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.
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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.
Developer Tools
JSON Validator
Check whether your JSON is correctly formatted and ready to use. Paste your data, enter it manually, or upload a .json file to detect syntax errors. You can also provide a JSON Schema to check whether your data follows common structural and value rules.Developer Tools
JSON Minifier
Minify JSON online by removing unnecessary formatting whitespace. Make JSON text more compact, check its syntax before minifying, and optionally sort object keys. View the size reduction, then copy or download the result.Developer Tools
JSON ↔ CSV Converter
Choose a delimiter, work with column headers, flatten nested JSON objects, and preview your data before copying or downloading the result.Developer Tools
JSON ↔ YAML Converter
Convert JSON to YAML or YAML to JSON with an online converter. Validate your input, identify parsing errors, adjust indentation and formatting, sort mapping keys, and copy or download the converted result.Developer Tools
Base64 Encoder / Decoder
Encode text and files to Base64 or decode Base64 data back into readable text or downloadable files. This online Base64 encoder and decoder supports UTF-8 text, URL-safe Base64, optional padding removal, and configurable output line wrapping.Developer Tools
URL Encoder / Decoder
Encode or decode text, URL components, and form values with this free online URL Encoder / Decoder. You can also parse query parameters, edit parameter values, and build an updated URL. Convert text as you type or manually, then copy or download the result.Developer Tools
HTML Encoder / Decoder
Convert special characters into HTML entities or decode HTML entities back into readable text. Encode or decode manually or as you type, preserve existing entities, convert non-ASCII characters, and process nested entities with up to five decoding passes.Developer Tools
UUID Generator
Generate random UUID v4 identifiers suitable for unique keys, test records, and identifiers.Developer Tools
JWT Encoder/Decoder
Decode JWTs, inspect claims, verify HMAC signatures, and generate signed test tokens with HS256, HS384, or HS512.Developer Tools
Regex Tester
Test and debug JavaScript regular expressions. Highlight live matches, inspect capture groups and positions, and preview JavaScript replacements.Developer Tools
Timestamp Converter
Convert Unix timestamps into readable dates, or convert a date and time into a Unix timestamp. This free online Unix Timestamp Converter supports seconds and milliseconds, displays UTC and selected-timezone results, and updates automatically as you change the input.Calculators
Percentage Calculator
Calculate percentages, percentage changes, increases, and decreases with six live calculators that show the formula for each result.Calculators
Discount Calculator
Calculate the final price of an item after discounts, coupons, and sales tax. Enter the original price and quantity, choose a percentage or fixed-amount discount, and optionally apply an additional coupon.Calculators
Profit Margin Calculator
Calculate your profit margin, markup, and profit per item with this free Profit Margin Calculator. Enter your product cost and selling price to see how much profit you make on each sale and how your results change with additional costs and different quantities.Calculators
ROI Calculator
Calculate return on investment, net profit or loss, total return percentage, and estimated annualized ROI.Calculators
Simple Interest Calculator
Calculate simple interest and the final amount using your principal, annual interest rate, and time period. Choose a duration in years, months, or days, select a currency, and see your results update as you change the inputs.Calculators
Compound Interest Calculator
Estimate how your savings or investments may grow over time with compound interest. Enter an initial deposit, annual interest rate, and investment period. You can also add recurring contributions and choose how often they are made and how frequently interest compounds.Calculators
Loan / EMI Calculator
Calculate your estimated monthly loan payment, total interest, and repayment time with this free Loan EMI Calculator. Enter your loan amount, annual interest rate, and repayment term to see how much you may need to pay each month.Calculators
Age Calculator
Calculate your age in years, months, and days from your date of birth, or find your age on any past or future date.Start here
Tools that take work off your plate.
Quick answers for common digital tasks, from structured data and formulas to practical generators.
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