compare · developer

best json formatter
extensions 2026.

Q: Does jsonyo send my JSON data to the internet?

No. Every operation in jsonyo runs locally in your browser tab using JavaScript. No external API call is made, no analytics are fired, and no data is uploaded. This makes it safe for private JSON, internal APIs, data behind firewalls, or anything you wouldn't want leaving your machine.

Q: Can a JSON formatter extension also validate JSON?

jsonyo validates JSON with AJV, one of the fastest JSON schema validators available. Paste your JSON and it shows pass/fail with the exact line and column number of any error. Most basic JSON Formatter extensions only pretty-print; they don't tell you why a JSON is invalid.

Q: What is JSONPath and why would I want it in a browser extension?

JSONPath (and JMESPath) let you query nested JSON with expressions like $.users[0].name or items[*].id. Instead of manually expanding a tree, you write a query and get the matching nodes back instantly. jsonyo includes a full JSONPath query engine in the browser popup — useful for quickly extracting values from API responses or large config files without opening a terminal.

Q: Can I diff two JSON files in a browser extension?

jsonyo includes a Diff mode: paste two JSON blocks side-by-side and it highlights added, removed, and changed paths. This is useful when comparing API responses, config versions, or feature flag payloads. No other popular JSON Formatter extension includes a diff view.

format, validate, query, diff and minify JSON — entirely in your browser.

most JSON formatter extensions do one thing: pretty-print. jsonyo does six. it also validates with AJV, queries with JSONPath, diffs two payloads, shows structure stats, and minifies output — and nothing ever leaves your tab.

install on Chrome

install on Firefox

install on Edge

v1.0.0·free forever·manifest v3

comparison

jsonyo vs JSON Formatter vs JSON Viewer

most popular JSON extensions focus on the prettify use case only. here is an honest feature breakdown across the most-installed alternatives.

feature	jsonyo	JSON Formatter (callumlocke)	JSON Viewer (tulios)
Format / pretty-print	✓	✓	✓
Syntax validation with error location	✓ AJV, line + column	partial basic check	partial basic check
JSONPath / JMESPath queries	✓ full query engine	✗	✗
JSON diff (side-by-side)	✓ added / removed / changed	✗	✗
Structure stats (depth, counts)	✓ objects, arrays, depth	✗	✗
Minify / compact output	✓	✗	✗
Zero data leaves your browser	✓ 100% local	✓	✓
Works on private / firewalled JSON	✓	✓	✓
Chrome	✓	✓	✓
Firefox	✓	✗	✓
Edge	✓	✗	✗
Manifest V3	✓	partial	partial
Modes / tools in one popup	6	1	1
Free	✓	✓	✓

Accuracy as of May 2026. Store listings and feature sets change; verify the current feature sets on each extension's store page.

six tools, one popup

what jsonyo does

open the popup, paste JSON (or click "inspect this page" to grab the DOM's JSON), and switch between six modes without leaving the extension.

mode 1

Format

indent raw JSON with configurable spacing. syntax highlighting for keys, strings, numbers, booleans and nulls.

mode 2

Validate

AJV-powered schema validation. instant pass/fail with the exact line and column of any syntax error.

mode 3

Query

JSONPath/JMESPath expressions like $.users[0].name or items[*].id over the parsed tree.

mode 4

Diff

paste two JSON blocks side-by-side. see added, removed and changed paths highlighted inline.

mode 5

Stats

count of objects, arrays, strings, numbers, booleans, nulls plus maximum nesting depth.

mode 6

Minify

strip whitespace, produce a single-line compact JSON string ready to paste into code or a POST body.

privacy

zero data leaves your tab

every operation in jsonyo runs in your browser tab using JavaScript. no external API call is made at any point. this means:

private API responses stay private
internal JSON behind a corporate firewall can be inspected safely
staging or localhost JSON is fine to paste
no account, no sign-in, no analytics ping on first install

get jsonyo for Chrome

get jsonyo for Firefox

get jsonyo for Edge

faq

frequently asked questions

What is the best JSON formatter Chrome extension in 2026?

jsonyo is a strong choice for developers who need more than just formatting. it includes six tools in one popup — Format, Validate, Query, Diff, Stats, Minify — all running entirely in your browser with no server calls.

Does jsonyo send my JSON data to the internet?

No. every operation runs locally in JavaScript. no external API call, no analytics, no upload at any point. safe for private JSON, internal APIs, and anything behind a firewall.

Can a JSON formatter extension also validate JSON?

jsonyo validates with AJV, one of the fastest JSON schema validators. paste JSON and it shows pass/fail with the exact line and column of any error. most basic formatter extensions only pretty-print.

What is JSONPath and why would I want it in a browser extension?

JSONPath lets you query nested JSON with expressions like $.users[0].name or items[*].id. instead of manually expanding a tree, you write a query and get the matching nodes instantly — useful for exploring API responses or large config files.

Can I diff two JSON files in a browser extension?

jsonyo's Diff mode lets you paste two JSON blocks and highlights added, removed, and changed paths. no other popular JSON Formatter extension includes a diff view in the popup.

Does jsonyo work on Firefox and Edge as well as Chrome?

Yes. jsonyo is available on Chrome Web Store, Firefox Add-ons, and Microsoft Edge Add-ons. all three versions are identical in functionality and built from the same Manifest V3 codebase.

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