View, search, compare and convert JSON, YAML, XML, CSV and TOML, in the tab or a scratchpad. Click the icon or press Alt+Shift+J.
Users
2
store count
Rating
0.0 / 5
unchanged in 30 days
Ratings
0
total ratings
Store rank
#356K
#271K among extensions
Version
1.1.0
updated 7 Oct 2026
About Data Viewer by Code Red
Data Viewer turns raw data you open in a tab into a viewer you can actually read, search and copy from.
Open an API response or a data file, on the web or from your disk, then click the Data Viewer icon or press Alt+Shift+J (or right-click → View as data): it shows as a collapsible tree, a sortable table or numbered text, in place. Prefer it to happen by itself? Turn on automatic formatting in the popup.
• Tree with counts, colours, collapse all, expand all and expand to any depth. Keyboard friendly.
• Table for CSV, TSV and JSON arrays of objects: sticky header, sort by any column, filter as you type.
• Search keys and values, or a /regular expression/, with highlights, next and previous, and "only matches".
• Click any value to copy it. Copy the JSONPath (or XPath, for XML) of any node.
• Exact: 64-bit ids are shown as sent, never rounded; keys stay in the order the server sent them.
• Big files: 50 MB documents open without freezing the tab.
• Broken documents show what is wrong and on which line.
• Pretty or raw text with line numbers, copy all, save as a file.
• Explore it visually: a treemap or sunburst of where the size is, a node map you pan and zoom, automatic charts of numbers, dates and categories, and an inferred schema with types, optional fields and examples. Pick anything in a chart and jump to it in the tree.
• Nine themes, from Synthwave to paper-light and two high-contrast ones, previewed live as you point at them.
• Keyboard shortcuts: / to search, [ and ] to collapse and expand, ? for the rest, Alt+Shift+J to switch a tab between the viewer and the raw page.
• Optional automatic formatting: data documents open in the viewer as they load. Off for any site in one click, and per format.
Installs with no access to your sites. It runs in a tab only when you ask (icon, shortcut or menu), or everywhere only if you turn on automatic formatting and allow it. Even then it only acts on documents the browser shows as plain text or as an XML tree; normal web pages are left alone.
Free and open, with no ads, no tracking and no account needed. Everything happens in your browser; nothing is sent anywhere. Signing in with your Code Red account is optional. Tips keep it free.