koans.app

Learn a programming language by fixing failing tests, right in your browser: Clojure, Go, JavaScript, Lua, OCaml, PHP, Prolog, Python, R, Raku, Ruby, Scheme, SQL and TypeScript. Nothing to install, no account.

• Clojure Koans: Learn Clojure from its data structures to its macros (79 koans)
• Go Koans: Learn Go from its zero values to its goroutines (73 koans)
• JavaScript Koans: Learn modern JavaScript from its values to async functions (89 koans)
• Lua Koans: Learn Lua from its tables to its metatables (73 koans)
• OCaml Koans: Learn OCaml from its types to its modules (75 koans)
• PHP Koans: Learn modern PHP from its arrays to its enums (79 koans)
• Prolog Koans: Learn Prolog from its facts to its grammars (70 koans)
• Python Koans: Learn Python from the first assertion to its built-in collections (86 koans)
• R Koans: Learn R from its vectors to its data frames (78 koans)
• Raku Koans: Learn Raku from syntax to culture (105 koans)
• Ruby Koans: Learn Ruby from its objects to its blocks (90 koans)
• Scheme Koans: Learn Scheme from its lists to its continuations (74 koans)
• SQL Koans: Learn SQL from SELECT to window functions (72 koans)
• TypeScript Koans: Learn TypeScript’s types, from annotations to generics (65 koans)