Developer Tools
Your practical digital toolkit
Free tools for the work you do every day.
Format code, calculate values, convert units, clean text, build web metadata, and generate useful details—without hunting through a dozen different sites.
Try: format JSON, calculate percentage, convert kg to lb, generate password
50 free tools7 organized collections4 languages
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One place for the tools you reach for.
Developer ToolsUtilities for formatting, checking, converting, and inspecting development data.→CalculatorsClear calculators for percentages, finance, dates, and everyday decisions.→ConvertersPractical unit converters for length, temperature, storage, time, and more.→Text ToolsFast text utilities for counting, cleaning, comparing, sorting, and generating copy.→Web & SEO ToolsCreate web metadata, crawl files, sitemaps, and campaign URLs with transparent output.→Color ToolsConvert color values and check accessible contrast before you publish.→GeneratorsCreate random values for practical digital tasks.→
The tool library
All free tools
Browse the complete ToolboxShelf collection, grouped around the work you actually need to do.
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Developer Tools
JSON Validator
Validate JSON syntax and get clear error messages to fix malformed data fast.
Developer Tools
JSON Minifier
Remove whitespace and compress JSON to shrink payloads while keeping the same data structure.Developer Tools
JSON ↔ CSV Converter
Convert structured record data between array-style JSON and CSV tables for import, export, and analysis.Developer Tools
JSON ↔ YAML Converter
Convert simple JSON documents to YAML and back, maintaining structure and readable output.Developer Tools
Base64 Encoder / Decoder
Encode text into Base64 or decode Base64 strings back to readable text for inspection and handling.Developer Tools
URL Encoder / Decoder
Percent-encode or decode URL components so links and query strings are safe and human-readable.Developer Tools
HTML Encoder / Decoder
Escape HTML special characters to entities or convert entities back into markup to view original content.Developer Tools
UUID Generator
Generate random UUID v4 identifiers suitable for unique keys, test records, and identifiers.Developer Tools
JWT Decoder
Decode JWTs to reveal header and payload claims, timestamps, and contents for inspection.Developer Tools
Regex Tester
Run regular expressions on sample text to view matches, captured groups, and replacements for pattern development.Developer Tools
Timestamp Converter
Convert Unix epoch timestamps to human-readable dates and back, with timezone context for clarity.Calculators
Percentage Calculator
Calculate percentages, percentage change, and ratios for finance, analytics, and everyday math tasks.Calculators
Discount Calculator
Find discount amounts and final prices from original cost and discount percent for clear price comparisons.Calculators
Profit Margin Calculator
Calculate profit margin, markup, and profit based on cost and selling price to assess product profitability.Calculators
ROI Calculator
Estimate ROI percentage and net return using investment cost and net gain to assess performance quickly.Calculators
Simple Interest Calculator
Calculate simple interest, total interest earned or owed, and final amount from principal, rate, and time inputs.Calculators
Compound Interest Calculator
Project investment or savings growth with compound interest, including frequency and time controls for detailed forecasting.Calculators
Loan / EMI Calculator
Estimate monthly EMI payments, total interest paid and overall loan cost from amount, rate and tenure inputs.Calculators
Age Calculator
Compute exact age in years, months and days from a birth date, with next birthday and duration details.Calculators
Date Difference Calculator
Calculate the number of days, weeks, months or years between two dates with optional inclusions for scheduling needs.Calculators
Tip Calculator
Calculate tip amounts and split the final bill among people using percentage or custom tip values for quick bill settling.Converters
Length Converter
Convert between meters, kilometers, feet, miles and other length units for travel, design, and measurement tasks.Converters
Weight / Mass Converter
Convert weights between grams, kilograms, pounds, ounces and other units for cooking, shipping, and measurement needs.Converters
Temperature Converter
Convert temperatures between Celsius, Fahrenheit and Kelvin for weather data, recipes, and scientific use.Converters
Area Converter
Convert area units such as square meters, acres, hectares and square feet for land, design, and estimation.Converters
Volume Converter
Convert volumes between liters, milliliters, gallons, cups and other units for cooking, shipping, and industrial needs.Converters
Speed Converter
Convert speeds between km/h, mph, m/s, knots and more for travel, nautical, or scientific comparisons.Converters
Time Converter
