Thesaurus API

Free · Livelanguage

Synonyms, antonyms, and related words for English, built from Open English WordNet (CC BY 4.0) and the public-domain Moby Thesaurus.

https://api.gargantuan.dev/v1/thesaurusFull reference →

Quick start

No key needed. Try a request right now:

Request
curl "https://api.gargantuan.dev/v1/thesaurus/languages"

Or open it in your browser: https://api.gargantuan.dev/v1/thesaurus/languages

Authentication & limits

No key required. Anonymous callers are rate-limited by IP. Send Authorization: Bearer <key> (or an X-Api-Key header) for a higher tier.

With a key (higher tier)
curl "https://api.gargantuan.dev/v1/thesaurus/languages" \
  -H "Authorization: Bearer YOUR_API_KEY"

Also accepts X-Api-Key or ?api_key=. Limits ride in X-RateLimit-* headers; over the limit returns 429. See rate limits.

Datasets

Pick one with ?lang= (or the relevant param). 1 available:

DatasetCodeLocaleEntries
Englishenen131,753

Endpoints

Edit the inputs and hit Send request to try any endpoint live, right here. No key needed.

GET/v1/thesaurus/languages

List the supported languages (datasets).

Request
https://api.gargantuan.dev/v1/thesaurus/languages
GET/v1/thesaurus/random

Return a random word with its synonyms, antonyms, and related terms.

Request
https://api.gargantuan.dev/v1/thesaurus/random?lang=en
GET/v1/thesaurus/search

Autocomplete: words that start with a prefix.

Request
https://api.gargantuan.dev/v1/thesaurus/search?q=hap&limit=5&lang=en
GET/v1/thesaurus/synonyms/{word}

Synonyms of a word.

Request
https://api.gargantuan.dev/v1/thesaurus/synonyms/happy?lang=en
GET/v1/thesaurus/antonyms/{word}

Antonyms of a word.

Request
https://api.gargantuan.dev/v1/thesaurus/antonyms/happy?lang=en
GET/v1/thesaurus/related/{word}

Related words (broad coverage, from Moby).

Request
https://api.gargantuan.dev/v1/thesaurus/related/happy?lang=en
GET/v1/thesaurus/{word}

Full entry: synonyms, antonyms, related words, and per-sense definitions.

Request
https://api.gargantuan.dev/v1/thesaurus/serendipitous?lang=en

FAQ

Is the Thesaurus API free to use?

Yes. It is free and public. Anonymous requests need no key and are rate-limited by IP; a free API key raises your limits.

Do I need an API key?

No key is required to start. Send an Authorization: Bearer key (or an X-Api-Key header, or ?api_key=) to move to a higher tier.

What is the base URL?

https://api.gargantuan.dev/v1/thesaurus

What are the rate limits?

Every response carries X-RateLimit-Limit and X-RateLimit-Remaining headers. Anonymous callers get the lowest tier (by IP); a free key is higher; Pro is highest. Over the limit returns 429 with Retry-After.

What format does it return?

JSON over HTTPS. Every response also includes a "source": "itsmattgeorge.com" attribution field.

Full reference & authentication
Params, live responses, keys, and every endpoint in one place.
Open the docs →