D Online Compiler - Run D Code in Your Browser

D gets described as "a better C++" and honestly, that undersells it. It took the template metaprogramming that makes C++ powerful, stripped out the footguns, and added a garbage collector you can turn off when you need bare-metal control. The result is a systems programming language that's actually pleasant to write.

The problem? Getting a D toolchain set up locally means installing DMD or LDC, configuring DUB, and sorting out platform-specific linker issues. If you just want to test a template or try out D's range-based algorithms, that's a lot of overhead for a 20-line program.

A D online compiler skips all of that. Open a browser tab, write your code, hit run.

D's template system is worth experimenting with

One of D's best features is compile-time function evaluation and its template system. Unlike C++ templates that produce error novels, D templates are readable and debuggable. Here's a quick example using D's ranges and algorithm library:

import std.stdio;
import std.algorithm;
import std.range;
import std.conv;

void main() {
    // Generate squares of even numbers from 1 to 20
    auto result = iota(1, 21)
        .filter!(n => n % 2 == 0)
        .map!(n => n ^^ 2)
        .array;

    writeln("Squares of even numbers: ", result);

    // Compile-time computation
    enum factorial = {
        int result = 1;
        foreach (i; 1 .. 11)
            result *= i;
        return result;
    }();

    writeln("10! computed at compile time: ", factorial);
}

That enum factorial block runs entirely at compile time. No runtime cost. This is the kind of thing that's hard to appreciate until you actually run it yourself and see that the compiler just folds it into a constant.

Why try D in a browser?

D occupies an interesting space. It has the performance of C++ with the ergonomics closer to Python or Ruby when you want it. The optional GC means you can write high-level code for prototyping, then drop down to @nogc for performance-critical paths.

But D's community is smaller than Rust or Go. Finding local help with toolchain issues takes longer. An online compiler removes that barrier entirely -- you get a working D environment in seconds regardless of your OS.

A few situations where a D online compiler makes sense:

• Testing how D's ranges compose before committing to a design
• Exploring static if, mixin, and other metaprogramming features
• Sharing code snippets with other developers without asking them to install anything
• Working through D tutorials or the "Programming in D" book interactively

Try D on OneCompiler

OneCompiler's D online compiler gives you a clean editor with immediate execution. No sign-up wall, no project scaffolding. Paste your code, run it, share the link if someone else needs to see it.

If you've been curious about D but didn't want to set up a local toolchain just to kick the tires, this is the fastest way in.