Open source. Open possibilities.

A highly customizable calendar library for Android and Compose Multiplatform, providing the logic for date displays while allowing developers to define the UI.

Arrow is a Python library that simplifies creation, manipulation, formatting, and conversion of dates, times, and timestamps with timezone awareness and human-friendly API.

Day.js is a minimalist 2kB JavaScript date-time library offering a Moment.js-compatible API. It is immutable, chainable, supports i18n and plugins, and works across modern browsers.

date-fns is a modular JavaScript date utility library with 200+ pure functions for parsing, formatting, comparing and manipulating dates in browsers and Node.js. It uses native Date objects, is written in TypeScript, supports tree-shaking and dozens of locales, and adds first-class time zone support in v4.0.