Free Online Developer Tools

12 free developer tools. No signup required. Works entirely in your browser.

DevStation Pro
All-in-one developer toolkit with encoders, formatters, generators, and debugging tools.
Popular
API Playground
Test REST APIs with custom headers, authentication, and response visualization.
Popular
JWT Debugger
Decode, verify, and debug JWT tokens with payload inspection and signature validation.
JSON Editor
Format, validate, and edit JSON with syntax highlighting, tree view, and error detection.
SQL Formatter
Format and beautify SQL queries with customizable indentation and keyword casing.
Cron Generator
Build cron expressions with visual editor, preview next run times, and expression explanation.
Git Commands
Quick reference for Git commands with examples, explanations, and copy-to-clipboard.
Text Diff
Compare two texts side-by-side with highlighted differences and merge suggestions.
Regex Tester
Test regular expressions live with match highlighting, group capture, and replace mode.
Popular
Hash Generator
Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes for text or files.
Number Converter
Convert between Binary, Octal, Decimal, and Hexadecimal with bitwise operations.
Timestamp Converter
Convert Unix timestamps to human dates and vice versa with multi-timezone support.

About Developer Tools on OneTool

OneTool provides 12 free developer tools that run entirely in your browser. No account, no email, no subscription. Your data stays on your device.

These tools help with: developer tools online free, JSON formatter, JWT decoder, regex tester online, SQL formatter free, API tester browser.

All tools are part of the OneTool suite — a free collection of 60+ utilities for finance, productivity, developer tasks, PDF management, and more.