> ## Documentation Index > Fetch the complete documentation index at: https://docs.squarecloud.app/llms.txt > Use this file to discover all available pages before exploring further. # squarecloud.app Configuration File Reference > Configure your app with the squarecloud.app file: MAIN, MEMORY, VERSION, DISPLAY_NAME, RUNTIME, START, SUBDOMAIN and AUTORESTART, with bot and site examples. ## What is the configuration file? The configuration file tells Square Cloud how to run your application: which file to start, how much memory to reserve, which runtime version to use and, for a website, which subdomain to publish. It is a plain text file with one `KEY=VALUE` pair per line. ```systemd squarecloud.app theme={"system"} MAIN=index.js MEMORY=512 VERSION=recommended DISPLAY_NAME=My first app ``` ## Creating the configuration file Create a file named `squarecloud.app` or `squarecloud.config` at the root of your project. Both names work the same way. When you upload a zip, the file must sit at the top level of the zip, not inside a subfolder, or the deploy fails with `MISSING_CONFIG`. On **macOS**, we recommend the `squarecloud.config` name. The [VS Code extension](/en/vscode-extension/features#config-file-intellisense) autocompletes every key below and underlines invalid values as you type. ## Configuration parameters `MEMORY`, `VERSION` and `DISPLAY_NAME` are always required. `MAIN` is required unless you set `RUNTIME`. | Parameter | Required | Editable after deploy | Limit | Purpose | | - | - | - | - | - | | [`MAIN`](#main) | Unless `RUNTIME` is set | No | 32 characters | File that starts the application. | | [`MEMORY`](#memory) | Yes | Yes | Your plan's free RAM | RAM reserved for the application, in MB. | | [`VERSION`](#version) | Yes | No | `recommended` or `latest` | Runtime version. | | [`DISPLAY_NAME`](#display_name) | Yes | Yes | 32 characters | Name shown in the dashboard. | | [`DESCRIPTION`](#description) | No | Yes | 280 characters | Short description. | | [`AUTORESTART`](#autorestart) | No | Yes | `true` or `false` | Restart the application after a crash. | | [`SUBDOMAIN`](#subdomain) | No | Only on websites | 63 characters | Publishes the application as a website. | | [`RUNTIME`](#runtime) | No | No | See the table | Runtime, when `MAIN` can't tell it. | | [`START`](#start) | No | Yes | 256 characters | Custom start command. | Editable parameters can be changed in the dashboard after the deploy. Changing a non-editable parameter requires uploading the application again. ### MAIN The file that starts your application, relative to the project root. ```systemd theme={"system"} MAIN=index.js ``` ```systemd theme={"system"} MAIN=src/bot/main.py ``` * The file extension selects the runtime: `.js` runs on Node.js, `.ts` on TypeScript, `.py` on Python, and so on. * The file must exist in your upload and can't be empty. * Up to 32 characters: letters, digits, `_`, `.`, `/` and `-`, no spaces. A missing `MAIN` (without `RUNTIME`) fails with `MISSING_MAIN`; a file that doesn't exist, has no extension or breaks the rules above fails with `INVALID_MAIN`. ### MEMORY The RAM reserved for your application, in megabytes. It also sets your application's vCPUs and bandwidth. ```systemd theme={"system"} MEMORY=512 ``` The value must be at least the [minimum for your project type](/en/platform/limitations-and-restrictions#minimum-resource-requirements), and no more than the RAM your plan still has free. Otherwise the deploy fails with `INSUFFICIENT_MEMORY`. ### VERSION The runtime version: `recommended` or `latest`. Any other value, including an exact version number, fails the deploy with `INVALID_VERSION`. ```systemd theme={"system"} VERSION=recommended ``` Use `recommended` unless you need a feature that only the newest release has. The versions behind each value are listed in the [runtime versions table](/en/runtimes/introduction#versions). ### DISPLAY\_NAME The name shown in the dashboard, the CLI and the API. ```systemd theme={"system"} DISPLAY_NAME=Admin bot ``` Up to 32 characters: letters without accents, digits, spaces, `-` and `_`. Anything else, such as accented letters or emoji, fails with `INVALID_DISPLAY_NAME`. ### DESCRIPTION A short description of the application, up to 280 characters (`INVALID_DESCRIPTION` beyond that). ```systemd theme={"system"} DESCRIPTION=This bot helps with your daily tasks. ``` ### AUTORESTART Restarts the application automatically after a crash. Accepts `true` or `false`, and defaults to `false`, so turn it on for bots and anything that must stay online. ```systemd theme={"system"} AUTORESTART=true ``` An automatic