About CHAIN
CHAIN is a daily word puzzle. Three chains a day — easy, medium and hard — and each one asks you to get from a start word to a goal word by filling in the words between, following the rule printed at every step.
There is no account, no sign-up and no fail state. Progress lives in your own browser and nowhere else.
Where the puzzles come from
Every puzzle is generated in advance and checked before it ships. The generator walks a graph of word relationships at random, discovers a chain, and then throws it away unless it survives a battery of quality checks. It is a lot more picky than it sounds: the bank of 500 days you are playing through was banked out of roughly a quarter of a million attempts.
Everything is verified with the same code that runs in your browser, so the game can never hand you a puzzle it would refuse to let you solve. Every banked chain is then replayed link by link by a separate test before it is published, which exists to catch the generator being wrong rather than to trust it.
Why the rules are what they are
A rule earns its place by being checkable and by being fair to guess at. Those pull in different directions, and most of the design is about the tension between them.
Compound is the heart of the game and the hardest to get right, because "do these two words go together" is a question about meaning and no word list answers it. The compound pairs are hand-curated, and the joined word has to be one people actually use — the dictionary happily calls INKWELL, GUARDDOG and OFFPEAK words, and none of them belongs as the answer to a daily puzzle.
Swap ends replaced an earlier rule that asked whether two words formed a phrase. That rule was renamed three times in a day trying to describe a category that kept not existing: EASY WAY is a phrase, BLACK HOLE is not an idiom, and players kept typing real English and being refused. Swap ends has no judgement in it at all. The answer starts with the letter the previous word ended on. There is nothing to argue about.
Rhyme and homophone are read from a public phonetic dictionary rather than matched by spelling, which is why DAY and BOUQUET count and COUGH and BOUGH do not.
What the game deliberately doesn't do
It never tells you that you are wrong. A word that doesn't fit is simply not accepted, and the message says which part of the rule it missed rather than scoring you on it.
It doesn't track you. There are no analytics, no cookies set by the game, and no account to attach anything to. The privacy page describes exactly what is stored, which is your progress, in your browser.
It doesn't spoil itself. The share card shows the rules you solved as coloured squares and never the words you used, so a posted result is safe to read before you have played.
It doesn't rank you against anyone. There is no leaderboard and no score. Three chains, closed or not closed, and new ones tomorrow.
Accessibility and support
The board is keyboard-navigable: tab moves between the word boxes and nothing else, so a chain can be filled in without a mouse. The game respects your system's dark mode, and honours a reduced-motion preference by skipping the animations entirely.
It runs in any current browser and needs no installation. It works on a phone, and it works offline once loaded, because the whole puzzle bank is downloaded with the page.
Contact
Found a word the game should accept and doesn't? That is the most useful thing you can report, and most of the dictionary work so far has come from exactly those messages — [email protected].