# Datamuse

**Canonical:** https://apis.io/providers/datamuse/  
**Website:** https://www.datamuse.com/  
**APIs profiled:** 2

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.

## Kin Score — 46.9 / 100 (developing)

Scored 2026-08-20 under rubric 0.12.0. Trend: flat (+0.0 from 46.9).

| Facet | Score |
|---|---|
| Discoverability | 75.9 |
| Contract Quality | 66.4 |
| Governance | 25.0 |
| Contract Governance | 25.0 |
| Operational Transparency | 0.0 |
| Developer Ergonomics | 38.1 |
| Commercial Clarity | 60.5 |
| Access Clarity | 60.5 |

## Agent readiness — 24.5 (agent-aware)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | derived |
| Reversibility Documented | na |
| MCP Server | no |
| Auth Clarity | no |
| Idempotency | na |
| Error Semantics | no |
| OpenAPI Examples | no |
| Rate Limit Signal | documented |
| Event Surface Described | no |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | na |

## Access

Freemium · Open access — onboarding: open, pricing: freemium, trial: no (confidence: medium).

## APIs (2)

- **Datamuse Suggestions API** — Autocomplete suggestions with spelling correction and semantic fallback.
- **Datamuse Words API** — Word-finding queries combining semantic, phonetic, orthographic, and vocabulary constraints.

## Agentic access (1)

- **Datamuse Agentic Access** — 2 operations

## Security (1)

- **Datamuse Domain Security** — TLSv1.2 · DMARC

## Plans (1)

- **Datamuse Plans Pricing**

## Use cases (8)

- **Vocabulary Building Apps** — Power flashcards, quizzes, and language-learning apps with synonyms, antonyms, and related-word lookups.
- **Creative Writing Tools** — Drive rhyme finders, thesaurus add-ins, and reverse-dictionary lookups for poetry, songwriting, and copywriting.
- **Word Games and Puzzles** — Generate clues, fill patterns with sp wildcards, and validate word lists for crosswords, hangman, and word ladders.
- **Autocomplete and Type-Ahead** — Provide intelligent prefix suggestions with spelling correction in search bars and form fields.
- **Educational Software** — Add definitions, syllable counts, and pronunciations to reading apps, ESL tools, and accessibility software.
- **Search Query Expansion** — Expand a user's search terms with semantically related words to improve recall in document or product search.
- **NLP Pre-Processing** — Look up word relations, frequencies, and pronunciations as features for downstream NLP pipelines.
- **Brand and Product Naming** — Combine sounds-like, means-like, and spelled-like constraints to brainstorm brand, domain, or product names.

## 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

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/datamuse/). Scores are computed from the provider's own public artifacts under a published rubric.