Free Online Angular Modern Compiler

Quick overview: Angular (Modern)

Use the editor above to run a small Angular (Modern) idea without setting up a project first. This page loads Zone.js and reflect-metadata, then runs the Angular sample in the page preview instead of a Piston language container. Run it. Read the output. Then change one thing, because the fastest debugging session is usually the one with the fewest moving parts.

We built this page for short checks: template binding checks, component demos, form snippets, and short teaching examples. It is deliberately narrower than a local environment, and that is the point; when a snippet is only twenty lines long, a full toolchain can get in the way of the question you actually have.

Modern Angular has moved toward standalone components and signals, but older examples still assume NgModules and decorator metadata. For checking a binding or template expression, this page is plenty; for routing, SSR, or dependency injection architecture, open a real Angular workspace.

What happens when Run fires

The loop is intentionally plain. Write code in the main editor, provide STDIN or arguments if the page exposes those controls, and press Run.

The page packages the source and input, sends them to the configured runner or preview frame, and prints standard output plus errors in the output area. Short path. Useful signal.

When something fails, read the first error before changing the whole snippet; many compiler messages are noisy at the bottom but precise near the top, especially when a missing bracket causes a chain of follow-up complaints.

If the first run succeeds, resist the urge to paste the whole project next. Add one feature, one input case, or one Angular (Modern) construct at a time, because a runner like this is best at showing the exact moment a simple idea stops being simple.

Try it small

The saved example below is intentionally left unchanged. Run it once as written, then make a small edit and run it again; that gives you a known-good baseline before you test your own idea.

<!-- Template -->
<div class="card">
    <h1>{{ title }}</h1>
    <p>Count: {{ count }}</p>
    <button (click)="increment()">Increment</button>
    <ul>
        <li *ngFor="let task of tasks">{{ task }}</li>
    </ul>
</div>

// Component class body
constructor() {
    this.title = "Angular 15 Playground";
    this.count = 0;
    this.tasks = ["Plan UI", "Wire data", "Ship"];
}

increment() {
    this.count += 1;
}

After the sample works, try one edge case that exercises the page's limits. Modern Angular has moved toward standalone components and signals, but older examples still assume NgModules and decorator metadata. That single change often teaches more than pasting a large program and trying to guess which part failed.

Caveats before use

This page is strongest when the problem is small and visible. It is weakest when the problem depends on SSR behavior, full CLI builds, router-heavy apps, and package-version investigations. Two caveats.

• Do not paste secrets, tokens, private URLs, or customer data.
• The environment is intentionally constrained, so a snippet that works here still deserves a local check when compiler flags, packages, server state, or exact versions matter.
• Timeouts are normal for runaway loops. They protect the shared runner.

We deliberately keep the sandbox narrow. That makes the output easier to trust for template binding checks, component demos, form snippets, and short teaching examples, while making it clear when you have outgrown the page.

One practical test: if you cannot explain the snippet in one sentence, split it. The runner is happiest when each run answers a single question, and you will be happier too when the error message points at one idea instead of a pile of guesses.

Where it fits

Three uses come up often: checking syntax while reading docs, reducing a bug report to something another person can run, and trying a small variation before editing a larger project.

For Angular (Modern), the best examples are boring in a useful way. They fit on one screen, they name the input, and they show the exact output you expected or the exact error you got.

A good habit is to keep one saved version that passes, then make the risky change in a copy. When the output changes, you know which line caused it; when it does not, you have learned that the bug probably lives in setup, data, or assumptions rather than the syntax itself.

Questions people actually ask

Only a few questions belong here. The goal is to answer the mistakes that actually interrupt a small Angular (Modern) run, not to pad the page.

Further reading

Reference pages are better than folklore when an error message gets specific. Start with official docs, then use tutorials for context once the rule is clear.

• Angular documentation
• Angular components
• Angular signals

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