https://app.codecrafters.io/catalog https://app.codecrafters.io/courses/bittorrent/overview https://app.codecrafters.io/courses/claude-code/overview https://app.codecrafters.io/courses/dns-server/overview https://app.codecrafters.io/courses/git/overview https://app.codecrafters.io/courses/grep/overview https://app.codecrafters.io/courses/http-server/overview https://app.codecrafters.io/courses/interpreter/overview https://app.codecrafters.io/courses/kafka/overview https://app.codecrafters.io/courses/redis/overview https://app.codecrafters.io/courses/shell/overview https://app.codecrafters.io/courses/sqlite/overview https://app.codecrafters.io/tracks/c https://app.codecrafters.io/tracks/clojure https://app.codecrafters.io/tracks/cpp https://app.codecrafters.io/tracks/crystal https://app.codecrafters.io/tracks/csharp https://app.codecrafters.io/tracks/dart https://app.codecrafters.io/tracks/elixir https://app.codecrafters.io/tracks/gleam https://app.codecrafters.io/tracks/go https://app.codecrafters.io/tracks/haskell https://app.codecrafters.io/tracks/java https://app.codecrafters.io/tracks/javascript https://app.codecrafters.io/tracks/kotlin https://app.codecrafters.io/tracks/ocaml https://app.codecrafters.io/tracks/odin https://app.codecrafters.io/tracks/php https://app.codecrafters.io/tracks/python https://app.codecrafters.io/tracks/ruby https://app.codecrafters.io/tracks/rust https://app.codecrafters.io/tracks/scala https://app.codecrafters.io/tracks/typescript https://app.codecrafters.io/tracks/zig