JSON Viewer is a free online tool that transforms JSON, YAML, XML, CSV, TOML, TOON, and Mermaid data into interactive visual graphs for developers and data analysts.
What is JSON Viewer?
JSON Viewer is a web-based application that converts structured data files (JSON, YAML, XML, CSV, TOML, TOON) and Mermaid diagram code into interactive visual graphs. It accepts raw input via paste, file upload, or URL and outputs navigable diagrams, tree views, tables, and charts. The tool runs in any modern browser and is also available as a Chrome extension and a VS Code extension. It is developed and maintained by jsonviewer.tools.
Key Features
- Multi-format input — Accepts JSON, YAML, XML, CSV, TOML, TOON, and Mermaid as input and converts them into interactive visual diagrams in seconds.
- Interactive graph visualization — Displays data as a zoomable, pannable graph with automatic layout; supports custom node colors and personalized themes (Pro).
- Compare JSON graphically — Side-by-side visual diff viewer for multiple JSON files, highlighting differences between versions at a glance.
- Edit JSON from diagrams — Modify node values directly in the graph view without switching to raw JSON text.
- AI-powered generation — AI assistant can generate JSON from images or create dummy JSON based on user prompts.
- Chrome & VS Code extensions — Free extensions let you visualize JSON instantly on any webpage or within the VS Code editor without copying and pasting.
- Mermaid diagram editor — Create flowcharts, sequence diagrams, and ER diagrams using Mermaid syntax with real-time preview and syntax highlighting.
- Export and sharing — Download diagrams as images (free, no watermark on Pro), save documents to secure cloud storage, and share via link (Pro).
Who is it for?
- Developers — to explore and debug JSON API responses, compare configurations, and test REST endpoints with integrated diagram tools.
- Data analysts — to visualize complex nested JSON files as graphs for better understanding of data structure and relationships.
- Web developers — to quickly format, validate, and visualize JSON from any website using the Chrome extension.
- Students and educators — to learn JSON, XML, and YAML structure through interactive visual representation and compare data formats.
What can you do with JSON Viewer?
- Visualizing API responses — Paste JSON from REST APIs to see an interactive graph instead of raw text, making it easier to navigate nested objects.
- Comparing JSON files — Use the side-by-side diff to spot changes between configuration files or API payloads during debugging.
- Creating diagrams from code — Use the Mermaid editor to turn code into flowcharts for documentation or presentations.
- Generating test data — Use the AI assistant to create dummy JSON based on a prompt or even from an image.
Pricing
JSON Viewer offers a free plan with unlimited downloads, Chrome/VS Code extensions, and basic visualization features. The Pro plan costs $2.49 per month (or yearly billing) and adds an ad-free experience, diagram editing, unlimited diagrams, custom themes, watermark-free downloads, save and share documents, API access, large file support, an AI assistant, and an Android app.
FAQ
Is JSON Viewer free?
Yes, the free plan includes unlimited downloads, powerful Chrome and VS Code extensions, and basic visualization tools. The Pro plan removes ads and adds advanced features like custom themes and AI assistance.
What formats can I import?
JSON Viewer supports JSON, YAML, XML, CSV, TOML, TOON, and Mermaid syntax. You can paste text, upload files, or load from a URL.
Is my data secure?
Your data remains private. It is stored only if you manually upload it to the cloud (Pro feature). For typical use, data is processed in your browser and not sent to servers.
Can I use JSON Viewer offline?
No, JSON Viewer is primarily a web-based tool and requires an internet connection. The Chrome and VS Code extensions also need connectivity to function.
Is there an Android app?
Yes, the Android app is available on Google Play Store. It is free to use, and Pro subscribers can log in to access premium features without an additional purchase.
