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Data helper

JSON Formatter

Format, minify, and validate JSON instantly by pasting your data.
Pretty-print JSON with consistent indentation or minify it to reduce size, then copy the output with a single click.

This tool helps you quickly detect syntax errors and verify JSON structure, making it ideal for debugging API responses, configuration files, and test data.
Clear formatting improves readability, while minified output is useful
for transmission and storage.

All processing is performed directly in your browser.
No JSON data is sent to any server, ensuring a fast and secure experience
for developers and anyone working with structured data.

Guide: How to use & features

  • Paste JSON into the input area and click Format or Minify to see the result.
  • If parsing fails, an error message with a line number helps you fix it quickly.
  • Copy or download the formatted output to share with scripts or teammates.
  • All operations run locally—no data is uploaded.

Samples: Sample input & output

Pretty-print JSON

Input

{"name":"Taro","age":28,"active":true}

Output

{
  "name": "Taro",
  "age": 28,
  "active": true
}

FAQ: FAQ

  • When should I format versus minify?

    Formatting adds indentation and line breaks to make JSON readable, which suits review and debugging. Minifying strips whitespace to shrink the size, useful when you want to reduce payload size for API calls or storage. Neither changes the underlying data.

  • What are the most common JSON syntax errors?

    The usual culprits are a trailing comma, single quotes on keys or strings (JSON allows only double quotes), unquoted keys, and comments (// or /* */). Standard JSON does not support comments, so for config files you need a different spec such as JSON5 or JSONC.

  • Is it safe to paste large or sensitive JSON?

    All processing happens in your browser and your JSON is never sent to a server, so internal configs and API responses are safe to inspect. Very large inputs may take a moment to format.

Use cases: Common use cases

  • Formatting API responses

    Pretty-print nested payloads so reviews and debugging sessions are easier to follow.

  • Minifying before embedding

    Shrink JSON for query parameters or code snippets to avoid hitting length limits.

  • Catching syntax issues quickly

    Spot trailing commas or missing quotes the moment you paste the payload.

Notes: Notes & limitations

  • Work stays in your browser

    Inputs and outputs remain local. Closing the tab or clearing cache will remove any temporary state.

  • Validate critical data

    Results are helper outputs—double-check them before sending to production systems or sharing externally.

  • Large payloads depend on your device

    Very large text or files can feel slow in some browsers. Use a desktop environment for heavy workloads.

JSON Formatter and Validator

JSON is used everywhere in APIs, configuration files, logs, fixtures, and NoSQL documents, but a single missing comma or quote can break parsing. This browser-based JSON formatter helps you paste JSON, make it readable with indentation, and check syntax errors without sending the data to a server.

Common use cases

  • Inspect API responses: Turn minified JSON into a readable tree-like structure for debugging.
  • Validate configuration files: Catch syntax errors before deploying JSON-based settings.
  • Prepare review snippets: Format JSON before sharing it in issues, pull requests, or documentation.

Things to watch

JSON does not support comments, and values such as "1" and 1 are different types. When you format or validate JSON, also check whether strings, numbers, booleans, arrays, objects, and null match the API or configuration schema you expect.

Articles for this tool

Introduction
2026-05-02

CSV and JSON Conversion: Choosing the Right Format for APIs and Data Migration

Learn how to convert between CSV and JSON safely, including headers, delimiters, value types, nested data, and practical workflow tips.

Introduction
2026-05-02

JSON Formatting and Validation: How to Read API Responses Safely

Learn how to format JSON, catch syntax errors, inspect value types, and turn API responses into types, schemas, or documentation.

Introduction
2026-02-16

The JSON Ecosystem: Connecting Formatting, Types, Validation, and API Specs

Follow one API response through formatting, TypeScript types, Zod runtime validation, and OpenAPI definitions—with real code at every step—for a clear view of type-safe API development.

Use Case
2026-08-07

curl Options Cheat Sheet: What -X, -H and -d Actually Do

A reference for the curl options you meet in real API work: why -d already implies POST, how -d differs from --data-raw, the @ prefix that silently reads a file, single vs double quotes, and why -k and -L deserve more caution than they usually get.

Recent Articles

Use Case
2026-08-07

curl Options Cheat Sheet: What -X, -H and -d Actually Do

A reference for the curl options you meet in real API work: why -d already implies POST, how -d differs from --data-raw, the @ prefix that silently reads a file, single vs double quotes, and why -k and -L deserve more caution than they usually get.

Introduction
2026-08-06

Converting Between JSON Schema and Zod: How required Maps to .optional()

Inside a two-way converter that turns JSON Schema into a Zod schema and Zod code back into JSON Schema. Covers the inverted defaults between required and .optional(), the constraint mapping table, and how the Zod side is parsed without executing any code.

Use Case
2026-08-06

SQL Clause Order Reference: Why WHERE Can't See Your SELECT Alias

The order you write SQL clauses is not the order the database runs them. A reference for the logical execution order (FROM → WHERE → GROUP BY → HAVING → SELECT → ORDER BY → LIMIT), why aliases fail in WHERE, when to use WHERE vs HAVING, and the MySQL/PostgreSQL differences that bite.

Use Case
2026-08-06

Unified Diff Format Reference: Reading @@ Hunks in git diff Output

How to read the unified diff format git produces: what the four numbers in @@ -12,7 +12,9 @@ mean, why a one-character edit shows as a whole-line replacement, the whitespace and line-ending traps, \ No newline at end of file, combined @@@ diffs on merges, and rename detection via similarity index.

Use Case
2026-08-06

UTC to JST Reference: The 9-Hour Offset, Cheat Sheet & Timezone Pitfalls

Convert between UTC and JST (Japan Standard Time) with a cheat sheet. Covers what Z and +09:00 mean in ISO 8601, when JavaScript date parsing silently shifts by 9 hours, MySQL/PostgreSQL timezone behavior, and why GitHub Actions cron always runs in UTC.

Use Case
2026-08-04

CREATE TABLE Reference: MySQL vs PostgreSQL vs SQLite Types & Constraints

A cross-database CREATE TABLE (DDL) reference with cheat sheets for data types, auto-increment keys (AUTO_INCREMENT / IDENTITY / rowid), foreign key ON DELETE behavior, and the CHECK constraint that MySQL silently ignores.

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