85+ Free Developer Tools
Free online tools for developers
85 free tools available
No matching tools found. Please try a different keyword.
Format & Encode
JSON Formatter & Validator
Format, validate, and minify JSON with one click. Clear syntax error display.
SQL Formatter
Auto-format SQL queries. Uppercase keywords and auto-indent.
XML Formatter
Format and minify XML. Syntax validation and indentation settings.
Markdown Preview
Real-time Markdown preview. Supports headings, lists, tables, code blocks.
SVG Optimizer NEW
Optimize and minify SVG. Remove comments, metadata, and simplify paths.
CSS Minifier NEW
Minify and beautify CSS code. Shows size reduction percentage.
JS Minifier NEW
Minify and beautify JavaScript. Remove comments and whitespace.
HTML Minifier NEW
Minify and beautify HTML. Remove comments and normalize whitespace.
YAML Validator NEW
Validate and format YAML. Error line display and pretty print.
Format & Encode
Base64 Encoder/Decoder
Encode and decode text as Base64. Full Unicode/multibyte support.
URL Encoder/Decoder
URL encode and decode online. Handles non-ASCII and multibyte URLs.
HTML Entity Converter
Encode/decode HTML special characters as entities. Named and numeric entities.
Image to Base64
Convert images to Base64 data URLs. Drag & drop. Reverse conversion.
Escape/Unescape
Convert/restore backslash escapes. Handles \\n, \\t, \\r special characters.
String Escape/Unescape NEW
String escape/unescape for JavaScript, Python, Java, C, and more.
Text to Binary NEW
Convert text to/from binary, hex, octal, decimal. UTF-8 support.
Text Processing
Character Counter
Count characters, lines, bytes in real-time. Toggle space include/exclude.
Regex Tester
Test regex patterns in real-time. Highlight matches, view capture groups.
Regex Cheat Sheet
Regex syntax reference. Patterns, quantifiers, character classes, lookahead/lookbehind.
Text Diff Checker
Compare two texts, highlight additions/deletions. For code review and docs.
Text Case Converter
Convert to camelCase, snake_case, PascalCase, kebab-case. 10+ conversions.
HTML to Markdown
Convert HTML to Markdown. Headings, lists, tables, code blocks.
Lorem Ipsum Generator
Generate dummy text by paragraph, sentence, word count. Japanese support.
Slug Generator
Generate URL slugs from text. Customize delimiter and max length.
Word & Character Counter NEW
Real-time character, word, sentence, paragraph count. Reading time and keyword density.
Text to HTML NEW
Convert plain text to HTML. Auto-link URLs, line breaks, escape special chars.
Line Sort & Deduplicate NEW
Sort, deduplicate, reverse, number text lines. Text organization tool.
Markdown Table Generator NEW
Create Markdown tables with GUI. Set rows/columns, edit cells, alignment.
Unicode Lookup NEW
Display code point, UTF-8 bytes, HTML entities. String analysis mode.
Regex Generator NEW
Select and combine common regex patterns. Built-in testing.
Data Conversion
YAML to JSON
Convert between YAML and JSON. Easy config file format conversion.
CSV to JSON
Convert between CSV and JSON. Custom delimiter and header settings.
JSON to CSV
Convert JSON to CSV and download. Flatten nested objects.
TOML to JSON
Convert between TOML and JSON. For Cargo.toml and config files.
JSON to TypeScript
Auto-generate TypeScript interface/type from JSON. Nested support.
JSON Path Finder
View JSON as tree, click to get JSONPath. Test path queries.
JSON Schema Validator NEW
Validate JSON against JSON Schema. Detailed validation errors.
Converters
Unix Timestamp Converter
Convert Unix timestamps and dates. Current time and timezone support.
Color Converter
Convert between HEX, RGB, HSL. Color picker and live preview.
Number Base Converter
Convert binary, octal, decimal, hex. BigInt support for large numbers.
Byte Converter
Convert B, KB, MB, GB, TB, PB. Decimal (1000) and binary (1024) modes.
Image Compressor
Compress/resize images in browser. JPEG, PNG, WebP. Adjustable quality.
Aspect Ratio Calculator NEW
Calculate aspect ratios and dimensions. 16:9, 4:3, 1:1 presets included.
JSON Diff Checker NEW
Compare two JSON objects visually. Highlight additions, deletions, changes.
