Developer Tools

The core developer toolbox on UtilityBoxHub: 19 fast, dependable utilities for everyday development work — formatting and validating JSON, XML, YAML, SQL, and Markdown; decoding and generating JWTs; testing regex; building and parsing cron schedules; converting Base64, URLs, HTML entities, and timestamps; generating hashes and UUIDs. Every one of them runs entirely in your browser, so nothing you paste — API responses, tokens, secrets, or anything else — is ever uploaded anywhere.

All developer tools

JSON Formatter & Validator

Format, minify, and validate JSON instantly in your browser.

XML Formatter & Validator

Format and validate XML instantly in your browser.

YAML Formatter & Validator

Format, validate, and convert YAML to JSON instantly.

Regex Tester

Test regular expressions with live-highlighted matches and groups.

Markdown to HTML Preview

Preview Markdown as rendered HTML, with a raw HTML view you can copy.

JSON to Python Converter

Generate Python dataclasses from a JSON sample, with types inferred automatically.

JWT Decoder

Decode a JWT's header, payload, and expiry status instantly.

SQL Formatter

Format and beautify SQL queries with Standard SQL, MySQL, and PostgreSQL support.

Cron Expression Parser

Explain a cron expression in plain English and see its next 5 run times.

JSON to TypeScript Converter

Generate TypeScript interfaces from a JSON sample, with types inferred automatically.

cURL to Python/JavaScript Converter

Convert a cURL command into equivalent Python (requests) or JavaScript (fetch) code.

JWT Generator

Build and sign a JWT from a custom header, payload, and secret using HS256.

Cron Expression Generator

Build a valid cron expression using simple field pickers, with a plain-English preview.

Base64 Encode/Decode

Encode text to Base64 or decode Base64 back to text.

URL Encoder/Decoder

Encode text for URLs or decode URL-encoded text back to plain text.

HTML Entity Encoder/Decoder

Encode text to HTML entities or decode HTML entities back to plain text.

Unix Timestamp Converter

Convert between a Unix timestamp and a human-readable date, in local time and UTC.

Hash Generator (MD5, SHA-1, SHA-256, SHA-512)

Generate MD5, SHA-1, SHA-256, and SHA-512 hashes from any text.

UUID/GUID Generator

Generate random UUID v4 / GUID values, one at a time or in bulk.