Free Online Developer & Converter Tools That Just Work
28+ fast, free, and private tools for developers, designers, and IT professionals. Every tool runs 100% in your browser — no data is ever sent to a server. No sign-up required.
28 tools & counting🔐 Encoding & Decoding
Base64 Encode & Decode
Encode text to Base64 or decode Base64 back to text.
URL Encode & Decode
Percent-encode text for URLs or decode encoded URLs.
HTML Entity Encode & Decode
Convert special characters to HTML entities and back.
📋 Data Formatting
JSON Formatter
Format, validate, and minify JSON with syntax highlighting.
Markdown → HTML
Convert Markdown syntax to clean HTML output.
JSON ↔ YAML Converter
Convert between JSON and YAML formats.
JSON ↔ CSV Converter
Convert between JSON and CSV formats. Handles nested objects.
JSON ↔ XML Converter
Convert between JSON and XML formats with attribute handling.
🔑 Security
JWT Decoder
Decode and inspect JSON Web Token headers & payloads.
Hash Generator
Generate MD5, SHA-1, SHA-256, and SHA-512 hashes.
Password Generator
Generate strong, cryptographically random passwords.
🕐 Date & Time
Timestamp Converter
Convert Unix epoch timestamps to human-readable dates and back.
Cron Expression Parser
Parse cron expressions into human-readable schedules with next run times.
🆔 Generators
UUID Generator
Generate random v4 UUIDs ready to copy.
Lorem Ipsum Generator
Generate placeholder text in paragraphs, sentences, or words.
QR Code Generator
Generate QR codes from text or URLs. Download as PNG.
🎨 Design
🔢 Numbers & Units
Number Base Converter
Convert between Binary, Octal, Decimal, and Hexadecimal.
Byte Converter
Convert between Bytes, KB, MB, GB, TB, and PB.
🔤 Text
🛠️ Developer Tools
Regex Tester
Test regular expressions with live matching and capture groups.
Diff Checker
Compare two texts and highlight additions & deletions.
SQL Formatter
Format, beautify, and indent SQL queries instantly.
🗜️ Minifiers
HTML Minifier
Remove whitespace and comments from HTML.
CSS Minifier
Minify CSS by removing whitespace and comments.
JS Minifier
Minify JavaScript code to reduce file size.
🖼️ Image
Image to Base64
Convert images to Base64 data URI strings.
Image Compressor
Compress PNG, JPEG, WebP images up to 80% smaller.
📖 From the Blog
Base64 Encoding Explained: What It Is, How It Works, and When to Use It
Learn why Base64 exists, how the algorithm converts binary to text, and the real-world use cases every developer should know.
Read article →Understanding JWT Tokens: A Developer's Complete Guide
Decode the structure of JSON Web Tokens — headers, payloads, signatures — and learn best practices for authentication.
Read article →Regex Cheat Sheet: The Most Useful Patterns for Developers
A practical reference of regex patterns for emails, URLs, IPs, dates, and more — with explanations and examples.
Read article →SQL Injection Prevention: A Developer's Complete Guide
Learn what SQL injection is, how attackers exploit it, and the proven techniques to prevent it — parameterized queries, input validation, and more.
Read article →HTTP Status Codes Cheat Sheet: Every Code Developers Should Know
A complete reference to HTTP status codes — from 200 OK to 503 Service Unavailable. Learn what each code means and when to use it.
Read article →🛡️ Privacy first. All tools run entirely in your browser. No data is collected, stored, or sent to any server.
Why Developers Choose DevKit's Free Online Tools
DevKit provides a comprehensive suite of free online developer tools built for speed, privacy, and convenience. Whether you need to format JSON data from an API response, decode a JWT token for debugging authentication issues, generate a secure random password, or convert a Unix timestamp to a human-readable date — every tool runs entirely in your browser with zero server calls.
100% Client-Side Processing — Your Data Never Leaves Your Machine
Unlike many online tools that upload your data to remote servers, DevKit processes everything using JavaScript running locally in your browser. This means sensitive data like JWT tokens, passwords, API keys, and configuration files are never transmitted over the network. You can verify this by opening your browser's Network tab while using any tool.
Built for Real Developer Workflows
Every tool is designed to fit naturally into daily development tasks:
- API Development — Format and validate JSON responses, encode/decode Base64 payloads, inspect JWT authentication tokens, generate UUIDs for database records
- DevOps & Infrastructure — Convert between JSON and YAML for Kubernetes manifests and Docker Compose files, parse cron expressions for scheduled jobs, convert Unix timestamps in server logs
- Frontend Development — Minify HTML, CSS, and JavaScript for production builds, convert images to Base64 data URIs, test regular expressions for form validation, convert colors between HEX, RGB, and HSL
- Security & Authentication — Generate SHA-256 and SHA-512 hashes for file integrity verification, create strong random passwords, decode and inspect JWT token payloads and expiration dates
- Content & Documentation — Convert Markdown to HTML for README files and blog posts, generate Lorem Ipsum placeholder text for mockups, compare text differences with a side-by-side diff viewer
No Sign-Up, No Ads Blocking Your Work, No Rate Limits
All 28+ tools are completely free with no account required. Bookmark any tool and use it instantly — there are no paywalls, no "premium tier" features held back, and no artificial usage limits. DevKit is built by developers, for developers.
Keyboard-Friendly & Accessible
Press / to focus the search bar from any page. Use Ctrl+Enter to execute any conversion. Dark mode toggle respects your system preference. Every tool supports one-click copy to clipboard.