Firefox add-on

Jaywalk

Open any JSON URL in Firefox and get a clean, collapsible tree instead of a wall of text. Large numbers stay exactly as the server sent them, so an ID like 12345678901234567890 is not rounded the way JavaScript rounds it. It gets a small "exact" tag so you can see that at a glance.

Parsed tree of an order with a large id kept exact, with filter and search in the toolbar.

Measured

A 4 MB JSON file opened in about half a second in our tests (19 Oct 2026, Jaywalk 1.1.0).
Large integer IDs are shown digit for digit and tagged "exact".

Find things fast

Filter by path, for example $.items[*].name, $..id, [0:10] or [-1].
Search keys and values, then press Enter to jump from hit to hit.
Copy the path or the value of any line, or show only that branch.

The path filter $.order.lines[*].price returns the two line prices.

Searching for "mouse" highlights the matching line.

Compare two documents

Put two JSON documents side by side. Array items are matched by id when they have one, so a reordered list does not show up as one big change.

Two JSON documents compared, array items matched by id, four differences listed.

See the shape of it

Chart view draws the document as boxes and lines. Click a box to open it, drag to move it, and save the chart as SVG.
Breadcrumbs above a focused value take you back up one step at a time.

The same order as a chart, with the first line and tracking opened.

Other formats

Paste or open YAML and XML and get JSON back. XML attributes become @name.
Turn JSON into YAML, or a list of objects into CSV. Cells that look like spreadsheet formulas are made safe.
Reads NDJSON and JSONP too.

Everyday tools

Raw and Parsed toggle, sort keys, copy, copy minified, save as .json.
Broken JSON shows the line and column, with the bad character marked.
Ctrl+click a toggle to open or close all its siblings.
Type json in the DevTools console to work with the data.
Light, dark or follow the system.
Turn it off for sites you choose, add content types your servers mislabel, and add your own CSS.

Privacy

Jaywalk sends nothing anywhere: no analytics, no ads, no affiliate code and no pop-ups. It only stores your settings (theme, skipped sites, extra content types and your CSS).

Install

Firefox Add-ons (Firefox 142 or later)

Price

Free.