clips, parts of speech, usage examples, and synonyms/antonyms as plain JSON from a single GET request. It now serves more than 10 million requests a month and is funded entirely through voluntary donations rather than any paid tier.
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.
| Free Dictionary | Wiktionary | |
|---|---|---|
| Authentication | None | None |
| Pricing | free | free |
| Formats | JSON | JSON, XML |
| CORS | yes | yes |
| HTTPS | Yes | Yes |
Wiktionary supports 2 response formats, while Free Dictionary offers fewer — pick Wiktionary for more integration flexibility.