A solver earns its name when you're working from partial information — some letters certain, some unknown, and constraints on where things go. Enter the letters you have, stand in for up to two unknowns with question marks (?), and narrow the results with the length, starts-with, ends-with, and contains filters until only the words that fit your puzzle remain. Every result is a real dictionary word, ranked by game points, with a definition one click away.
A worked example: you're sure a five-letter answer starts with T and contains R and A, but two letters are a mystery. Enter T, R, A and two wildcards, set the length to five and "starts with" to T — the solver returns TRACK, TRAIL, TRAWL, TREAT, and the rest of the candidates in one pass, turning a staring contest into a shortlist. The same mechanics cover the rack-based games: for a straight tile jumble with no constraints, the word descrambler guide walks through every filter in detail.
Crosswords and fill-ins — the natural habitat. When crossing words have given you most of a answer's letters, the wildcard-plus-filters search closes the gap. (What it can't do: interpret the clue — see the FAQ below for where the line sits.)
Jumbles and letter puzzles — enter the scrambled letters plainly and the full word list comes back; the Jumble solver adds the newspaper puzzle's specific format.
Post-game analysis — the honest competitive use, same as everywhere on this site: run finished racks from Scrabble or Words with Friends matches to see what you missed. Mid-tournament use is against the rules of any rated event, and the solver's real competitive value is making your next unaided game better.
Learning and teaching — the definition-click turns every search into a vocabulary stop, and teachers use constraint searches to build word lists for spelling patterns ("five letters, ends in -CK") faster than any workbook index.
House-rules game night — some tables play "solver allowed, placement is on you," which keeps younger or newer players competitive with word-hoarding relatives. Agree on it up front and the tool becomes a handicapping system rather than a controversy.