Datamuse API

Base URL

https://api.datamuse.com

Authentication

No key for up to 100,000 requests per day.

Rate limit

100,000 requests per day without a key. Higher volumes require contacting the maintainer.

Pricing

Free at this volume, including commercial use.

CORS

Enabled — callable directly from browser JavaScript

Official docs

Read the docs

Every request below was executed against the live API on 19 Aug 2026, and the response shown is the real body it returned — not an illustration.

curl 'https://api.datamuse.com/words?rel_rhy=forest&max=5'

const res = await fetch("https://api.datamuse.com/words?rel_rhy=forest&max=5");
if (!res.ok) throw new Error(`Request failed: ${res.status}`);
const data = await res.json();
console.log(data);

import requests

res = requests.get("https://api.datamuse.com/words?rel_rhy=forest&max=5", timeout=20)
res.raise_for_status()
print(res.json())

[
  {
    "word": "florist",
    "score": 9033,
    "numSyllables": 2
  },
  {
    "word": "rainforest",
    "score": 3019,
    "numSyllables": 3
  },
  {
    "word": "reforest",
    "score": 23,
    "numSyllables": 3
  },
  {
    "word": "forrest",
    "score": 15,
    "numSyllables": 2
  },
  {
    "word": "deforrest",
    "score": 3,
    "numSyllables": 3
  }
]

[].wordstring

The suggested word.

[].scoreinteger

Relevance score; results are already sorted by it.

[].numSyllablesinteger

Syllable count, when requested via metadata.

[].tagsarray

Part-of-speech and pronunciation tags when metadata is requested.

• Build rhyme and synonym features for songwriting or poetry tools
• Power autocomplete and spelling suggestion in a search box
• Create crossword and word-game solvers with wildcard spelling queries
• Add thesaurus functionality to a writing application

If Datamuse does not fit, these book & dictionary apis cover similar ground. Every one was called before publishing, and each links to its own reference page with a working curl command and the response it returned.