Big Huge Thesaurus


Get synonyms and antonyms from the Big Huge Thesaurus database

Get an API key

Base URL

GET /{API key}/{word}/{format}


Your private API key

The word you want to search


One of json, xml, or php. If format is omitted then the response will be plain text.


The response is always an array. The "php" format is a serialized PHP array that can be unserialized with the unserialize() function. The plain text response is pipe and newline delimited.

Relationship types are "syn" for synonyms, "ant" for antonyms, "rel" for related terms, "sim" for similar terms, and "usr" for user suggestions. Not all parts of speech or relationship types are guaranteed to be available for all words so test for their existence before using them.

Every API key comes with an admin page for monitoring and upgrade your key: Sample admin page

Example responses

Security and CORS

This server sends the Access-Control-Allow-Origin: * CORS header for all API requests. This allows you to use a JavaScript client in a web browser to make requests to the API. Please note that this is insecure and will allow anyone to see your API key. We strongly recommended that you use a server-side proxy to keep your key secret in all public clients.

HTTP Response Codes

Check the HTTP response code after every request. The response code will tell you if the request succeeded or if you need to take additional action.

200 OK The word was found and the results are in the body
303 {alternate} The original word was not found but an alternative has been. The alternative is the HTTP response message. For example, a request for "reminding" returns 303 remind. The Location header contains the URL for the API request for "remind."
404 Not Found No data could be found for the word or alternates
500 Usage Exceeded Usage limits have been exceeded
500 Inactive key The key is not active
500 Missing words No word was submitted
500 Not whitelisted The IP address was blocked

Please ensure that your application does not continue to make requests after you receive a "Usage exceeded" error until the following day (in GMT-8).

Third party API kits

These are wrappers for the Thesaurus API written by third parties. Send a link to your publicly hosted app or library if you'd like to include it on this page.

Plugins for other apps

Alfred App Logo SynAnt Alfred Workflow by vitorgalvao

Atom Editor Logo Thesaurus Atom Editor Plugin by Corwynt

Uptime status

Click to view the 7-day uptime status report


Get an API key