Build forms from JSON Schema, easily template-able
...If values are valid, the JSON Form library uses submitted values to create the JavaScript data structure that matches the data model. The layout of the generated HTML form may be entirely fine-tuned through a simple declarative mechanism. If you're more of the acting type than of the reading type, the JSON Form Playground is a simple JSON Form editor that lets you try out and extend all the examples in the doc.
GUI app for editing, visualizing, and manipulating JSON data
JSON-Splora is a GUI for editing, visualizing, and manipulating JSON data with jq or JavaScript. The editor is a JavaScript editor, and the input is parsed as json5. This allows for comments as well as a relaxed JSON input format. Once the editor has valid JSON, an input window will appear below, allowing you to manipulate the object with JavaScript or jq.
MixDEM a web based ETL tools meant for Web integration, Data transformation and Mashup edition. It include MixDEM ETL Engine created using ZEND Framework, and MixDEM GUI Editor an AJAX IDE that enable developers to quickly and easily create applications.