The paint matcher is a free, no account tool that takes a list of the paints you already own and finds the closest equivalent in every other brand, so when a recipe calls for a colour you do not have you can see what you can use instead without buying a whole new range. You paste your paints in, one per line with the brand first, and it does the rest against the catalogue.
It matches on real colour science rather than a name lookup, using the CIEDE2000 perceptual distance so the equivalent it gives you is genuinely the nearest colour a human eye would agree on, not just something with a similar name on the pot. Every match comes with an honest grade, excellent, good or acceptable, and I do not show you anything below that, because a bad match dressed up as a good one is worse than no match at all.
Each colour also carries where its data came from, whether it is an official swatch from the maker or built from the catalogue, so you can see how much to trust a given match instead of taking it on faith. Anything that does not have a clean match gets listed on its own rather than fudged. It is one of the tools that works with no sign in at all, and it feeds the scheme planner and shopping side of the app so the paints you are told to buy are the closest ones you can actually get.