Date/Time Calculator NEW
Calculate date difference, add/subtract time. Days, hours, minutes, seconds.
JSON to Go Struct NEW
Auto-generate Go struct definitions from JSON with json tags.
Markdown to HTML NEW
Safely convert Markdown text to HTML. Live preview.
SQL to JSON NEW
Generate JSON schema from CREATE TABLE, JSON data from INSERT.
Generators
Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-512 hashes in real-time.
UUID Generator
Generate UUID v4 with cryptographically secure random. Bulk (up to 100).
Password Generator
Generate secure passwords. Customize length, characters, strength meter.
QR Code Generator
Generate QR codes from text/URLs. Custom size, color, PNG download.
Color Palette Generator
Generate harmonious color palettes. Complementary, analogous, triadic.
Placeholder Image Generator NEW
Generate placeholder images in any size. Custom colors and download.
Favicon Generator NEW
Generate favicons from text or emoji. PNG download.
Test Data Generator NEW
Bulk generate random test data. Names, emails, addresses, phones, dates.
Docker Compose Generator NEW
Generate docker-compose.yml from service templates.
Nginx Config Generator NEW
Generate Nginx configs for reverse proxy, SPA, static files, and more.
.env Generator NEW
Generate .env files from framework templates. Auto-generate secrets.
CSS & Design
CSS Gradient Generator
Visually create linear and radial gradients. Add color stops and export CSS.
Box Shadow Generator
Intuitively set box-shadow with sliders. Multiple shadows and inset supported.
Flexbox Playground
Interactively adjust Flexbox properties. Live preview for layout confirmation.
Border Radius Generator
Set border-radius for each corner with sliders. Link/unlink toggle.
CSS Grid Generator NEW
Build CSS Grid layouts visually. Set rows, columns, gaps, and export CSS.
CSS Animation Generator NEW
Create CSS keyframe animations visually. Intuitive controls with live preview.
CSS Unit Converter NEW
Convert between CSS units: px, rem, em, vw, vh, %. Customizable base values.
CSS Selector Tester NEW
Test CSS selectors against HTML. Highlight matching elements.
Image & Media
Image Compressor Popular
Compress and resize images in the browser. JPEG, PNG, WebP output. Adjustable quality.
Placeholder Image Generator NEW
Generate placeholder images of any size. Customizable background/text colors and download.
Favicon Generator NEW
Create favicons from text or emoji. Download as PNG format.
QR Code Generator
Generate QR codes from text or URLs. Customizable size, color, and PNG download.
Development
JWT Decoder
Decode JWT tokens to view Header, Payload, and Signature. Expiration check included.
JWT Generator NEW
Generate JWT tokens from custom header and payload. HS256 algorithm supported.
Cron Expression Parser
Parse cron expressions with human-readable descriptions and next execution times.
Crontab Generator NEW
Create cron expressions with an intuitive GUI. Presets and next execution time preview.
Chmod Calculator
Convert file permissions between numeric (755) and symbolic (rwxr-xr-x) notation.
HTTP Status Codes
Searchable reference of all HTTP status codes. Category filters included.
.gitignore Generator
Generate .gitignore from language/framework templates. Multi-select and customization supported.
IP Address Calculator NEW
IPv4 subnet calculation, CIDR notation conversion, and network information display.
cURL Converter NEW
Convert cURL commands to Python, JavaScript (fetch), PHP, Go, and more.
AI Token Counter NEW
Estimate token counts for GPT-4, Claude, and other LLMs. Character and word counts included.
HTML Preview NEW
Live preview of HTML/CSS/JS. Safe execution in a sandbox environment.
OpenAPI/Swagger Editor NEW
Edit and validate OpenAPI 3.0 specs. Visual endpoint listing.
HTTP Header Viewer NEW
HTTP header reference, builder, and analyzer tool.
DNS Lookup NEW
DNS record type reference and zone file builder.
SEO
Meta Tag Generator
Generate SEO, OGP, and Twitter Card meta tags with a form. Character count validation included.
OGP Preview
Preview OGP settings. View cards as they appear on Facebook, Twitter, Slack, and LINE.
OGP Tester NEW
Validate and test OGP meta tags. Image size recommendations, character count checks, and SNS previews.
Robots.txt Generator NEW
Generate robots.txt with a GUI. Crawler-specific rules and AI bot block presets.