Everything in the catalog

Validates and formats JSON and reports syntax errors.

Evaluates a JSONPath expression against JSON and lists the matches.

Evaluates JSONPath expressions against pasted JSON.

Chinese-language JSON validator, formatter and converter.

Edit, run and share Kotlin snippets online without a local setup.

Edit HTML, CSS and JavaScript with a live preview and sharable snippets.

Minifies JavaScript and CSS to reduce file size.

Defines resources and fields, then serves a REST API with generated data for prototypes.

Creates a mock API endpoint and records the requests sent to it.

Web client for connecting to an MQTT broker and subscribing or publishing to topics.

Run Nim code online.

Shows which versions of an npm package match a semantic-version range.

Write, run and share code in over a hundred languages and a few databases.

Tests JSONPath, JSPath or Lodash-style queries against JSON or XML.

Python editor and interpreter that runs scripts in the browser.

Assembles x86 and x64 instructions into machine code bytes.

Compile, run and step-debug C, C++ and other languages with GDB in the browser.

Online editor and runner for PHP, Java, Ruby, Python, Swift and other languages.

Shows the real install and bundled size of an npm package.

Runs Python code online with input support and instant output.

Decodes raw protobuf bytes without a schema and shows the field tree.

Live editor for testing Python regular expressions against sample text.

Generates React Native shadow styles for iOS and Android elevation.

Proposes starter regular expressions from example strings you type, to refine afterwards.