# The playground

> A scratchpad that runs six languages with no account and no setup - what it saves, what the two shortcuts do, and the ceilings your program runs under.

Source: https://www.revquix.com/docs/projects/the-playground
Last verified: 2026-09-04

---

[The playground](https://www.revquix.com/playground) is a single file, an editor and a Run button.
No account, no project, no setup - it is the fastest way to run something on Revquix, and the right
place for "does this actually work?"

Reach it from the command palette with `⌘K`.

## Six languages

**Java**, **C++**, **Python**, **JavaScript**, **TypeScript** and **SQL** (SQLite).

> **Note** - Java's file is called Main
>
> So `public class Main` is the shape every tutorial you will read assumes. The playground does not
> actually enforce the class name - a `public class Solution` runs fine - but matching what you have
> read saves confusion.

Switching language keeps what you wrote in the one you left.

## Giving your program input

The **Input** panel below the editor is standard input. It sits collapsed as a single row until you
put something in it, so it costs no space when you are not using it.

It is not an optional extra: practice problems and interview questions read from stdin almost
without exception.

> **Warning** - SQL is the exception
>
> The SQL runner has no standard input - the query itself is the input. The panel does not apply
> there.

## Two shortcuts

|            |                                       |
| ---------- | ------------------------------------- |
| **Run**    | `⌘ ↵` - `Ctrl ↵` on Windows and Linux |
| **Format** | `⌘ S` - `Ctrl S`                      |

> **Note** - ⌘S formats, it does not save
>
> There is nothing to save - your work is already being kept as you type. Binding the muscle-memory
> key to formatting beats letting the browser open a Save dialog over the editor.

Pasted code is formatted for you on the way in.

## Your work is kept

Every keystroke is stored in **your browser**, per language. Refresh, close the tab, come back
tomorrow - it is there.

Signed in, a copy is also kept on your account, which is what carries your work between devices.

> **Note** - A newer server copy is offered, never applied
>
> If your account holds a newer file than the one on screen, a line appears offering it. Nothing
> changes until you press something - replacing what you may be typing in, because a timestamp said
> so, is how autosave destroys work.

## On a phone

The layout is replaced rather than squeezed: the editor goes full width, the output rises as a sheet
when a run finishes, the Run bar pins to the bottom, and a row of programming symbols appears above
the keyboard - because the characters this is for are two keyboard-switches deep otherwise.

## The ceilings

Same runner the rest of Revquix uses, so the same limits:

- **Your code** - up to 64 KB.
- **Input** - up to 16 KB.
- **Output** - capped. A program that goes past it is **stopped**, not trimmed, and the result says
  so rather than handing you a truncated answer that looks complete.
- **Time** - a few seconds per run. An infinite loop ends as a timeout.

There is also a **daily run allowance**, shared with Projects and Practice. Signed out it is smaller,
and you may be asked to complete a quick "are you human" check before your first run.

## When you need more than one file

The playground is deliberately one file. A file tree, dependencies between files, tests, AI assist
and GitHub push are [projects](https://www.revquix.com/docs/projects/what-is-a-project).

## Related

- [Sharing a snippet](https://www.revquix.com/docs/projects/sharing-a-snippet) - Turning what you wrote into a link.

- [What a project is](https://www.revquix.com/docs/projects/what-is-a-project) - When one file stops being enough.

- [Practice](https://www.revquix.com/docs/practice/what-practice-is) - Code with a judge attached.