FLEX vs RenderDoc

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.

RenderDoc is a frame-capture graphics debugger for graphics development, released under the MIT license and available free. It supports Vulkan, D3D11, D3D12, OpenGL, and OpenGL ES, with HLSL, GLSL, and SPIR-V listed among supported languages. Its listed platforms are Windows, Linux, and Android; Nintendo Switch support is noted for authorized developers using NintendoSDK. The API support table marks OpenGL 1.0–2.0 compatibility as supported, while D3D9/10 and Metal are unavailable. Linux support is limited to 64-bit x86. Windows users can choose 32-bit or 64-bit builds or a portable ZIP, and the 64-bit build can capture 32-bit programs. Stable and nightly binary releases are available; stable builds are recommended for new users because nightlies may be less stable. Documentation is online for the latest stable version and included as a CHM file in builds, with introductory videos also linked. The project lists GitHub issues, email, IRC, and Discord for questions and problems. RenderDoc is intended for debugging programs users created; its public support channels do not allow discussion of capturing programs they did not create.