Raw API responses become a clean, collapsible, colour-coded tree — automatically. A virtualized renderer keeps huge files smooth, a built-in jq filter slices them down, and everything runs on your machine. No copy-pasting into another tab.
Free forever · Open source · No account · Zero network calls
Most viewers try to draw every node at once and lock up the moment a response gets large. JSON Peek only renders what's on screen, so a multi-megabyte document with hundreds of thousands of nodes stays smooth to scroll, expand and search.
Only the rows inside the viewport are ever mounted. Scrolling, expand-all and collapse-all stay responsive whether the document is 2 KB or 20 MB — no spinner, no locked tab, no crash.
Non-JSON pages cost effectively nothing: a quick content-type and first-character check runs and exits in under a millisecond, so JSON Peek never slows down your normal browsing.
Viewport-only DOM<1 ms on other pagesDeep-doc safeA jq-style filter bar is built right in — paths, iteration, pipes, select(), map(), keys, length and more. It's a dependency-free subset that runs locally, so slicing a huge response down to the part you care about takes a couple of keystrokes.
Real-world JSON is rarely pristine. JSON Peek recovers what it can, tells you what it fixed, and points at the exact spot when something's genuinely broken — instead of showing a blank page.
Objects and arrays fold and unfold with indent guides, key and item counts on collapsed nodes, and syntax colours for every data type. Expand-all and collapse-all in one click.
Search across the whole document at once. Matches auto-expand into view with next / previous jumping and a live count, so a value buried deep in a big response is one keystroke away.
Paths, iteration, pipes, select(), map(), keys, length and more — a dependency-free jq subset that runs entirely on your machine.
Line-delimited log and streaming formats are detected automatically and shown as a clean array — a case most viewers miss entirely.
Copy the whole document pretty or minified, any value, or the exact path to a node. Export to JSON, minified JSON, or flattened CSV.
Paste any JSON or JSONL to format, validate and explore it — no need to open a URL first. Right-click selected text to send it straight in.
Hit any endpoint that returns JSON and it's a tree instantly — no button, no paste. The raw response is one keystroke away with R.
/ to search, R to toggle raw, E to expand all, C to collapse. The jq bar filters as you type.
Open the scratchpad from the popup or a right-click, paste JSON or JSONL from anywhere, and get formatting, validation and a clear error location.
Every feature is free permanently — no account, no subscription, no locked tier. JSON Peek makes zero network calls and has no analytics or tracking: the JSON you view, your preferences and your ignored-site list never leave your device, because there's nowhere for them to go. The code is open and auditable. It's funded by goodwill — if it earns a place in your toolbar, you can leave a tip.
JSON Peek is one of a family of independent Chrome extensions built in the UK. No bloat, no dark patterns.
A precision color picker with a magnifying loupe eyedropper, a real color wheel, palettes, contrast checking and code-ready export.
Cleans tracking junk off a link the moment you copy it — short, private URLs, without breaking the pages you browse.
An all-in-one document suite for the browser — convert, merge, split and edit files without uploading them to a stranger's server.
See the full lineup at niallcodes.com →
Yes — that's the point of it. JSON Peek uses virtualized rendering, so only the rows currently on screen are drawn. A multi-megabyte response with hundreds of thousands of nodes stays smooth to scroll, expand and search where other viewers freeze or crash the tab.
The filter bar accepts a subset of jq — paths like .items[], pipes, select(), map(), keys, length and more — to narrow a big document down to what you want. You don't have to use it; the tree, search and export all work without ever touching it. It's there when you need it.
It recovers common problems — trailing commas, comments and single-quoted strings — and shows a note about what was fixed. Line-delimited JSONL/NDJSON is detected automatically, and HTML error pages served as JSON are flagged rather than mangled. When JSON is genuinely invalid, it points at the exact line and column instead of showing a blank page.
Copy the whole document pretty-printed or minified, any single value, or the exact path to a node. Export the document — or a jq-filtered slice of it — as JSON, minified JSON, or flattened CSV. There's also a window.json hook so you can poke at the parsed value in DevTools.
Yes — every feature, free permanently, with no paid tier and nothing that moves behind a paywall later. There's no account and no license. If JSON Peek helps you, you can leave an optional tip at ko-fi.com/niallcodes. That's the whole model.
No. No account, no analytics, no tracking, and no network calls at all — JSON Peek never contacts a server. It reads the current page's text locally only to detect and render JSON, and that content is never transmitted or stored off-device. Your preferences and ignored-site list live in the browser's own storage. Full detail is in the privacy policy.