YNAB is as much a method as an app. Users assign each dollar of income to a category, such as rent, groceries, or savings, and update the plan as real spending happens. When money moves between categories, the app shows the tradeoff. The idea is to work from money you already have, not money you expect, which many people find reduces financial stress.
Features support that approach. Bank syncing imports transactions, goals track bills and savings targets, reports show spending trends, and shared budgets let partners manage money together. The company offers workshops and guides that teach the approach, which is a big part of why users stick with it. There is a mobile app and a web version.
YNAB is paid with a trial, and it asks for more effort than apps that categorize spending automatically. It is not an investment or net worth tracker. Alternatives include Monarch Money, Copilot, Actual Budget as open source, Goodbudget, and spreadsheets. YNAB suits people who want to change spending habits with a hands-on budget.