Free JSON tools online — runs in your browser

Format, convert,and diff JSON —without leaving your browser.

Fast. Private. No uploads.

example.json

{
  "tool": "jsonic",
  "version": "1.0.0",
  "features": [
    "format",
    "validate",
    "diff"
  ],
  "private": true,
  "latency": 0
}

01JSON FormatterFormat, validate, minify, inspect, and download JSON. Tree view, line numbers, file upload.formattervalidatorminifier→02JSON to TypeScriptGenerate TypeScript interfaces from JSON, including nested objects, arrays, and union types.interfacetypesschema→03JSON to CSVConvert JSON arrays into CSV, flatten nested objects, copy, or download the result.csvflattenexport→04JSON to YAMLConvert JSON to YAML format. Supports nested objects, arrays, and all JSON types.yamlconvertconfig→05CSV to JSONConvert CSV to a JSON array. Handles quoted fields, type coercion, and download.csvimportarray→06JSON DiffCompare two JSON objects with structural diff, line numbers, and inline highlights.comparediffchanges→07JSON to TOMLConvert JSON to TOML format. Nested objects become tables, arrays of objects become array tables.tomlconfigconvert→08JWT DecoderDecode and inspect JWT tokens. View header and payload instantly — your token never leaves the browser.jwttokendecode→09Base64 Encode / DecodeEncode text to Base64 or decode Base64 back to text. Supports Unicode. Swap input and output in one click.base64encodedecode→10URL Encode / DecodePercent-encode strings for use in URLs, or decode them back. Handles all special characters.urlpercent-encodedecode→11JSON Schema ValidatorValidate a JSON document against a JSON Schema. Checks types, required fields, formats, and constraints.schemavalidatedraft-07→12JSONPath TesterEvaluate JSONPath expressions on JSON. Supports wildcards, recursive descent, array slices, and filter expressions.jsonpathqueryfilter→13JSON to XMLConvert JSON to well-formed XML. Handles nested objects, arrays, and null values with proper escaping.xmlconvertelements→14XML to JSONConvert XML to formatted JSON. Repeated sibling elements automatically become JSON arrays.xmlparseconvert→15JSON Escape / UnescapeEscape strings for use inside JSON values, or unescape JSON string sequences back to readable text.escapeunescapestring→16JSON RepairFix broken JSON automatically. Handles trailing commas, single quotes, comments, Python literals, and unquoted keys.repairfixbroken→17JSON Schema GeneratorGenerate a JSON Schema from any JSON example. Infers types, detects formats, adds required fields. Draft-07 and 2020-12.schemageneratedraft-07→18JSON Flatten / UnflattenFlatten nested JSON to dot-notation keys or unflatten a flat object back to nested. Custom delimiter support.flattenunflattendot-notation→19JSON to Zod SchemaGenerate Zod schema from JSON. Produces z.object(), z.array(), .nullable(), and z.infer<> type exports.zodtypescriptschema→20JSON to PydanticGenerate Pydantic v2 BaseModel classes from JSON. Infers Python types, handles Optional, List, and nested models.pydanticpythonfastapi→21JSON to Go StructGenerate Go struct definitions from JSON with json tags, pointer types for null fields, and int64/float64.golangstructserde→22JSON to Rust StructGenerate Rust structs with serde Serialize/Deserialize derives, Option<T> for nulls, and Vec<T> for arrays.rustserdestruct→23JSON to C# ClassGenerate C# classes with [JsonPropertyName] attributes, nullable types, and List<T> for System.Text.Json.csharpdotnetclass→24JSON to Kotlin Data ClassGenerate Kotlin data classes with @JsonProperty annotations, nullable types, and camelCase field names.kotlinandroidjackson→25JSON to Mongoose SchemaGenerate Mongoose schema definitions from JSON with type annotations, required fields, and model export.mongoosemongodbnodejs→26JSON to Java POJOGenerate Java POJO classes with Jackson @JsonProperty annotations, getters, setters, and List<T> for arrays.javajacksonpojo→27JSON to Swift CodableGenerate Swift structs conforming to Codable with CodingKeys, optional types, and nested struct definitions.swiftcodableios→28JSON to PHP ArrayConvert JSON to PHP associative array syntax with proper escaping, nested arrays, and all PHP types.phparrayassociative→29JSON to SQL INSERTGenerate SQL INSERT statements from JSON arrays with CREATE TABLE schema suggestion and NULL handling.sqlinsertdatabase→30JSON to Ruby ClassGenerate Ruby classes with attr_accessor, initialize, from_json, to_h, and to_json methods from JSON.rubyrailsclass→31JSON to Dart ClassGenerate Dart model classes with fromJson factory constructor and toJson method for Flutter projects.dartflutterfromjson→32JSON to GraphQL SchemaGenerate GraphQL SDL type definitions from JSON. Infers non-null fields, nested types, and List types.graphqlsdlschema→

Free JSON tools online — no signup, no upload

Jsonic bundles the everyday JSON utilities developers reach for — formatter, validator, converter, diff, JWT decoder, Base64, and URL encode — into one fast, browser-based site. Many alternatives are slow, cluttered, or force you into upload-heavy workflows. Jsonic keeps common developer tasks local, fast, and focused.

