My Toolbox

Free Online Developer Tools & Financial Calculators

JSON formatter, Base64 encoder, mortgage calculator, unit converter and 30+ more tools. 100% client-side, no signup, no data sent to servers.

JSON Formatter
Format, validate, and beautify JSON data
JSONFormatValidate
Base64 Encoder/Decoder
Encode and decode Base64 strings
Base64EncoderDecoder
Timestamp Converter
Convert between timestamp and datetime
TimeDateConverter
Regex Tester
Test and debug regular expressions
RegexTestDebug
URL Encoder/Decoder
Encode and decode URL strings
URLEncoderDecoder
Hash Generator
Generate hash values (MD5, SHA-1, SHA-256)
HashGeneratorSecurity
UUID Generator
Generate unique UUIDs
UUIDGeneratorUnique
Loan Calculator
Calculate loan payments and interest
LoanFinanceCalculator
Amortization Calculator
Calculate amortization schedule and monthly payments
AmortizationLoanFinance
Mortgage Payoff Calculator
Compare payoff strategies and interest savings
MortgagePayoffFinance
Interest Calculator
Calculate compound interest
InterestFinanceCalculator
Currency Converter
Convert between different currencies
CurrencyExchangeConverter
Color Picker
Pick and convert colors in different formats
ColorPickerConverter
Unit Converter
Convert between different units
UnitConversionTool
QR Code Generator
Generate QR codes from text or URLs
QRCodeGenerator
Basic Calculator
Perform basic arithmetic operations
CalculatorMathBasic
Scientific Calculator
Advanced mathematical calculations
CalculatorMathScientific
Mortgage Calculator
Calculate monthly mortgage payments
MortgageFinanceCalculator
Percentage Calculator
Calculate percentages and percentage changes
PercentageMathCalculator
BMI Calculator
Calculate Body Mass Index
BMIHealthFitness
Age Calculator
Calculate age from birth date
AgeDateCalculator
Password Generator
Generate secure random passwords
PasswordSecurityGenerator
Word Counter
Count words, characters, and sentences
Word CounterCharacter CounterText Analysis
Case Converter
Convert text between different cases
Case ConverterText TransformUppercase
Random Number Generator
Generate random numbers
Random NumberNumber GeneratorDice Roller
GPA Calculator
Calculate grade point average
GPA CalculatorGrade CalculatorCollege GPA
Compound Interest Calculator
Calculate compound interest growth
Compound InterestInvestment CalculatorInterest Calculator
Tip Calculator
Calculate tips and split bills
Tip CalculatorGratuity CalculatorBill Splitter
Date Difference Calculator
Calculate days between dates
Date CalculatorDays Between DatesDate Difference
Calorie Calculator
Calculate daily calorie needs
Calorie CalculatorTDEE CalculatorBMR Calculator
Diff Checker
Compare two texts and find differences
Diff CheckerText CompareCompare Text
Markdown Editor
Write and preview Markdown in real time
Markdown EditorMarkdown PreviewMarkdown to HTML
JWT Decoder
Decode JWT header, payload, and expiration
jwttokendecode
JSON to TypeScript
Generate TypeScript types from JSON
jsontypescriptinterface
Cron Expression Parser
Explain cron schedules and next run times
croncrontabschedule
YAML Formatter
Format, validate, and convert YAML
yamlformattervalidator
XML Formatter
Format, minify, and validate XML
xmlformattervalidator
HTML Entity Encoder
Encode and decode HTML entities
htmlentityencoder
CSS Minifier
Minify or beautify CSS code
cssminifierbeautifier
SQL Formatter
Format and beautify SQL queries
sqlformatterbeautifier
User-Agent Parser
Parse and analyze User-Agent strings
user-agentparserbrowser
HTTP Status Code Lookup
Look up HTTP status codes with descriptions and use cases
httpstatus coderesponse
Image Resizer
Resize images to any dimension
Image ResizerResize ImagePhoto Resizer
Image Compressor
Compress images without losing quality
Image CompressorCompress ImageReduce Image Size
Time Zone Converter
Convert time between time zones
Time Zone ConverterWorld ClockTime Difference
Salary Calculator
Convert salary between pay frequencies
Salary CalculatorHourly to AnnualPay Converter
Budget Planner
Plan and track your monthly budget
budgetplannerexpense
Savings Goal Calculator
Calculate savings needed to reach your goal
savingsgoalcalculator

What Is My Toolbox?

My Toolbox is a collection of 22 browser-based utilities built for people who'd rather get things done than hunt for the right app. Every tool runs entirely in your browser — your data never leaves your device, and there's nothing to install or sign up for.

We started this project in 2024 after getting tired of ad-heavy "free" tools that upload your JSON configs or passwords to unknown servers. The result: fast, private utilities that work offline once loaded. No tracking pixels, no email gates, no upsells.

A Note From the Developer

Why I Built This Site

My Toolbox is a solo project. I'm an independent developer who builds browser-based utilities in my own time, and I run this site because I got tired of the same trade-off showing up on every online tool: sign up, watch ads with modal popups, or paste your data into a page that quietly logs everything server-side. When you're decoding a production JWT or checking a loan calculation with real numbers, none of those are acceptable.

Every tool here is a plain React component that computes results inside your browser. The Vercel edge servers only serve static HTML, CSS, and JavaScript files. After a page loads, nothing you type is sent anywhere — you can verify this yourself by opening DevTools > Network while using any tool. Financial and health calculators document the formulas they use (WHO 2000 BMI thresholds, Mifflin-St Jeor for calories, standard amortization for mortgages) so you can double-check the math, not just trust a black box.

I update tools when I find bugs, when users email me about edge cases, and when the underlying standards change. If a tool has a known limitation, it's written in the tool's own page — not hidden in fine print. Feedback is genuinely welcome through the contact page.

Developer Tools

Format JSON with trailing-comma detection, encode Base64 for JWT debugging, generate SHA-256 hashes for file integrity checks, or test regex patterns with real-time highlighting. Built by developers who use these tools daily — so edge cases like 50 MB JSON files and multi-line regex are handled properly.

Financial Calculators

Run mortgage scenarios with extra-payment comparisons, calculate compound interest with the Rule of 72, or convert currencies using mid-market rates. Every calculator shows the formula it uses and lets you export results — no black-box math.

Converters & Utilities

Convert units across 10 categories, pick colors in HEX/RGB/HSL, generate QR codes up to 4,296 characters, or calculate BMI with WHO classification. Each tool is keyboard-accessible and works on mobile without layout shifts.

Why People Use My Toolbox

100% Client-Side Processing

Your data stays in your browser. We don't send anything to a server — check the Network tab yourself. No cookies, no analytics, no fingerprinting.

Actually Free, No Catch

No freemium limits, no "sign up to unlock" walls, no ads. The site costs us about $12/month to host on Vercel, and we're fine with that.

Zero Registration Required

Bookmark it, use it, close it. We don't need your email, and we won't ask for it. Ever.

Sub-Second Load Times

Static pages served from edge CDN nodes in 30+ regions. Typical first-paint under 400ms on 4G. No client-side framework hydration blocking your input.