{ }jsonkit

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Runs in your browser. Nothing is uploaded.

Free JSON tools online that never upload your data

JsonKit is a JSON toolkit with 76 free tools. Format, validate and convert JSON, create JSON online with a visual editor, or generate types for TypeScript, Go and more. It also handles YAML, CSV, URLs, SQL and jq. No signup, and results update as you type.

Format JSON now →Browse all 76 tools

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jsonkit.com/json-formatter✓ valid · 0.4 ms

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{ "id": "usr_8x42", "name": "Ada Lovelace", "active": true, "roles": ["admin", "editor"], "plan": { "seats": 5 }

76free tools

0 bytessent to any server

0accounts needed

Freeforever

Every JSON tool in one toolkit

Each tool has its own page with sample data already loaded, so you can try it right away.

Format

Beautify or minify JSON with 2 spaces, 4 spaces or tabs./json-formatter

Browse JSON as a collapsible tree, or switch to formatted code./json-viewer

JSON Graph Viewer

See nested JSON as linked nodes you can pan, zoom, search and export./json-graph-viewer

Strip whitespace and line breaks for the smallest valid payload./json-minifier

JSON Escape / Unescape

Turn JSON into an escaped string literal, or unescape a JSON string./json-escape

Sort object keys A to Z or Z to A at every level, or canonicalize with RFC 8785./json-sorter

Flatten nested JSON to dot-path keys, or expand it back./json-flattener

Fix common syntax mistakes and get valid JSON back./json-repair

Mask chosen keys and paths, or find secrets in JSON, YAML, TOML and .env files./json-redactor

Beautify SQL queries for PostgreSQL, MySQL, SQL Server, BigQuery and more./sql-formatter

Clean, sort, filter, dedupe or join CSV tables in one place./csv-editor

XML Validator / Formatter

Check well-formedness and fix indentation without expanding entities./xml-formatter

Normalize layout and scalar styles and keep your comments./yaml-formatter

YAML / Config Merge

Deep-merge a base config with overrides and see every changed path./yaml-merge

Validate

Strict RFC 8259 checks with inline line and column error markers./json-validator

JSON Diff / Compare

See added, removed and changed values in JSON, YAML, XML, TOML or .env files./json-diff

JSON Schema Generator

Generate a draft 2020-12 schema from sample JSON, or validate against one./json-schema-generator

JSON Schema Validator

Check JSON data against a schema and list each problem by path./json-schema-validator

Read the header, payload and signature, with an expiry check./jwt-decoder

JSON Patch / Merge Patch

Generate or apply RFC 6902 JSON Patch and RFC 7386 merge patches./json-merge-patch

JSON Size Analyzer

Count keys, measure depth and find the heaviest paths in a payload./json-size-analyzer

Count LLM tokens as you type, see how text splits, and estimate API cost across 27 models./token-counter

OpenAPI Validator

Check OpenAPI 3.x or Swagger 2.0 structure and local references./openapi-validator

Find malformed rows, broken quoting and duplicate headers./csv-validator

Kubernetes Manifest Validator

Preflight common resources, workload structure and risky settings./kubernetes-manifest-validator

YAML Validator / Linter

Find syntax errors, duplicate keys and risky implicit values./yaml-validator

Convert

Turn table-shaped JSON into spreadsheet-ready rows./json-to-csv

Turn a JSON array into an Excel workbook with one row per object./json-to-excel

Detects the header row and infers value types./csv-to-json

Convert JSON to YAML or YAML to JSON in one place./json-to-yaml

Turn a YAML file into formatted JSON, with anchors resolved./yaml-to-json

Handles attributes, arrays and namespaces./json-to-xml

Turn XML into JSON. Attributes become @_ keys, repeated tags arrays./xml-to-json

JSON to TypeScript

Turn a JSON sample into TS interfaces with nested types and optional fields./json-to-typescript

Base64 Encode / Decode

UTF-8 safe Base64 with a URL-safe option./base64-encode-decode

URL Encode / Decode

Percent-encode a query value or a full URL per RFC 3986, or decode it./url-encode-decode

Timestamp Converter

Convert Unix seconds, milliseconds, ISO 8601 or "now" to readable dates./timestamp-converter

Infer a Zod v4 schema with named schemas for nested objects./json-to-zod

JSON to Pydantic

Infer Pydantic v2 models with nested classes from sample JSON./json-to-pydantic

Typed structs with json tags and optional field detection./json-to-go

Turn sample JSON into Java 17 records or POJO classes./json-to-java

Turn a JSON array into newline-delimited JSON, and back./json-to-jsonl

JSON5 / JSONC to JSON

Strip comments and trailing commas to get strict JSON./json5-to-json

Convert config between JSON and TOML, or validate and format a TOML file./json-to-toml

