About
Confluence is intended to be a hub for Magic: The Gathering deckbuilding. Our first tool is Land Calculator, a probability-backed land recommendation system.
The land calculator
The goal is a cheaper land base that's as good as your current one or better. Paste in your commander decklist and it plays thousands of simulated games, using real versions of most of the lands people typically play in commander, then tells you which lands to change.
You get a castability percentage for the deck now and after its recommended adds and swaps, plus what you'd save, since every swap is priced against the land it replaces. A typical result will both increase castability and save you money.
Where it works
It's built for casual commander decks (bracket 3 and below). It looks at your first 8 turns, so it's pretty useless for cEDH, where games are over sooner.
The special sauce
It accounts for your card draw, your ramp, and the other things that change your land drops and casting, which I don't think other tools like this do. It sorts your spells by reading their oracle text, and you can recategorize any it gets wrong.
Credits
Of course, huge credit to Frank Karsten, whose analysis the land count comes from:
Card data provided by Scryfall.