Question 1

What is a JSON formatter?

Accepted Answer

A JSON formatter (also called a JSON beautifier or JSON pretty printer) takes compact or malformed JSON and reformats it with proper indentation and line breaks, making it human-readable. theJSON provides instant online JSON formatting powered by Monaco Editor with customizable indentation levels.

Question 2

How do I validate JSON online for free?

Accepted Answer

Paste your JSON into theJSON editor and click Validate (or press F6). The tool instantly checks your JSON for syntax errors, highlights invalid lines in the editor, and shows a toast notification with the result. Real-time error squiggles appear as you type.

Question 3

How do I fix or repair invalid JSON automatically?

Accepted Answer

theJSON's Auto-Correct feature uses a 6-strategy repair pipeline to fix invalid JSON automatically. It handles: trailing commas, missing commas, unquoted keys, single-quoted strings, Python literals (True/False/None), hash comments (#), JSON Lines (JSONL) format, JSON embedded inside Markdown code blocks, BOM characters, and truncated JSON. Click Correct and all fixes are highlighted in the editor.

Question 4

How do I compare two JSON files online?

Accepted Answer

Click Compare in theJSON to open the diff tool. Paste the original JSON on the left and the modified JSON on the right, then click Compare. The Monaco-powered diff editor highlights additions (green), deletions (red), and modifications (yellow) side by side. A summary bar shows the total count of added, removed, and changed keys. Toggle between side-by-side and inline diff modes.

Question 5

How do I minify or compress JSON online?

Accepted Answer

Click Compress in theJSON to strip all whitespace and line breaks from your JSON, reducing it to the smallest possible size. This is ideal for reducing bandwidth in API responses, storing JSON in databases, or embedding JSON in source code.

Question 6

What is JSONPath and how do I query JSON with it?

Accepted Answer

JSONPath is a query language for JSON similar to XPath for XML. It lets you extract specific values using expressions. Examples: $.users[*].name extracts all user names; $..price finds all price fields at any depth; $.orders[?(@.total > 100)] filters orders over 100. theJSON has a built-in JSONPath engine — no CDN required — supporting key access, wildcards, array indexing, recursive descent (..), and filter expressions.

Question 7

How do I convert JSON to CSV online?

Accepted Answer

theJSON's Export CSV feature converts a JSON array of objects to a downloadable CSV file. Paste your JSON array into the editor and click Export CSV. Headers are automatically extracted from all unique keys across all objects, and values are properly escaped for CSV. Nested objects are serialised as JSON strings within the CSV cell.

Question 8

How do I sort JSON keys online?

Accepted Answer

Click Sort in theJSON to open the sort options. You can sort JSON object keys alphabetically (A-Z or Z-A), by key length, or by a specific key's value. Enable Deep Sort to recursively sort all nested objects throughout the entire JSON document — not just the top level.

Question 9

Can theJSON handle large JSON files?

Accepted Answer

Yes. theJSON is optimised for large JSON files. Files under 2 MB are formatted synchronously for instant results. Files from 2–5 MB use a background Web Worker so the UI stays responsive. For files over 5 MB, visual graph and tree views are skipped automatically. The Monaco Editor uses built-in large-file optimisations for smooth editing of very large documents.

Question 10

Is theJSON free and is my JSON data private?

Accepted Answer

theJSON is 100% free, ad-free, and requires no registration. There are no advertisements of any kind. It is a completely client-side application — all JSON processing happens in your browser using JavaScript. No JSON data is ever sent to any server, stored in any database, or shared with any third party. Your data never leaves your device.

Question 11

What is JSON flattening and how does it work?

Accepted Answer

JSON flattening converts a nested JSON object into a single-level object where nested keys are joined by a delimiter. For example, {"user": {"name": "Alice"}} becomes {"user.name": "Alice"}. theJSON supports both flatten and unflatten operations with a configurable delimiter (default: dot). This is useful for working with databases, CSV exports, or flat configuration systems.

Question 12

How do I load JSON from a URL?

