An advanced JSON editor that runs in your browser
Edit JSON with a real code editor, inspect the same document as a tree, grid or graph, and analyse it without sending a byte to a server.
What makes it advanced
The editor is the entry point to a complete workbench rather than a single textarea. The same parsed document powers code, tree, grid, graph, profiling, query and transformation views, so your selection and structure stay in sync.
- Monaco with folding, bracket matching, multi-cursor and search/replace
- Precise syntax errors with line and column, plus duplicate-key warnings
- Large integers and decimals preserved rather than rounded through JavaScript numbers
- JSONC and JSON5 are accepted and clearly labelled as extensions
- Command palette, customisable shortcuts and light/dark/system themes
Local by design
Documents are opened with the File System APIs available in the browser and stored in IndexedDB only if you keep them in the workspace. There is no account and no upload endpoint.
Questions
Does it support huge files?
Parsing runs in a Web Worker and the tree/grid are virtualized. Small files are immediate and 10 MB files are comfortable. 100 MB files are viewable with progressive exploration, but editing very large documents is limited by browser memory; the app reports sizes and parse times instead of promising unlimited support.
Are numbers rounded?
No. The parser stores large numbers in a lossless representation and serialises the original text, so identifiers and monetary values are not silently changed.
Go further in the studio
This page is intentionally a single-purpose tool. The full studio adds synchronized views, profiling, data-quality rules, schema comparison, three-way merge, transformation pipelines, timelines and local persistence. Open it with the same document and continue where this page stops.