FLEX vs Ruby debug

FLEX is a free, open-source debugging and exploration library for iOS applications. It runs inside the app and places a toolbar in a window above it, allowing developers to inspect and change application state without an LLDB or Xcode connection or a remote debugging server. The tool can inspect view hierarchies, find live heap objects, show and modify properties and ivars, and call methods. Its network history covers NSURLConnection and NSURLSession requests with timing, headers, and responses. Developers can browse app bundles and sandboxes, inspect SQLite and Realm databases, and view or edit NSUserDefaults values, including strings, numbers, arrays, and dictionaries. FLEX works in the iOS Simulator and on physical devices, supports Objective-C and Swift, and requires an iOS 9-or-later target. Installation options include CocoaPods, Carthage, Buck, manual Xcode integration, and Swift Package Manager.

Ruby debug is a free, BSD-2-Clause open-source debugger for Ruby MRI 2.7 and later, delivered for Linux and self-hosted use. Its console evaluates Ruby expressions, inspects program state, controls execution, sets conditional and exception breakpoints, and enables tracing. The debugger can record execution and replay it by stepping backward through the log. Remote sessions work over UNIX domain sockets or TCP/IP, allowing a console to attach to a running program. An IRB console adds autocompletion, multiline input, and commands including `show_source` and `show_doc`. The `rdbg` command launches Ruby scripts and commands such as Rails, Rake, and RSpec under debugging. Frontends are described for VS Code and Chrome DevTools; VS Code requires the vscode-rdbg extension. Installation uses `gem install debug` or a Gemfile entry. The project reports no performance penalty when not stepping and with no breakpoints set. It warns that remote messages are unencrypted and that `debug/open_nonstop` can expose access without stopping the program.