RhymeZone API
RhymeZone (rhymezone.com) has 2 public methods: get related words and get rhymes. Each costs 1 credit per completed run (1¢ with pay as you go); failed runs are free.
Unofficial. Not affiliated with or endorsed by RhymeZone.
Methods
2Finds words with similar meanings, opposite meanings, adjectives describing a word, or strongly associated words, ordered by relevance.
Returns word, part of speech, relevance score, RhymeZone page URL
Readrhymezone.com/get_related_wordsFinds perfect rhymes, near rhymes or similar-sounding words on RhymeZone, with syllable counts. Some matches may have no relevance score.
Returns word, syllables, relevance score, page URL
Readrhymezone.com/get_rhymes