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ToolBox

Free Developer Tools Online

Free online developer tools: JSON formatter, hash generator, Markdown preview, regex tester, and more. Essential utilities for every developer.

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JSON Formatter

Format, validate, and beautify JSON data with syntax highlighting

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#

Hash Generator

Generate MD5, SHA-1, SHA-256 hashes from any input text

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MD

Markdown Preview

Write Markdown and see a live rendered preview side by side

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.*

Regex Tester

Test and debug regular expressions with live matching and highlights

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D

Text Diff Checker

Compare two texts and see the differences highlighted line by line

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JWT

JWT Decoder

Decode and inspect JSON Web Tokens without sending them to a server

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C

Cron Expression Parser

Parse cron expressions and see the next scheduled run times

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CRN

Crontab Generator

Build cron expressions visually with an intuitive interface

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TBL

Markdown Table Generator

Create Markdown tables visually with an interactive editor

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RWX

Chmod Calculator

Calculate Unix file permissions with an interactive chmod builder

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About Developer Tools

All developer tools on ToolBox are completely free and run entirely in your browser. Your data never leaves your device — there are no server uploads, no accounts required, and no usage limits. Whether you're a developer, designer, student, or professional, these tools are built to save you time.