JSON Viewer Formatter Tree

Paste messy JSON and get clean, readable, correctly indented output in one tap. JSONViewer formats, validates, and beautifies any payload — right on your iPhone, fully offline.

Most JSON tools are websites that make you paste sensitive API data into a stranger's server. JSONViewer keeps everything on your device: paste a response, a config file, or a log export, and it pretty-prints with colour syntax highlighting instantly. Invalid JSON is flagged with the exact reason, so you fix broken payloads fast — no guessing, no round trips to a browser.

WHAT YOU GET
- Clean, indented JSON from any pasted or copied payload in one tap
- Instant validation that pinpoints exactly why a payload is broken
- Minify mode to strip whitespace down to a compact one-liner
- An interactive, collapsible tree so you can read deeply nested data at a glance
- JSONPath queries that pull the exact value out of a large response
- A saved library of your own snippets plus ready-to-use sample payloads

PERFECT FOR
- Backend and mobile developers debugging API responses on the go
- QA engineers checking payloads and config files away from a laptop
- Students learning JSON structure with the built-in Learn guide
- Anyone who needs to read or tidy a JSON blob without opening a website

WHY NOT JUST USE A WEB FORMATTER?
Online formatters send your JSON to a remote server — a real problem when the payload holds tokens, user records, or internal data. JSONViewer does all parsing on-device, so your data never leaves your phone and works with no signal at all.

PRIVACY
Your JSON never leaves the device. No accounts, no servers, no tracking — everything runs locally, even in aeroplane mode.

FULL ACCESS
The Format tab — paste, validate, beautify, minify, and copy — is free. Premium unlocks the interactive tree view, JSONPath query, saved snippet library, and expand/collapse controls. Premium is available as a weekly or yearly subscription, or a one-time lifetime purchase:
- Weekly subscription
- Yearly subscription
- Lifetime (one-time purchase, no renewal)
Payment is charged to your Apple ID at confirmation of purchase. Subscriptions auto-renew unless turned off at least 24 hours before the end of the current period. Manage or cancel anytime in App Store settings.

Paste your first payload and tidy it up now.

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Questions? https://web-levi.web.app/#contact