Datamuse

Datamuse operates a word-finding query engine and lexical search service for developers, educators, and creative-writing applications. The Datamuse API exposes a /words endpoint that finds words matching a rich combination of semantic, phonetic, orthographic, and vocabulary constraints (means-like, sounds-like, spelled-like, synonyms, antonyms, hypernyms, meronyms, triggers, rhymes, homophones, and more) plus a /sug autocomplete endpoint. Free for non-commercial use up to 100,000 requests per day with no API key required; commercial use, custom vocabularies, and higher rate limits are available via a paid commercial agreement.

Datamuse also runs OneLook, OneLook Thesaurus, RhymeZone, Rimar.io, and CivicSearch — consumer-facing word-search tools built on the same lexical infrastructure.

• APIs.yml: apis.yml
• Website: https://www.datamuse.com/
• Documentation: https://www.datamuse.com/api/
• API Reference: https://www.datamuse.com/api/

Type and Tier

• x-type: company
• x-tier: 3 (bulk-registered from public-apis)
• Source: public-apis/public-apis — category: Open Source Projects

API Surface

Method	Endpoint	Summary	Min Plan
GET	/words	Find Words Matching Constraints	Free Non-Commercial
GET	/sug	Get Autocomplete Suggestions	Free Non-Commercial

Base URL: https://api.datamuse.com · Auth: none (no API key required).

Query Parameters at a Glance

Family	Parameters	Purpose
Semantic	ml, rel_syn, rel_ant, rel_trg, rel_spc, rel_gen, rel_com, rel_par, rel_jja, rel_jjb	Reverse-dictionary, synonyms, antonyms, hypernyms, hyponyms, holonyms, meronyms, triggers, adjective-noun pairings
Phonetic	sl, rel_rhy, rel_nry, rel_hom, rel_cns	Sounds like, perfect rhymes, near rhymes, homophones, consonant matches
Orthographic	sp	Wildcard spelling patterns (*, ?)
Statistical	rel_bga, rel_bgb	Frequent followers / predecessors per Google Books Ngrams
Context	topics, lc, rc	Document topics, left context word, right context word
Result control	max, md, qe, ipa	Result size, metadata flags (d/p/s/r/f), query echo, IPA pronunciations
Vocabulary	v	en (default, 550k terms), es (500k terms), or custom
Autocomplete (/sug)	s, max, v	Prefix string, max results, vocabulary

Artifacts

Contract

• openapi/datamuse-openapi.yml — full OpenAPI 3.1 contract for /words and /sug with every documented query parameter.

Schemas

• json-schema/datamuse-word-schema.json — /words response object.
• json-schema/datamuse-suggestion-schema.json — /sug response object.

JSON Structure

• json-structure/datamuse-word-structure.json
• json-structure/datamuse-suggestion-structure.json

JSON-LD Context

• json-ld/datamuse-context.jsonld — maps Datamuse word objects onto OntoLex, SKOS, and LexInfo vocabularies.

Examples

• examples/datamuse-getwords-example.json — reverse-dictionary lookup with metadata.
• examples/datamuse-getsuggestions-example.json — autocomplete with spelling correction.

Spectral Rules

• rules/datamuse-rules.yml — enforces operationId, Title Case summaries, snake_case query parameters, HTTPS servers, and 429 documentation.

Naftiko Capabilities

• capabilities/shared/datamuse-shared.yaml — per-API operation primitives.
• capabilities/word-discovery.yaml — combined semantic-relation discovery.
• capabilities/rhyme-and-phonetics.yaml — rhymes, near rhymes, homophones, sounds-like.
• capabilities/reverse-dictionary.yaml — tip-of-the-tongue lookup with optional spelling hint.
• capabilities/autocomplete.yaml — type-ahead suggestions with spelling correction.

Vocabulary

• vocabulary/datamuse-vocabulary.yml — resources, endpoints, constraints, relations, ranking hints, metadata flags, vocabularies, plans, capabilities.

Commercial & FinOps

• plans/datamuse-plans-pricing.yml — Free Non-Commercial (100k req/day, no key) and Commercial (negotiated).
• rate-limits/datamuse-rate-limits.yml — per-IP 100k/day on the free tier; commercial quotas negotiated.
• finops/datamuse-finops.yml — FOCUS mapping, allocation tags, optimization plays (caching, debouncing, scoping with max).

Plan and Feature Gating

Plan	Price	Quota	Custom Vocab	API Key	Commercial Use	SLA
Free Non-Commercial	$0	100,000 req/day	No	No	No	No
Commercial	Negotiated	Negotiated	Yes	Optional	Yes	Per contract

To arrange commercial use, custom vocabularies, or elevated rate limits, contact Datamuse via the link on the API documentation page.

Community SDKs

Datamuse does not maintain an official GitHub organization; the community has published wrappers in many languages:

Language	Repository
Java	sjblair/Datamuse4J
Python	gmarmstrong/python-datamuse
Node.js	ansteh/datamuse
Swift	ezefranca/datamuse-swift
PHP	owenvoke/datamuse-php-api-wrapper
Go	kostaspt/go-datamuse
Rust	slogemann1/datamuse-api-wrapper
.NET	benhess02/DatamuseDotNet
Ruby	mosegontar/rubymuse

MCP Servers and AI Tooling

Multiple community Model Context Protocol servers expose the Datamuse API to LLM agents:

• lacausecrypto/datamuse-mcp
• pipeworx-io/mcp-datamuse
• bhayanak/datamuse-mcp-server — 12+ word-finding tools.
• pipeworx-io/mcp-words
• Eyalm321/multilingual-dictionary-mcp — combines Datamuse with ConceptNet and Wiktionary.

Tags

Word Finding, Lexical Search, Natural Language, Vocabulary, Synonyms, Antonyms, Rhymes, Phonetics, Semantic Search, Reverse Dictionary, Autocomplete, Wordplay, Creative Writing, Vocabulary Apps, Word Games, Linguistics, Open Source Projects, Public APIs

Timestamps

• Created: 2026-05-28
• Modified: 2026-05-29

Maintainers

• Kin Lane — kin@apievangelist.com