Welcome to HCODX Online Compiler
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Compile and run Zig code online instantly with HCODX. Our free cloud-based Zig compiler supports real-time execution, standard input, syntax highlighting, and code download. No installation or configuration required. Start coding in Zig now.
Run Zig instantly without installing any IDEs or configuring environments. Our cloud-based Zig handles libraries, runtimes, and dependencies automatically so you can focus on writing code.
Whether you are studying algorithms in Zig, practicing data structures in Zig, or exploring functional programming, our tool provides real-time stdout/stderr feedback with interactive standard input support.
HCODX is a free online compiler and code runner: write code in your browser, execute it on a cloud sandbox, and interact with your program through a live terminal. Students use it for coursework and interview practice; developers use it to test snippets in 85+ languages without setting up a local environment.
Zig is a systems programming language created by Andrew Kelley that pairs manual memory management with modern safety checks and a powerful comptime metaprogramming system. There is no hidden control flow, no preprocessor, and no garbage collector, which is why it powers performance-critical projects like the Bun JavaScript runtime and the TigerBeetle financial database. As of 2025 the language sits in its 0.14/0.15 release series and is still moving toward 1.0, so the fastest way to keep up with breaking changes is to run snippets often. This page compiles and executes your Zig program in a real interactive terminal: build errors and output stream live, and you can type responses to stdin prompts while the process runs, with zero local setup.
const std = @import("std");
pub fn main() !void {
const stdin = std.io.getStdIn().reader();
const stdout = std.io.getStdOut().writer();
try stdout.print("What is your name? ", .{});
var buf: [64]u8 = undefined;
if (try stdin.readUntilDelimiterOrEof(&buf, '\n')) |name| {
try stdout.print("Hello, {s}! Welcome to Zig.\n", .{name});
}
var i: u8 = 1;
while (i <= 3) : (i += 1) {
try stdout.print("{d} squared is {d}\n", .{ i, i * i });
}
}Zig shows up in systems programming and operating systems courses as a cleaner alternative to C, in game and embedded development where allocator control matters, and in tooling teams that use zig cc as a drop-in cross-compiling C toolchain. Students preparing for low-level interviews use it to practice pointers, error unions, and defer-based cleanup, while contributors to projects like Bun and TigerBeetle test small reproductions here before opening issues. It is also a popular playground for exploring comptime, Zig's compile-time code execution feature. HCODX is a free online Zig editor, runner and interpreter — an IDE-grade compiler and playground to write and run code online, execute code with live output and live preview, no downloads or web server required.
Yes. The terminal on this page is a live session, not a form that pre-collects input. When your program calls a reader method such as readUntilDelimiterOrEof on std.io.getStdIn(), execution pauses, the prompt appears in the terminal, and whatever you type is delivered to the process the moment you press Enter.
The sandbox tracks a recent stable release from the 0.x series. Because Zig still makes breaking changes between minor versions, especially around std.io and build APIs, check the compiler error messages if an older snippet fails; they usually name the replacement API directly and the fix is typically a one-line change.
No. The environment compiles a single source file with zig run, so build scripts, multiple modules, and package manager dependencies from build.zig.zon are not available. The entire standard library works normally, which covers allocators, data structures, formatting, math, and everything most exercises and interview problems need.
Your current code will be replaced with the default sample. This cannot be undone — download your code first if you want to keep it.
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