Accepted Answer

Click Load URL in theJSON, paste any public URL that returns JSON (such as a REST API endpoint), and click Load. The tool fetches the JSON and loads it directly into the editor, ready for formatting, validation, or any other operation. CORS restrictions apply — the URL must return proper CORS headers for cross-origin access.

Question 13

How do I validate JSON against a JSON Schema?

Accepted Answer

Click Schema in theJSON to open the JSON Schema Validator. Paste your JSON Schema (Draft 7) on the left panel — the editor JSON is automatically used as the data to validate. Click Validate to run the check. All validation errors are listed with their JSON path, error message, and the failing keyword (type, required, minimum, pattern, etc.). theJSON uses the Ajv validation library, which is one of the fastest and most spec-compliant JSON Schema validators available.

Question 14

How do I convert JSON to YAML online?

Accepted Answer

Click Convert in theJSON and select 'JSON → YAML' from the format dropdown, then click Convert. The editor JSON is instantly converted to clean YAML format using the js-yaml library. You can also convert YAML back to JSON: select 'YAML → JSON', paste your YAML in the input area, click Convert, and then Apply to Editor to load the result. Additional output formats include Python dict, JavaScript object, TypeScript interface, Java POJO, Go struct, and C struct.

Question 15

How do I generate TypeScript interfaces from JSON?

Accepted Answer

Click Convert in theJSON and select 'JSON → TypeScript interface' from the format dropdown. theJSON analyzes your JSON structure and generates typed TypeScript interface definitions, including nested interfaces for sub-objects, typed arrays, optional properties for nullable fields, and union types when array items have mixed types. This runs entirely in your browser with no dependencies — no upload required.

Question 16

How do I convert CSV to JSON online?

Accepted Answer

Click CSV→JSON in theJSON to open the CSV importer. Paste your CSV content, choose the delimiter (comma, semicolon, tab, or pipe), and confirm whether the first row contains headers. Click Convert to parse the CSV into a JSON array of objects, where each row becomes an object keyed by the header names. Click Apply to Editor to load the result directly into the JSON editor. Quoted fields and embedded delimiters are handled correctly.

Question 17

How do I decode a JWT token online?

Accepted Answer

Click JWT in theJSON to open the JWT decoder. Paste your JWT token (the three base64url-encoded parts separated by dots) and click Decode. theJSON splits the token, base64url-decodes the header and payload sections, and displays them as formatted JSON. The metadata bar shows whether the token has expired, the issue time, expiry time, issuer, and subject claims. Click 'Load payload to editor' to send the decoded payload into the main JSON editor for further analysis. All decoding happens entirely in your browser — your token is never sent to a server.

Question 18

How do I unescape a JSON string online?

Accepted Answer

Click Unescape in theJSON to open the String Unescape tool. The current editor content is pre-loaded as input. Choose the escape mode: Auto-detect (tries JSON string, URL, and Unicode automatically), JSON string value (unwraps \"escaped\" quotes), URL-encoded (%7B%7D format), Base64, or Unicode escape sequences (\u0041). Click Unescape to see the decoded result, then Apply to Editor to replace the editor content.

Question 19

Is theJSON completely ad-free?

Accepted Answer

Yes — theJSON is 100% ad-free. There are no banner ads, no pop-ups, no sponsored content, no analytics trackers, and no third-party scripts that collect your data. The tool is a pure client-side static site: all JSON processing happens in your browser, nothing is sent to any server, and no advertisements are displayed. It is free to use with no sign-up required.

Question 20

How do I convert JSON to Java Map String format?

Accepted Answer

Click Convert in theJSON and select 'JSON → Java Map String ({key=value})' from the format dropdown. theJSON converts your JSON into the same string format that Java's Map.toString() (AbstractMap) produces — for example: {name=John, age=30, address={city=London}, tags=[java, dev]}. This is useful when you need to compare or debug Java Map objects that have been logged or serialised as toString output. The reverse direction — 'Java Map toString → JSON' — parses that format back into standard JSON, supporting nested maps, lists, POJOs (ClassName{field=value}), and primitive types.

Format, validate & edit JSON — right in your browser

EDITOR