List of ~275,000 English words

Levenshtein edit distance. No cruft. Real fast.

AFINN 165 (list of English words rated for valence) in JSON

Formula to find the grade level according to the (revised) Dale–Chall Readability Formula (1995)

List of easy American-English words: The New Dale-Chall (1995)

Formula to detect the ease of reading a text according to the Gunning fog index (1952)

Formula to detect the ease of reading a text according to the Coleman-Liau index (1975)

Formula to detect the ease of reading a text according to the SMOG (Simple Measure of Gobbledygook) formula (1969)

Formula to detect the grade level of text according to the (revised) Spache Readability Formula (1974)

List of familiar American-English words: The Revised Spache (1974)