9 Essential JSON Validation and Formatting Tools Every Developer Should Know

JSON’s simplicity makes it a favorite for developers and machines alike, but working with raw JSON often requires validation, formatting, and transformation tools. This guide lists nine widely used utilities, covering web‑based services, command‑line programs, IDE extensions, and full‑featured editors.

# JSONLint

JSONLint, provided by CircleCell, is an online validator and formatter. Users can paste JSON, type it directly, or supply a URL. It not only checks for syntax errors but also parses the JSON, and adding ?reformat=compress to the URL compresses the output.

Website: https://jsonlint.com/

Source code: https://github.com/circlecell/jsonlint.com

# JSONCompare

JSONCompare is the advanced version of JSONLint, also from CircleCell. It validates JSON, supports batch uploads, and can compare or merge two JSON objects. Modes include simple, batch, and diff, making it useful for side‑by‑side analysis.

Website: https://jsoncompare.com/

Source code: https://github.com/circlecell/jsoncompare.com

# jtc (JSON Test Console)

jtc is a CLI tool for extracting, processing, and transforming source JSON. It lets users select one or more elements, wrap them into new JSON, filter, or update them, all via a single command. Pre‑compiled binaries are available for Linux and macOS.

Source code: https://github.com/ldn-softdev/jtc#compile-and-install-instructions

# ijson

ijson provides an iterator‑based streaming JSON parser for Python. It can generate native Python objects from a JSON stream below a given prefix, with implementations based on the C‑based YAJL library or a pure‑Python backend.

Download: https://pypi.org/project/ijson/#files

# JSON Formatter & Validator

This online tool formats and beautifies JSON for easier reading and debugging. Users paste JSON or provide a URL; the service also supports bookmarking public JSON URLs for quick validation.

Website: https://jsonformatter.curiousconcept.com/

# Altova XMLSpy JSON and XML Editor

Altova XMLSpy is a commercial editor handling both JSON and XML. It offers modeling, transformation, debugging, and validation features, including JSON validation via the RaptorXML Server.

Download (trial): https://www.altova.com/xmlspy-xml-editor/download

# Code Beautify JSON Tools

Code Beautify provides a suite of JSON utilities: viewer, editor, validator, and converters to HTML, XML, YAML, as well as an Excel‑to‑JSON converter and a minifier. It also supports many other data formats.

Website: https://codebeautify.org/json-tools

# Visual Studio Code

VS Code includes built‑in JSON support with IntelliSense, validation, navigation, code folding, and suggestions. Hovering over properties shows context, and the editor uses associated JSON schemas to understand file structure.

Download: https://code.visualstudio.com/Download

# Eclipse JSON Editor Plugin

The free Eclipse plugin adds custom syntax highlighting, code folding, formatting, and a synchronized tree view for JSON files. It complies with the RFC 4627 JSON standard.

Download: https://marketplace.eclipse.org/content/json-editor-plugin