Cybersecurity & developer tools
Free, fast and practical. Most of these run entirely in your browser, so nothing you type is transmitted to us — which matters when the input is a token, a password or production data.
13 tools available · more in progress
Networking
Addressing, subnetting and IP maths
- CIDR CalculatorCalculate network address, broadcast address, usable host range, subnet mask and host count from any IPv4 CIDR block. Runs entirely in your browser.Runs in your browser
- Subnet Mask ConverterConvert between CIDR prefix length, dotted-decimal subnet mask and wildcard mask, with the binary representation of each.Runs in your browser
- IP Address ConverterConvert an IPv4 address between dotted decimal, binary, hexadecimal and 32-bit integer notation, and see how each octet maps to bits.Runs in your browser
Web Security
TLS, headers and browser policy
Developer
Encode, decode, format and inspect
- JWT DecoderDecode a JSON Web Token to read its header, payload and registered claims, with expiry checked against the current time. Nothing leaves your browser.Runs in your browser
- Base64 Encoder / DecoderEncode text to Base64 or decode Base64 back to text, with full Unicode support and a URL-safe variant. Runs entirely in your browser.Runs in your browser
- URL Encoder / DecoderPercent-encode or decode URLs and URL components, with the distinction between full-URL and component encoding made explicit.Runs in your browser
- JSON Formatter & ValidatorFormat, minify and validate JSON with precise error positions, so you can find the exact character where parsing failed.Runs in your browser
Cryptography
Hashing, entropy and secure randomness
- Hash GeneratorGenerate cryptographic hashes using the browser’s Web Crypto API. Your input never leaves the page.Runs in your browser
- Password GeneratorGenerate random passwords using the browser’s cryptographic random number generator, with live entropy measurement.Runs in your browser
- Password Entropy CalculatorCalculate the entropy of a password in bits and see how long an offline attack would take at realistic cracking rates.Runs in your browser
Linux
Permissions, scheduling and the shell
- chmod CalculatorConvert between octal chmod values, symbolic notation and the permission bits Linux actually stores, including setuid, setgid and the sticky bit.Runs in your browser
- Cron Expression GeneratorBuild a cron expression from plain fields, or paste one to see what it means in English and when it next runs.Runs in your browser