Security & Identity
4GUID Generator
v4, v7, v1 & v5 UUIDs
Password Generator
Secure entropy keys
Hash Generator
SHA, MD5, RIPEMD
JWT Debugger
Decode, edit, re-sign
Data & Formatting
9JSON Compare
Compare two JSONs
JSON Formatter
Beautify & validate
JSON Merge
Combine two documents
Base64
Encode & decode
Epoch Converter
Unix timestamp tool
Regex Tester
Regular expressions
YAML ↔ JSON
Convert between formats
SQL Formatter
Clean up queries
JSON → Code
Classes & interfaces
Networking & Backend
4IP Calculator
CIDR & subnetting
cURL Converter
Request to code
HTTP Inspector
Raw request parser
Cron Parser
Schedule humanizer
Algorithms & Concepts
5Sorting Visualiser
Watch five algorithms run
Binary Search Tree
Insert, find, traverse
Pathfinding
BFS, DFS and A*
Big-O Reference
Costs at a glance
Interview Patterns
Recognise, then solve