Convert between seconds, minutes, hours, days and weeks for clear duration and schedule calculations.Converters
Digital Storage Converter
Convert digital storage units from bytes through KB, MB, GB and TB with options for binary or decimal conversions.Converters
Pressure Converter
Convert pressure between pascals, bar, psi, atm and other units for engineering or scientific use.Converters
Energy Converter
Convert energy and heat units like joules, calories, BTU and kWh for analysis of consumption and output.Text Tools
Word Counter
Count words, characters and sentences and get an estimated reading time to meet length and readability goals.Text Tools
Character Counter
Get precise character counts with and without spaces, plus selection totals for meeting strict limits and specifications.Text Tools
Case Converter
Transform text into uppercase, lowercase, Title Case, snake_case, kebab-case and other naming styles for consistency.Text Tools
Remove Duplicate Lines
Remove duplicate lines while preserving the first occurrence to clean lists and unique-value datasets quickly.Text Tools
Remove Extra Spaces
Trim extra whitespace, collapse repeated spaces and remove blank lines to normalize and tidy text quickly.Text Tools
Text Sorter
Sort text lines alphabetically or reverse them, with options for case sensitivity and duplicates handling.Text Tools
Text Diff Checker
Compare two text blocks to highlight added, removed and changed lines for clear revision and edit tracking.Text Tools
Lorem Ipsum Generator
Generate classic Lorem Ipsum placeholder paragraphs, sentences or words to populate layouts and mockups.
Web & SEO Tools
Meta Tag Generator
Generate properly formatted HTML meta tags such as description, keywords and viewport for page metadata needs.
Web & SEO Tools
Open Graph Generator
Generate Open Graph meta tags for title, description, image and type to control social share previews.Web & SEO Tools
Robots.txt Generator
Create a robots.txt file with allow/disallow rules and sitemap entries to guide crawler behavior and indexing preferences.Web & SEO Tools
Sitemap Generator
Generate an XML sitemap from page URLs with optional priority and change-frequency attributes for indexing guidance.Web & SEO Tools
UTM URL Builder
Append standardized UTM parameters to links with source, medium, campaign and optional term values for tracking consistency.
Color Tools
HEX to RGB Converter
Convert web colors between HEX codes and RGB channel values to match palettes and CSS color declarations.Color Tools
HEX to HSL Converter
Convert HEX color codes to HSL and convert HSL values back to HEX to fine-tune color hue, saturation and lightness.Color Tools
Color Contrast Checker
Check contrast ratio between foreground and background colors against WCAG levels to ensure readable text and accessible design.Generators
Password Generator
Generate strong, customizable passwords with options for length and character types to meet security or policy needs.Generators
Random String Generator
Produce random alphanumeric or symbolic strings with configurable length for test data, tokens and placeholders.Start here
Tools that take work off your plate.
Quick answers for common digital tasks, from structured data and formulas to practical generators.
Developer Tools
JSON Formatter
Format, indent, and validate JSON to produce readable, structured output for debugging and documentation.Open toolDeveloper Tools
UUID Generator
Generate random UUID v4 identifiers suitable for unique keys, test records, and identifiers.Open toolCalculators
Percentage Calculator
Calculate percentages, percentage change, and ratios for finance, analytics, and everyday math tasks.Open toolConverters
Length Converter
Convert between meters, kilometers, feet, miles and other length units for travel, design, and measurement tasks.Open toolText Tools
Word Counter
Count words, characters and sentences and get an estimated reading time to meet length and readability goals.Open toolWeb & SEO Tools
Meta Tag Generator
Generate properly formatted HTML meta tags such as description, keywords and viewport for page metadata needs.Open toolColor Tools
Color Contrast Checker
Check contrast ratio between foreground and background colors against WCAG levels to ensure readable text and accessible design.Open toolGenerators
Password Generator
Generate strong, customizable passwords with options for length and character types to meet security or policy needs.Open toolDeveloper Tools
JSON Validator
Validate JSON syntax and get clear error messages to fix malformed data fast.Open toolDeveloper Tools
JSON Minifier
Remove whitespace and compress JSON to shrink payloads while keeping the same data structure.Open toolDeveloper Tools
JSON ↔ CSV Converter
Convert structured record data between array-style JSON and CSV tables for import, export, and analysis.Open toolDeveloper Tools
JSON ↔ YAML Converter
Convert simple JSON documents to YAML and back, maintaining structure and readable output.Open toolThe ToolboxShelf difference
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