Odin Online Compiler - Run Odin Code in the Browser

Odin calls itself a language for "the joy of programming," and after using it, that tagline actually holds up. It's a C-level systems language built by someone (Bill Hall, aka gingerBill) who got tired of fighting C and C++ while making games.

The language is designed around data-oriented design principles. Instead of class hierarchies and inheritance trees, you work with plain structs and procedures. Data flows through functions. State lives in predictable places. If you've read anything by Mike Acton or watched his "Data-Oriented Design and C++" talk, Odin feels like someone turned those ideas into a language spec.

Setting up Odin locally requires cloning the compiler repo and building it, or grabbing a nightly release. It's not hard, but it's not apt install odin either. For trying out the language or testing a quick idea, an Odin online compiler is the path of least resistance.

Structs, procedures, and nothing hidden

Odin keeps things flat on purpose. No constructors, no destructors, no method overloading. Procedures take data in and return data out. Here's what that looks like in practice:

package main

import "core:fmt"
import "core:math"

Vec3 :: struct {
    x, y, z: f64,
}

vec3_length :: proc(v: Vec3) -> f64 {
    return math.sqrt(v.x*v.x + v.y*v.y + v.z*v.z)
}

vec3_normalize :: proc(v: Vec3) -> Vec3 {
    len := vec3_length(v)
    return Vec3{v.x / len, v.y / len, v.z / len}
}

vec3_dot :: proc(a, b: Vec3) -> f64 {
    return a.x*b.x + a.y*b.y + a.z*b.z
}

main :: proc() {
    position := Vec3{3.0, 4.0, 0.0}
    direction := Vec3{1.0, 2.0, 2.0}

    fmt.printf("Position: {%.2f, %.2f, %.2f}\n", position.x, position.y, position.z)
    fmt.printf("Length: %.4f\n", vec3_length(position))

    norm := vec3_normalize(direction)
    fmt.printf("Normalized: {%.4f, %.4f, %.4f}\n", norm.x, norm.y, norm.z)
    fmt.printf("Dot product: %.4f\n", vec3_dot(position, direction))
}

No this pointer. No method syntax sugar. vec3_length is a procedure that takes a Vec3 and returns an f64. You can read this code top to bottom and know exactly what it does without looking up class definitions or vtable layouts.

This is deliberate. Odin is built for game developers and systems programmers who care about cache performance and data layout. When your struct is just data and your procedures are just functions, the compiler (and the CPU) can reason about your program more effectively.

Why game developers are paying attention

Odin has features that matter specifically for games and real-time applications:

• SOA (struct of arrays) support is built into the type system, not bolted on
• Context system passes allocators and loggers implicitly without global state
• No hidden allocations -- if memory is allocated, you asked for it
• Explicit error handling through multiple return values, not exceptions

The language targets the same niche as C but refuses to carry C's historical baggage. No preprocessor. No header files. No undefined behavior by design.

For trying Odin before committing to a local setup, an online compiler works well:

• Test struct layouts and procedure signatures interactively
• Experiment with Odin's built-in array programming features
• Share code with other developers without asking them to build the compiler first
• Work through tutorials when you're away from your main dev machine

Try Odin on OneCompiler

OneCompiler's Odin online compiler lets you write and run Odin code immediately. No compiler build step, no nightly release to download. Just code, run, and see the output.

If you've been curious about what a modern C alternative designed for game development actually looks like, give it a shot.