Sourcegraph for GitHub - Browse and search GitHub like an IDE
Gitpod - One click dev environment for GitHub
JSONView - Validate and view JSON documents.
JSON Viewer - The most beautiful and customizable JSON/JSONP highlighter that your eyes have ever seen.
JSONLint - JSON Lint is a web based validator and reformatter for JSON, a lightweight data-interchange format.
Sourcegraph - Sourcegraph is a free, self-hosted code search and intelligence server that helps developers find, review, understand, and debug code. Use it with any Git code host for teams from 1 to 10,000+.