Free Online JSON Tools
Everything you need to work with JSON — in one place
JSON has become the default data-interchange format across web APIs, config files, and NoSQL databases. Working with it every day still means a lot of small, repetitive tasks: pretty-printing a response, validating a payload, converting a sample into typed code, or comparing two documents to spot what changed. This category collects fast, privacy-first JSON utilities that cover those tasks end to end. Every tool runs entirely in your browser using pure JavaScript — nothing is uploaded, logged, or stored — and every tool page ships with docs, code samples, and edge-case notes so you understand exactly what happens to your data.
All JSON Tools
JSON Formatter
Format, beautify, and validate JSON online. Free, fast, and 100% local — your data never leaves your browser.
JSON Validator
Validate JSON online with instant error location and structure statistics (depth, keys, node types). 100% local — your JSON never leaves the browser.
JSON Schema Validator
Validate a JSON payload against a JSON Schema online. Supports Draft 2020-12, format validation (date-time, uuid, email, uri), and shows errors by JSON pointer path. 100% local — nothing is uploaded.
JSON Schema Generator
Generate a JSON Schema from a sample JSON — output as standard Draft 2020-12, OpenAI function calling schema, or Anthropic tool_use schema. Powers LLM structured output pipelines.
JSONPath Tester
Test JSONPath expressions against sample JSON online. Get instant, highlighted results for queries like $.store.book[*].author.
JSON Diff
Compare two JSON documents structurally and see added, removed, and changed values by path. Handles nested objects, arrays, and type changes.
JSON Escape
Escape strings for use inside JSON, or unescape JSON string literals back to plain text. Handles quotes, newlines, tabs, and Unicode.
JSON Repair
Automatically fix invalid JSON — trailing commas, single quotes, unquoted keys, comments, markdown code fences, and Python-style True/False/None. Purpose-built for LLM output. 100% local.
JSON Sort
Alphabetically sort JSON object keys online. Optional deep sort, ascending / descending, and Minified / 2-space / Tab output. Useful for canonical form, cleaner diffs, and deterministic hashes. 100% local.
JSON Flatten
Flatten nested JSON to a single-level 'path → value' map (dot / bracket notation), or unflatten a flat map back into nested JSON. Compatible with lodash and Spring conventions. 100% local.
JSON Path Finder
Search JSON for keys or values and get back JSONPath expressions for every match. Reverse of a JSONPath tester — perfect when you know what you're looking for but not where it lives. 100% local.
JSON Minifier
Minify JSON online — strip all whitespace, see exact bytes saved, get a valid RFC 8259-compliant output. Free, no signup, runs entirely in your browser.
JSON to Table
Paste a JSON array and get a sortable HTML table. Click column headers to sort, handles nested objects and arrays as strings. Perfect for inspecting API responses or spreadsheets. 100% local.
JSON Merge
Deep merge two JSON objects — base + override. Nested objects are recursively merged. Perfect for config files and API responses. 100% local.
JSON to Form
Paste JSON to render it as an HTML form. Auto-detects field types from values — text, number, checkbox. 100% local.
When to use these tools
Reach for these tools when you need to inspect an API response, debug a config file, generate types from a sample payload, migrate data between formats (JSON, YAML, CSV), or compare two versions of a JSON document structurally rather than as raw text.
Frequently Asked Questions
Is my JSON uploaded to any server?
No. Every tool in this category runs entirely in your browser as client-side JavaScript. Your data never leaves your device.
Which JSON specification do these tools follow?
The tools follow RFC 8259 (the current JSON standard). Non-standard extensions like JSONC (JSON with comments) or JSON5 are called out explicitly where relevant.
What is the difference between a JSON formatter and a JSON validator?
A formatter reflows the text with consistent indentation for readability. A validator checks whether the input actually parses as valid JSON. Our JSON Formatter does both in one step.