Top 9 JSON Validation and Formatting Tools Every Developer Should Know

JSON is widely used because it is easy for developers to handle and machines to parse, which has led to a thriving ecosystem of tools for reformatting, validating, and processing JSON data.

JSONLint

JSONLint, created by CircleCell, is an online validator and formatter where users can paste JSON, type a URL, or add ?reformat=compress to compress the output. The tool’s source code is available at https://github.com/circlecell/jsonlint.com.

JSONCompare

JSONCompare, an advanced version of JSONLint, validates JSON directly and supports batch uploading, comparing, and merging of multiple JSON files. It offers simple, batch, and diff modes, and its source code resides at https://github.com/circlecell/jsoncompare.com.

jtc (JSON Test Console)

jtc is a CLI utility that extracts, processes, and transforms source JSON. Users can select one or more elements and apply operations such as wrapping, filtering, or updating, all via a single command. Pre‑compiled binaries for Linux and macOS can be downloaded from https://github.com/ldn-softdev/jtc#compile-and-install-instructions.

ijson

ijson, first released in 2016, provides an iterator‑based JSON parser for Python, supporting C‑based YAJL or pure‑Python back‑ends. It is commonly used to generate native Python objects from streaming JSON. The package can be installed from PyPI at https://pypi.org/project/ijson/#files.

JSON Formatter & Validator

This online tool formats and beautifies JSON to improve readability and debugging. Users paste JSON or provide a URL, and the service can also bookmark public JSON URLs for quick validation. It is accessible at https://jsonformatter.curiousconcept.com/.

Altova XMLSpy

Altova XMLSpy is a commercial JSON and XML editor offering visual schema design, code generation, file conversion, debugging, and support for XSLT, XSD, XBRL, and SOAP. JSON validation is performed via the RaptorXML Server. A free trial can be downloaded from https://www.altova.com/xmlspy-xml-editor/download.

Code Beautify JSON Tools

Code Beautify provides a suite of online utilities including a JSON viewer, editor, validator, and converters to HTML, XML, YAML, as well as an Excel‑to‑JSON converter and a minifier. The full set of tools is available at https://codebeautify.org/json-tools.

Visual Studio Code

Microsoft's Visual Studio Code includes built‑in JSON support with IntelliSense validation, navigation, code folding, and context‑aware suggestions based on associated JSON schemas. The editor can be downloaded from 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, complying with RFC 4627. It can be installed via the Eclipse Marketplace at https://marketplace.eclipse.org/content/json-editor-plugin.