OneFreePlaceDeveloper Tool #332
Developer Tools · JSON

JSON Tree Viewer

Turn dense JSON into a fast, navigable tree. Search keys, values or paths, inspect exact JSONPath and JSON Pointer locations, focus on any subtree, and explore large arrays without rendering thousands of rows at once.

100% local · nothing uploaded

1 · JSON source

Drop a .json, .jsonl or .ndjson file here · UTF-8 and UTF-16 BOM supported
Tip: Ctrl/⌘ + Enter parses. The viewer only creates DOM rows for branches you open, and large arrays are paged in 200-item chunks.

2 · Explore the tree

Nodes—
Objects—
Arrays—
Max depth—
Source size—
Format—
0 / 0
Select a node to inspect its exact location and value.

Why this viewer is different

Many JSON viewers become sluggish because they create a DOM row for every field. OneFreePlace renders branches only when you expand them and pages large arrays in 200-item chunks. You can inspect deeply nested data without turning a 100,000-item array into 100,000 HTML elements.

Search understands keys, primitive values and full paths. Regular-expression and case-sensitive modes make it practical for API debugging and log inspection.

Precise developer paths

Every selection exposes both JSONPath-style notation and standards-based JSON Pointer. Keys that are not safe JavaScript identifiers are automatically quoted in JSONPath, while ~ and / are escaped correctly in JSON Pointer.

Use Focus selected when one branch is all you need. Breadcrumbs always let you climb back through the hierarchy.

Privacy and file handling

Parsing, searching, path generation and downloads happen in your browser. The tool contains no analytics SDK and no upload endpoint. Local files are read with the browser File API and are not persisted by the tool.

UTF-8, UTF-8 BOM, UTF-16LE BOM and UTF-16BE BOM are supported. JSON Lines / NDJSON can be opened directly and is displayed as a record array.

Keyboard workflow

  • Ctrl/⌘ + Enter — parse the input.
  • Ctrl/⌘ + F — focus tree search while in Viewer.
  • ↑ / ↓ — move through visible tree rows.
  • ← / → — collapse/expand or move to parent/child.
  • Enter — toggle the selected container.
  • Ctrl/⌘ + C in the tree — copy selected JSONPath.

Practical use cases

  • Explore unfamiliar API responses before writing integration code.
  • Audit configuration files and locate deeply nested flags.
  • Inspect exported datasets without uploading confidential content.
  • Navigate JSON Lines logs as individual records.
  • Copy stable JSON Pointer locations for patches, tests or documentation.

Limits and accuracy

The browser still needs memory to parse the full JSON structure. Lazy rendering protects the page from excessive DOM work, but it cannot remove the browser's memory limits. For multi-gigabyte files, a native streaming viewer is more appropriate.

Strict JSON follows the browser's standards-compliant parser. Duplicate object keys are audited before parsing because JavaScript objects retain only the last value for a repeated key.

OneFreePlace tools are designed for immediate use: no account, no subscription, no forced upload, and no feature gate for the core viewer.