Large JSON Viewer
Inspect large JSON files locally, view useful structure statistics and keep sensitive data on your device.
100% local · files never leave your browser
Private browser tools for developers
Open, search and transform JSON—privately.
Work with JSON and JSONL files directly in your browser. No accounts, no uploads, no waiting.
{ }Built for real data.JSON, JSONL and NDJSON supported
1. Open a file
Drag & drop JSON or JSONL here
orSupports .json, .jsonl and .ndjsonor
{ }
Open a file or try the sample to explore its structure.
The everyday JSON toolkit
One private workbench. Every common JSON task.
Each utility runs locally in your browser, so sensitive API responses, logs and configuration files stay on your device.
Open tool →
JSONL Viewer
Parse newline-delimited JSON into readable records with precise line-level error reporting.
Formatter
Beautify compact JSON for readability or minify it for smaller payloads.
Validator
Validate JSON syntax and get a clear error message when parsing fails.
Tree Editor
Format and inspect JSON before opening it in the visual tree on the main workbench.
JSON Diff
Compare two JSON documents by path and find added, removed and changed values.
JSONPath Tester
Query deeply nested JSON with JSONPath and inspect every matching value.
Schema Generator
Infer a practical JSON Schema from a representative example document.
Schema Validator
Validate JSON data against a JSON Schema using the widely adopted AJV validator.
JSON Repair
Repair common problems such as missing quotes, trailing commas and incomplete structures.
JSON to CSV
Turn arrays of JSON objects into spreadsheet-ready CSV in your browser.
CSV to JSON
Convert CSV rows to structured JSON while preserving quoted commas and headers.
JSON to YAML
Convert JSON to clean, readable YAML for configuration and documentation.
YAML to JSON
Parse YAML safely in the browser and return consistently formatted JSON.
TypeScript Types
Generate readable TypeScript interfaces from representative JSON data.
Go Struct
Generate idiomatic Go structs with JSON tags from sample payloads.
Java Classes
Generate Java records from JSON with nested object and list types.
Flatten JSON
Flatten nested values into dot paths, or rebuild nested JSON from dot-path keys.
Escape JSON
Escape JSON for strings and logs, or decode an already escaped JSON string.
JWT Decoder
Decode JWT headers and payloads locally. Signature verification is intentionally not implied.
♢
Local by design
Your data is none of our business.
JSON Hearth processes files in the browser tab you already have open. Your data is not transmitted to us, stored on a server or used to train anything.
- No account required
- No server uploads
- Works offline after loading