💻 Free Online Developer Tools
Essential utilities for developers — JSON formatter, Base64 encoder, regex tester, hash generator, and more. All tools run in your browser with no server uploads.
Every developer needs a toolkit of reliable utilities. Our developer tools cover the full workflow: format and validate JSON, encode/decode Base64 and URLs, generate UUIDs and secure passwords, test regular expressions, minify CSS, convert timestamps, and preview Markdown. All tools process data entirely in your browser — no data is ever sent to our servers. Whether you're debugging an API response, generating test data, or preparing code for production, these free online developer tools save you time and keep your data private.
JSON Formatter
Format, validate, and beautify JSON with syntax highlighting and collapsible tree view. Minify to a single line for production. Catches syntax errors with line numbers.
Base64 Encoder/Decoder
Encode text to Base64 and decode Base64 back to readable text. Works with standard Base64 and URL-safe variants. Quick way to embed data in URLs or decode API responses.
URL Encoder/Decoder
Encode special characters in URLs and decode percent-encoded strings back to normal text. Handles full URLs or individual components. Essential for working with query parameters and form data.
Hash Generator
Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes from any text. Also supports MD5 for legacy checks. Compare two hashes side by side to verify file integrity.
UUID Generator
Generate random UUID v4 identifiers. Click to copy, generate multiple at once with separator options. Good for database keys, test fixtures, or any time you need a unique ID.
Regex Tester & Converter
Test regular expressions, replace with regex, extract matches, and generate code snippets for 10 programming languages.
CSS Minifier
Minify CSS by stripping whitespace, comments, and unnecessary characters. Also beautifies minified CSS back to readable format. Paste your stylesheet and toggle between compact and readable.
Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and vice versa. Supports seconds and milliseconds. Shows UTC and local time side by side. Pick a date to get its timestamp.
Password Generator
Generate strong random passwords with adjustable length and character sets — uppercase, lowercase, numbers, symbols. Shows estimated strength. One click to copy or regenerate.
HTML Entity Encoder
Encode special HTML characters to entities and decode entities back to plain text. Covers all named entities plus numeric codes. Paste raw HTML to escape it for safe embedding.
Markdown Preview
Write Markdown on the left, see formatted HTML on the right. Live preview updates as you type. Supports GitHub-flavored Markdown including tables, code blocks, and task lists.
Text Diff Checker
Compare two pieces of text side by side and see exactly what changed. Highlights additions, deletions, and modifications. Drop in old and new versions to spot edits.
Color Converter
Convert colors between HEX, RGB, HSL, and HSV formats. Adjust with sliders and see a live color preview. Copy CSS-ready values. Pick from a color wheel or paste any valid color.
Number Base Converter
Convert numbers between binary, octal, decimal, and hexadecimal. See all four bases at once when you type a number in any format. Includes hex color reference.
Frequently Asked Questions
Are these developer tools safe for sensitive data?
Yes — all our developer tools run locally in your browser. Your JSON, code, and passwords never leave your device. No data is uploaded to our servers, making these tools safe for debugging production data and generating secure credentials.
What developer tools are included?
Our developer toolkit includes JSON formatter/validator, Base64 encoder/decoder, URL encoder/decoder, hash generator (MD5, SHA-1, SHA-256), UUID generator, regex tester, CSS minifier, Unix timestamp converter, password generator, HTML entity converter, Markdown preview, text diff checker, color converter, and base converter. All are free to use.
Do I need to install anything?
No installation required. All tools work directly in your browser. Just open the tool and start using it — perfect for quick debugging sessions or when working on machines where you can't install software.