Number Base Converter

Convert exact integers between binary, octal, decimal and hexadecimal./number-base-converter

Create nullable C# models with nested types and JSON attributes./json-to-csharp

Infer data classes, nullable fields and kotlinx.serialization names./json-to-kotlin

Build nested Rust structs with Option, Vec and Serde derives./json-to-rust

Generate Codable structs with optionals, arrays and CodingKeys./json-to-swift

Create typed PHP 8 DTO classes and JSON key maps./json-to-php

Generate null-safe Dart classes with fromJson and toJson methods./json-to-dart

Split a table by row count, byte size or column value./csv-splitter

CSV ⇄ HTML Table

Create semantic HTML tables or extract them back to CSV./csv-to-html

CSV ⇄ Markdown Table

Create and parse GitHub Flavored Markdown tables./csv-to-markdown

Convert comma-separated and tab-separated tables both ways./csv-to-tsv

Turn a contact spreadsheet into one .vcf file with a vCard per row./csv-to-vcard

XLSX ⇄ CSV / JSON

Move worksheet data between Excel, CSV and JSON on your device./xlsx-converter

Turn a cURL command into Python, JavaScript, PHP, Go, Java, C#, Rust or Ruby code./curl-to-code

Data URI Encoder / Decoder

Create inline data URLs or get back their text and bytes./data-uri-encoder-decoder

.env ⇄ JSON / YAML

Convert .env to JSON or YAML and back, or validate a .env file./env-to-json

INI ⇄ JSON / YAML / TOML

Move sectioned INI data to structured formats and back./ini-converter

Convert config data between YAML 1.2 and TOML./yaml-to-toml

Query & Generate

JSONPath Tester

Run JSONPath queries or JSON Pointers on JSON or YAML as you type./jsonpath-tester

Run real jq 1.8 filters on JSON, with the -r, -c, -s and -S flags./jq-tester

Mock JSON Data Generator

Generate fake records from a field spec, or sample JSON from a JSON Schema./mock-json-generator

UUID / NanoID Generator

Generate UUID v4, UUID v7 or NanoID in batches with the crypto RNG./uuid-generator

Hash text to a hex digest with SHA-256, SHA-1 or MD5./hash-generator

Live matches, named groups and capture details as you type./regex-tester

JMESPath Tester

Try filters, projections, pipes and functions like contains() on JSON or YAML./jmespath-tester

JSON Creator / Editor

Build JSON visually. Add keys, pick value types and nest objects or arrays./json-editor

Cron Expression Parser

Check five-field cron schedules and preview their next runs./cron-expression-parser

Split a URL into its parts, parse a query string to JSON, or build one./url-parser

Infer a table definition and parameterized INSERT examples./csv-to-sql

HTTP Headers Parser

Turn request or response headers into structured JSON./http-headers-parser

MIME Type Lookup

Look up extensions and media types with charset and compression info./mime-type-lookup

Unicode & Encoding Inspector

Show graphemes, code points, bytes and invisible control characters./unicode-inspector

Built for how developers work

∅ zero-upload

Paste production data safely

Tools run in your browser. Once a page has loaded, it keeps working offline.

» instant

Results as you type

No submit buttons. Format, validate and convert live, with errors marked by line and column.

⌨ keyboard-first

Shortcuts everywhere

⌘K to jump between tools, ⌘↵ to run, ⌘C to copy output. You never need a mouse.

↗ shareable

Send a link, not a file

The tool and your input are encoded into the URL. You see a privacy warning before you share.

How JsonKit compares

Compared with the usual ways developers work with JSON.

{ }jsonkit

Typical online tools

CLI (jq, sed…)

IDE plugins

Data stays on your machine

✓ always

✗ often uploaded

✓

✓

Zero install, works anywhere

✓

✓

✗ install + PATH

✗ per-editor

76 tools in one place

✓ one ⌘K away

✗ one site each

~ scriptable

✗ format only

Visual diff & error markers

✓ line + column

~ varies

✗ text output

✓

Shareable result links

✓ URL-encoded

~ rare

✗

✗

Cost

Free

Free, ad-heavy

Free

Free or paid

CLI tools and IDE plugins are great. JsonKit is for when you want an answer in the next five seconds, on any machine.

Frequently asked questions

Is my JSON uploaded anywhere?

No. Every tool runs in your browser with JavaScript, and no server receives your input. Once a tool page has loaded, it keeps working offline.

Are the tools really free?

Yes. All 76 tools are free to use, with no signup and no ads.

What is the maximum file size?

There is no fixed limit. Everything runs on your device, so the practical limit depends on your browser and how much memory is free.

Can I share a result with a teammate?

Yes. The tool and your input are encoded into the URL. You see a privacy warning first, so secrets don't end up in chat logs.