Apps
Tools and experiments
Practical apps, built for the web
This is a growing collection of focused tools. Each app opens on its own page and runs directly in your browser.
Compound Interest Calculator
Estimate investment growth with recurring contributions and review balance milestones over time.
Open calculatorMortgage Calculator
Estimate monthly housing costs, total interest, and the remaining loan balance over time.
Open calculatorScientific Calculator
Write and edit formulas with scientific functions, constants, memory, angle modes, and calculation history.
Open calculatorTodo List
Organize categorized tasks privately in your browser, then back them up or restore them with a readable Markdown file.
Open listFocus Interval Timer
Alternate focused work with restorative breaks using customizable durations, rounds, sounds, and automatic transitions.
Start focusingStopwatch & Timer
Measure elapsed time with precise laps or run a configurable countdown with presets and an audible alert.
Open time toolsTime Zone Converter
Type two major cities or regions to compare their live time, date, and UTC offset.
Convert time zonesCalendar
Browse month, week, and hourly day views with common holidays, then print a clean planning page.
Open calendarTouch Typing
Practice a randomly selected short passage, then review your speed, accuracy, errors, and completion time.
Start typingTouch Typing Tutorial
Progress through 100 guided levels, learn the correct finger for every key, and earn stars from detailed results.
Begin lesson oneVim Tutorial
Learn essential Vim movement, editing, search, operators, and commands in a simplified interactive practice editor.
Start Vim trainingKaleidrop
Shape a shifting spectrum with nine compact shards, chain band clears, complete color cycles, and master a wider field.
Play gameCanyon Sprint
Guide a vividly illustrated roadrunner through an ever-faster desert, leaping rocks and ducking beneath canyon hawks.
Start runningMore apps will be added here as they are created.