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JSON Editor: Smart Json

One JSON document, three views that all edit.

  • Editor, tree & graph
  • Live JSONPath
  • Structural diff
  • Offline, no account
App Store
Why it exists

Most JSON apps on a phone are viewers wearing an editor's name: they pretty-print, they collapse, and that is the end of it. Smart Json starts from the view nobody else offers, a node-link graph you can tap to change a key, a type or a value, and then keeps it honest by making the text the single source of truth. Edit in any of the three views and the other two follow, because a view that can drift from the document is worse than no view at all.

Five phone screens: an API response drawn as a node-link graph, the same document as an outline tree, an inline node editor open over the graph, a JSONPath filter expression matching two nodes, and a key being renamed in the outline.

Three linked views, one source of truth

The same document is a syntax-highlighted editor, a collapsible tree and an interactive graph. All three edit. The text is authoritative, so tree and graph edits are re-serialized rather than tracked separately, and nothing drifts out of sync.

Editor

  • Syntax highlighting that re-tokenizes only what you typed, so it stays fast.
  • Line-number gutter, wrap and font size controls.
  • A punctuation bar above the keyboard: braces, brackets, quotes, true, false, null, indent, undo and redo.
  • Invalid JSON gets a plain-language banner naming the problem, its line and its column.
  • Tap Go to jump the caret there, or Fix to repair comments, trailing commas, single quotes and unquoted keys.

Tree

  • A collapsible outline with indent guides, type badges and child counts.
  • Search across keys and values, filter by type.
  • Edit any node in place: rename, change type, reorder, duplicate, add, delete.

Graph

  • A tidy node-link diagram, left to right or top to bottom.
  • Pinch to zoom, pan, tap a node to expand it, fit to screen.
  • Tap a node to open an editor docked right underneath it: the graph edits as well as it browses.
  • Expand all, expand to a depth, or expand one subtree.
  • Export the graph as PNG or SVG.

Find what you need

  • One find bar in every view, with match case and wrap-around in the editor.
  • Structural search in the tree and graph, with scope and type filters, stepping through hits.
  • JSONPath that evaluates live and tints its matches in the editor, the tree and the graph at once.
  • A documented subset of RFC 9535, filter expressions included.

Compare and convert

  • Diff the open document against a file, the clipboard or a URL.
  • Structural, not textual: reformatting is not a change.
  • Changed subtrees are tinted in the graph, and array elements are paired by identity when they have one.
  • Preview your document as YAML, CSV, TOML or XML, each with a plain statement of what that format cannot carry.

Getting JSON in and out

  • Open files from iCloud Drive and Files, with proper open, save and rename.
  • Start a document from the clipboard or from a URL, sending your own headers on the request.
  • A share extension accepts JSON from any app, and JSON5 files open too.
  • Beautify, minify, sort keys, auto-fix, escape and unescape a JSON string literal.
  • Undo and redo everything, with one history per document shared by every view.

Built right

Native SwiftUI for iPhone and iPad, with full keyboard support, light or dark. A hand-written parser preserves key order and keeps number literals exactly as written, so nothing is lost on a round trip. It works entirely offline: no account, no sign-in, no analytics, and no data leaves your device.

Questions

Can I edit in the graph, or only look at it?
You can edit. Tap a node and an editor docks right underneath it, where you can change the key, the type or the value, add a child or delete the node. Graph edits are re-serialized into the text, so the editor and tree stay in step.
Do the three views ever get out of sync?
No. The text is the single source of truth, and tree and graph edits are re-serialized back into it, so the other two views always reflect the same document.
Does it support JSONPath?
Yes. Type an expression and it evaluates live, tinting its matches in the editor, the tree and the graph at the same time. It implements a documented subset of RFC 9535, filter expressions included.
What does the diff compare?
Structure, not text. You can diff the open document against a file, the clipboard or a URL, and reformatting alone never registers as a change. Changed subtrees are tinted in the graph, and array elements are paired by identity when they have one.
Which formats can it convert to?
YAML, CSV, TOML and XML, each preview stating plainly what that format cannot carry. The graph also exports as PNG or SVG.
What is free and what needs Pro?
Every feature computes and shows you its result for free. Pro is for keeping that result: extracting JSONPath matches to a new document, query history and saved queries, text diff with patch export, and saving or sharing a conversion.

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