Free online developer tools that stay out of your way
Format JSON, decode Base64, test regex, convert timestamps, transform colors, and handle common developer chores in seconds. No sign-up. No bulky app install. Most tools run entirely in your browser.
JSON Formatter
Format, validate, and beautify JSON data with syntax highlighting.
Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 strings instantly.
URL Encoder / Decoder
Encode or decode URL components for safe transmission.
UUID Generator
Generate random UUIDs (v4) with one click. Bulk generation supported.
Markdown Preview
Write Markdown and see the rendered HTML preview in real time.
Hash Generator
Generate SHA-256, SHA-512, SHA-1 hashes using the Web Crypto API.
Regex Tester
Test regular expressions with real-time highlighting and group extraction.
Timestamp Converter
Convert between Unix timestamps and human-readable dates instantly.
Color Converter
Convert HEX, RGB, and HSL colors instantly with live preview and copy actions.
JWT Decoder
Decode JWT headers and payload claims instantly in your browser.
Diff Checker
Compare two text blocks line by line and inspect additions and removals.
Password Generator
Create secure random passwords with custom length and character groups.
Case Converter
Convert text into uppercase, lowercase, camelCase, snake_case, and more.
Lorem Ipsum Generator
Generate placeholder paragraphs, sentences, and words for layouts and mockups.
Slug Generator
Convert titles and phrases into clean URL-friendly slugs.
Cron Parser
Explain cron expressions field by field and inspect common schedules.
HTML to Markdown
Convert common HTML content into readable Markdown instantly.
CSV to JSON / JSON to CSV
Convert between CSV and JSON data formats instantly. Supports custom delimiters.
HTML Entity Encoder / Decoder
Encode special characters to HTML entities and decode them back. Prevent XSS.
Text to Binary / Hex
Convert text to binary, hexadecimal, decimal, and octal — or reverse any format.
YAML to JSON
Convert between YAML and JSON configuration formats instantly in your browser.
SQL Formatter
Beautify and indent SQL queries for better readability. Supports SELECT, INSERT, UPDATE, and DELETE.
Why developers choose DevToolbox
Built for the way developers actually work — fast lookups, quick conversions, and zero friction.
100% browser-based
Your data stays on your machine. No server uploads, no accounts, no tracking of what you paste or convert.
Fast and focused
Each tool does one thing well. No bloated Swiss-army-knife apps — just the utility you searched for, ready instantly.
Always free
Core developer tools should not cost money. Every tool in the box is free to use with no usage limits.
Popular workflows
Jump into common development tasks with the right tool already loaded.
Debug API payloads
Format JSON responses, decode Base64 payloads, and verify URL-encoded request parameters.
Ship frontend UI faster
Convert colors, preview Markdown docs, and generate IDs without leaving the browser.
Test strings and dates
Validate regex patterns, compare timestamps, and inspect hash output during debugging.
Frequently asked questions
These answers also help communicate privacy, pricing, and product scope more clearly.
Do these tools send my data to a server?+
Most DevToolbox utilities run entirely in your browser. If a future tool requires a network request, that page should clearly say so.
Can I use DevToolbox on mobile?+
Yes. The tools are responsive and designed to work on both desktop and mobile browsers for quick checks on the go.
Is DevToolbox free to use?+
Yes. The core toolbox is free. Monetization is planned through ads and optional premium features rather than locking basic utilities.
How often are new tools added?+
New tools are added regularly based on what developers search for most. Check back often or bookmark the homepage to stay up to date.
Built with transparency in mind
Learn how DevToolbox works, what data it handles, and how your privacy is protected.