JSLint is a debugging tool that scans JavaScript source code for syntax, performance, and security issues. It displays messages describing any problems it finds and their approximate location in the source. Features include: open and check for syntax/performance/security issues in JavaScript files; paste/type JavaScript source code and check for potential issues instantly; one-click or ⌘L keyboard shortcut for checking; intuitive lint results including location and issue description; and double click on a result item to jump to the specific location.
Blinged JSON Validator is a free app to validate JSON files with syntax highlighting, whitespace indentation, error messaging, and hotkeys.