restart happens only when all of these are true: * The application exited with status `1`, the usual exit code of an unhandled error in Node.js and Python. * It had been running for at least 60 seconds, so an app that crashes right at boot isn't restarted in a loop. * It hasn't been restarted automatically in the last hour. * The logs don't show an error a restart can't fix: an invalid bot token, a missing module, a syntax or TypeScript type error, or a failed dependency install. A restart keeps the app online through a transient error, but the underlying bug still needs a fix in your code. See also the help center article on [auto restart](https://help.squarecloud.app/en-us/article/how-to-use-auto-restart-on-square-cloud-nmhvh0/). ### SUBDOMAIN Publishes the application as a website at `https://.squareweb.app`. ```systemd theme={"system"} SUBDOMAIN=mysite ``` * Up to 63 characters: letters, digits and hyphens, not starting or ending with a hyphen. The name is stored in lowercase. * A name that is already in use, reserved (such as `admin` or `api`) or invalid fails with `INVALID_SUBDOMAIN`. * A website needs more RAM than a bot: see the [minimum RAM](/en/platform/limitations-and-restrictions#minimum-resource-requirements). * Your server must listen on port `80` and host `0.0.0.0` (see [website doesn't load](/en/platform/troubleshooting/app-wont-start#website-doesnt-load)). Decide at the first upload whether the application is a website. On a website you can change the subdomain later, but you can't remove it (`CANNOT_SET_SUBDOMAIN`). An application deployed without `SUBDOMAIN` can't become a website: upload it again as a new application with `SUBDOMAIN` set. To serve the site on your own domain, see [how to set up your own domain](https://help.squarecloud.app/en-us/article/how-to-set-up-your-own-domain-cnamedns-1fzbrgh/) in the help center. ### RUNTIME Sets the runtime explicitly, instead of deriving it from the extension of `MAIN`. An unknown value fails with `INVALID_RUNTIME`. ```systemd theme={"system"} RUNTIME=nodejs ``` | Runtime | Accepted values | | - | - | | Node.js | `nodejs`, `javascript` | | TypeScript | `typescript` | | Python | `python` | | C# / .NET | `csharp`, `dotnet`, `c#` | | Elixir | `elixir` | | Java | `java` | | Rust | `rust` | | Ruby | `ruby` | | PHP | `php` | | Go | `go`, `golang` | | Static HTML/CSS | `static`, `html` | With `RUNTIME` set you can leave out `MAIN`. In that case, also set `START`: most runtimes start the application by running the `MAIN` file. ### START A custom start command. It replaces the default command, which runs your `MAIN` file. ```systemd theme={"system"} START=npm run start ``` * Up to 256 characters (`INVALID_START` beyond that). * Dependencies are still installed before the command runs. * The command is read from the file on every start, so you can change it by editing `squarecloud.app` in the dashboard and restarting. Only call scripts that exist in your project. `START=npm run build && npm run start`, for example, fails on an Express app without a `build` script in `package.json`. Leave `START` out when the default command is enough. ### ID You don't write this key yourself. After `squarecloud upload`, the Square Cloud CLI adds `ID=` to the file, so later commands such as `squarecloud commit` know [which application to target](/en/cli-reference/quickstart#how-the-cli-finds-your-app). Square Cloud ignores it when deploying. ## Examples ### Bot ```systemd squarecloud.app theme={"system"} MAIN=index.js MEMORY=512 VERSION=recommended DISPLAY_NAME=Robin bot DESCRIPTION=Moderation and music for my server. AUTORESTART=true ``` ### Website or API ```systemd squarecloud.app theme={"system"} MAIN=index.js MEMORY=512 VERSION=recommended DISPLAY_NAME=My site DESCRIPTION=My site is really cool! SUBDOMAIN=mysite AUTORESTART=true ``` The site answers at `https://mysite.squareweb.app`. ### Next.js A framework that needs a build step uses `START`. Here `MAIN` only selects the Node.js runtime, so point it at your actual config file (such as `next.config.mjs`); the build and start scripts come from `package.json`. ```systemd squarecloud.app theme={"system"} MAIN=next.config.js MEMORY=2048 VERSION=recommended DISPLAY_NAME=Nextjs site SUBDOMAIN=nextjs START=npm run build && npm run start AUTORESTART=true ``` ## Next steps Keep tokens and connection strings out of your code and your zip. Choose which files the CLI and VS Code leave out of the upload. Versions, dependency files and how each runtime starts your app. What each deploy error means and how to fix it. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.