Privacy-first by default

Formatting, conversion, and diffing run entirely in the browser. Your JSON stays on your machine unless you choose to copy it elsewhere — no servers, no telemetry, no accounts.

Guides & References

What is JSON?JSON data types, syntax rules, how it differs from JavaScript objects, and parsing in any language.JSON Syntax ReferenceComplete syntax guide: strings, numbers, booleans, null, objects, arrays, and common errors with fixes.Fetch JSON in JavaScriptUse fetch() to GET and POST JSON: async/await patterns, error handling, and Node.js support.Base64 Encode & Decode in JavaScriptbtoa/atob, Node.js Buffer, Unicode handling, data URIs, and HTTP Basic Auth with code examples.How to Validate JSON OnlineCommon syntax errors, how to fix them, and the difference between syntax and schema validation.JSON.stringify TutorialPretty printing, replacer functions, toJSON behavior, circular references, and serialization pitfalls.JavaScript Object to JSONConvert JavaScript objects into JSON strings safely with replacers, formatting, and edge-case handling.Pretty Print JSON in JavaScriptFormat JSON with indentation in browsers, Node.js, debugging workflows, and formatter tools.Read a JSON File in JavaScriptrequire(), fs.readFileSync, fs.promises.readFile, dynamic import, and fetch — with error handling.JSON.parse in JavaScriptParse JSON safely with try/catch, reviver functions, localStorage handling, and validation checks.JSON to JavaScript ObjectConvert JSON strings into JavaScript objects safely with parsing, revivers, and validation.Parse Nested JSON in JavaScriptRead deep object and array values safely after parsing nested JSON payloads.JSON.parse Error in JavaScriptFix trailing commas, single quotes, comments, escapes, and malformed JSON input.JSON vs XMLCompare APIs, documents, schemas, readability, verbosity, and migration tradeoffs.YAML vs JSONCompare config readability, comments, strictness, indentation risk, and tooling fit.JSON to TypeScript InterfacesHow automatic type inference works — optional fields, unions, nested objects, and null handling.CSV vs JSONFlat tables vs structured objects, spreadsheet exports, API payloads, and conversion tradeoffs.JSON to CSV TutorialFlatten JSON arrays into spreadsheet-ready rows and columns with headers and escaping.CSV to JSON TutorialConvert CSV rows into JSON objects while handling headers, quoted fields, and types.How JWT WorksJWT anatomy: header, payload, signature, base64url encoding, HS256 vs RS256, and verification.How to Decode a JWT TokenThe three parts of a JWT, what each contains, and when to decode for debugging auth flows.JSONPath Cheat SheetComplete syntax reference with examples: wildcards, slices, recursive descent, filter expressions.JSON vs YAMLSyntax differences, side-by-side comparison, and when to use each format.JSON to YAML TutorialConvert JSON into readable YAML for configs and manifests while preserving types.TOML vs YAMLReadable config formats compared: type safety, nesting, comments, and ecosystem fit.JSON to TOML TutorialMap JSON objects to TOML key-values, tables, and array tables for config files.TOML vs JSONConfig format tradeoffs: comments, strictness, nested tables, browser support, and migration tips.JSON vs BSONText interchange vs binary document storage for APIs, MongoDB, dates, ObjectIds, and debugging.JSON vs NDJSONSingle JSON documents compared with newline-delimited records for logs, streams, and imports.JSON Schema TutorialValidate JSON structure with schemas — type, required, enum, pattern, format, and composition keywords.JSON Schema ExamplesCopy-paste schema snippets for required fields, enums, arrays, objects, and common validation rules.JSON Schema Required FieldsUse required correctly for objects, nested objects, arrays of objects, optional values, and common errors.JSON Schema EnumRestrict allowed values with string enums, nullable enums, array item enums, and const patterns.Base64 Encoding ExplainedHow Base64 works, why it exists, and where you encounter it — JWTs, data URIs, HTTP auth.Parse JSON in Pythonjson.loads(), json.load(), error handling, type mapping, nested access, and file reading.JSON ExamplesObjects, arrays, nested structures, API responses, config files, and all JSON data types.JSON Array TutorialArray syntax, arrays of objects, nested arrays, and element access in JavaScript and Python.JSON Object TutorialKey-value pairs, nested objects, property access, iteration, and common API patterns.JSON to XML TutorialConvert JSON objects, arrays, and nulls to well-formed XML with examples.XML to JSON TutorialMap XML elements, repeated tags, and nested structures to JSON objects and arrays.URL Encode & DecodePercent encoding explained: safe characters, JavaScript and Python examples, and common mistakes.