Online Python Compiler
Run Python 3.12 online with the full standard library. Perfect for DSA practice, scripting and interview prep — read stdin with input() and see output in seconds.
Free Online Compiler — Run Python, Java, C, C++, JavaScript, Rust and Go Code Online | Squarebrackets
Python·Sum of N numbers
9 lnAbout the Squarebrackets online compiler
This free online compiler and code runner is built by Squarebrackets, an IT training company. It executes your programs in secure, isolated Docker containers — pick a language, write your code in a real editor with syntax highlighting and auto-indent, pass standard input from the Input tab, and get output in seconds. No account, no installation, no local toolchain.
It's built for students practising DSA, developers testing snippets, trainers running live demos, and anyone preparing for coding interviews — the same environment we use in Squarebrackets classroom labs and training programs.
Languages you can compile online
JavaScript Online Compiler
Execute JavaScript on Node.js 20 (V8). Test snippets, algorithms and console programs without opening DevTools or installing Node on your machine.
Online Java Compiler
Compile and run Java on OpenJDK 21. Scanner-based input works out of the box — write your Main class, pass input, and hit Run.
Online C Compiler
GCC 13 with the C17 standard. scanf/printf, pointers, arrays — everything you need for college labs and systems programming practice.
Online C++ Compiler
GCC 13 with C++20 and <bits/stdc++.h> support — ready for competitive programming, STL practice and coding-round preparation.
Rust Online Compiler
Compile Rust 1.77 with rustc directly in the browser. Try ownership, iterators and pattern matching without setting up a local toolchain.
Go Online Compiler
Run Go 1.22 programs online. Goroutines, slices and the standard library work exactly as they do locally — zero installation required.
Why developers use the Squarebrackets compiler
Instant execution
Code runs in fresh, isolated Docker containers and streams the result back within seconds.
Standard input (stdin)
A dedicated Input tab feeds your program through input(), Scanner, cin, fgets and friends.
Real editor experience
Syntax highlighting, auto-indent, bracket pairing and line numbers — not a plain textarea.
Autosave per language
Your code and input are saved per language in this browser tab, so a refresh never loses work.
7 modern toolchains
Python 3.12, Node 20, JDK 21, GCC 13 (C17 / C++20), Rust 1.77 and Go 1.22.
Works on mobile
A responsive layout with a Code / I-O toggle makes the compiler usable on any phone.