Create Linux Cron Expressions
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Search through hundreds of common regex patterns for any use case.
Ancient strategy game played with stones
Play Blackjack (21) against the house.
Visualize Audio Frequencies
Test/Create Regex
Interactive ASCII chart
Detect & generate DTMF tones.
Track books you have read, are currently reading, and want to read.
Calculate CVSS v3.1 and v4.0 vulnerability severity scores
Print Calendars
Production, safety, compliance, etc.
Use your own images!
Search the Billboard Hot 100 songs
Minify, obfuscate or beautify your code
Animated Spinner Selector (like Wheel of Fortune)
Look up 585 illustrated words in 12 languages, and hear them spoken.
SSL Checker
Ancient Japanese chess game
Learn and master flag semaphore signals.
Test apps on different display sizes
Expand CIDR ranges, calculate subnets, check IP membership, compare networks, etc.
Plot mathematical functions, explore graphs interactively, and perform analysis.
A free POS / Cash Register app
Calculate simple and compound interest
Create Professional Lead Sheets & Chord Charts
Calculate statistical significance with t-tests, z-tests, chi-square, and correlation analysis.
Make sure you're getting enough sleep!
Many interesting coins to flip
Look up domain registration, DNS records, SSL certs, etc for any domain or IP