Everything in the catalog

Free REST API returning sample store products, carts and users for demos and front-end practice.

Explores binary layouts of float formats such as half, single, double and bfloat16.

Generates Brazilian postal codes (CEP) for form testing.

Generates syntactically valid CNH driver licence numbers for tests.

Generates valid Brazilian CNPJ company numbers for test data.

Generates valid Brazilian CPF numbers for software testing.

Generates fictional Brazilian company documents (CNPJ, state registration, CEP).

Generates fictional Brazilian person records (name, CPF, RG, address) for testing.

Generates Renavam vehicle registration numbers for testing.

Generates RG identity numbers following SSP-SP format for testing.

Runs and shares code snippets in dozens of languages from the browser.

Opens a file and lets you inspect and edit its bytes in a hex view.

Edits binary files byte by byte in a browser hex editor.

Browser MQTT client for publishing and subscribing against HiveMQ or your own broker.

Tests Apache rewrite rules against a URL and shows which rules matched and the resulting target.

Minifies uploaded HTML files to cut their size.

Sends API calls from a web page: pick a method, add headers and a body, read the response.

Compiles and runs code in 60-plus languages and keeps a shareable paste of the result.

Online IDE that runs code in over a hundred languages, with an optional AI helper.

Edit HTML, CSS and JavaScript side by side with live result and shareable links.

Boots Linux, Windows 2000 or FreeDOS in a PC emulator running in the browser.

Views, edits, formats and queries JSON in a tree and text editor.

Validates JSON against a JSON Schema interactively.

Infers a JSON Schema from a sample JSON document.