repl.it : Powerful and simple online compiler, IDE, interpreter, and REPL. Code, compile, and run code in 30+ programming languages. including JavaScript, Pytho...
ideone.com : Ideone is an online compiler and debugging tool which allows youto compile source code and execute it online in more than 60 programming languages.
ack : ack is a tool like grep, optimized for programmers
Designed for programmers with large heterogeneous trees of source code, ack is written purely in po...
Quicktype : Quicktype generates types and helper code for reading JSON in C#, Swift, JavaScript, Flow, Python, TypeScript, Go, Rust, Objective-C, Kotlin, C++ and ...
