JSON Tree Viewer Online
Open a JSON file to browse it as a tree. Search keys and values, copy the JSONPath of any value, see an array of objects as a sortable table, and open strings that hold JSON as a nested tree. Big numbers stay exact. No account and no upload.
Large JSON Viewer, JSON Browser & JSON Tree for VS Code and Cursor, free
- A worker thread parses the file and only the rows on screen are drawn: a 30 MB array shows its first rows in about 0.6 s.
- Go to line puts the text editor beside the tree at the selected node, and the tree follows the file as it changes.
- Search with next and previous, copy the JSONPath, the JS path or the value, and big numbers kept digit for digit.
Optional Zovo Pro, USD 19 once: export an array to CSV or JSON Lines, and compare two JSON files by path. 3 free tries for each.
Drop a .json file here
or
JSON, JSONC with comments and trailing commas, and JSON Lines, up to 300 MB. GeoJSON, HAR, .ipynb and other JSON files open too.
Open this in VS Code or Cursor
The free Large JSON Viewer extension opens JSON files in VS Code and Cursor as the same fast tree: a worker thread parses the file, Go to line puts the editor beside the tree at the selected node, and the tree reloads when the file changes, with open nodes, the selection and the search kept.
Free, MIT license. About Large JSON Viewer & JSON Tree for VS Code.
Zovo Pro
Export an array to CSV or JSON Lines, and compare two JSON files. Zovo Pro, USD 19 once.
In the Large JSON Viewer extension, Zovo Pro exports an array of objects to CSV or JSON Lines, with nested objects as dotted columns and big numbers kept exact, and compares two JSON files by path, with key order ignored and arrays of objects matched by their id. Each Pro tool works 3 times for free. One payment covers the Pro tools in 22 Zovo extensions. Everything that is free stays free.
After a card payment you get a key on the page. With GitHub Sponsors you sign in from the extension. Details on the Zovo Pro page.
Related tools
- JSONL Viewer & NDJSON Table. Shows large JSON Lines files as a table in VS Code.
- HAR Viewer & HAR File Analyzer. Opens HAR files from browser DevTools with a timing waterfall.
- Excel, CSV and Parquet Viewer. Opens xlsx, csv and parquet files as a sortable table.
- OpenAPI Viewer Online, free in your browser.
- CSV Viewer Online, free in your browser.
- SARIF Viewer Online, free in your browser.
Questions
Is my JSON uploaded anywhere?
No. The page reads the file inside this tab with JavaScript. Its Content Security Policy sets connect-src to none, so the page cannot send your data anywhere. Open the Network tab of your browser tools and you will see no request when a file opens.
How big a file can it open?
Files up to 300 MB. The tree is built only for the parts you open, so a large file shows its first level as soon as it is read. In our test a 74 MB file opened in under a second. Expand all stops at a few thousand nodes so the tab stays quick; use search to reach a value deep in a big file.
Does it keep big numbers exact?
Yes. A 64-bit id such as 18446744073709551615 is shown digit for digit, where JSON.parse would round it, and the page notes how many numbers it kept. This uses the JSON source text access of current Chrome, Edge and Firefox; other browsers say when they cannot.
Can it read JSON with comments?
Yes. JSONC files such as VS Code settings, with // and /* */ comments and trailing commas, open after the comments are skipped, and the page says how many it skipped. JSON Lines files, one value per line, open as an array. For a file that is not valid JSON, the page shows the line and column of the error.
What is the table view?
Click an array of objects, such as the rows of an API response, to see it as a table below the tree: one row per item and one column per key, up to 60 columns. Click a column name to sort it.
What does it do with strings that hold JSON?
A string value that is itself JSON, as in many logs, queues and HAR files, opens as a nested tree under its key, so you can read the payload without copying it out.
Is a hostile file safe to open?
Keys and values are shown as plain text, never as HTML, and nothing from the file runs. Paths are built as text, never as code. Very deep nesting is walked without recursion, so it cannot crash the tab.
Does it work offline?
Yes. After the first visit the page keeps a copy of its own files, so it opens JSON files with no connection.
What is free and what is Zovo Pro?
Everything on this page is free. In the VS Code extension, the tree, search, paths, the table view and Go to line are free too. Export to CSV or JSON Lines and comparing two JSON files are Zovo Pro, with 3 free tries each. One USD 19 payment covers the Pro tools in every Zovo extension.