Free APIKnowledgeNo keyOfficial
Datamuse API
Word-finding engine: rhymes, synonyms, autocomplete and context, no key (until 2027)
Datamuse is a word-finding query engine for developers: find words by meaning, sound, spelling pattern, or words that fit a given context. The /words endpoint applies constraints (means-like, sounds-like, rhymes, follows a word) and /sug powers autocomplete. No key is required today.
Free tier
Free, no key, up to 100,000 requests/day until 1 Jan 2027 (a still-free API key will be required after that)Rate limits
100,000 requests/day; beyond that requests may be throttled without noticeAuth
No keyBase URL
https://api.datamuse.comWhat you'd build with it
- Build a thesaurus, rhyme or autocomplete feature
- Generate constrained word lists for puzzle or naming tools
- Suggest contextually fitting words inside a writing assistant
- Expand keywords for search-query generation
Key endpoints
- GET
/words?ml={word}Words with a meaning like the query - GET
/words?rel_rhy={word}Words that rhyme with the query - GET
/words?sp={pattern}Words matching a spelling/wildcard pattern - GET
/sug?s={prefix}Autocomplete suggestions for a prefix
Members
Members get the runnable recipe
Sign in free to copy the example request, see a sample response, and read the gotchas.
Tags
knowledgelanguagewordsnlpreference