> ## 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. # How to Host FastAPI Applications > Learn how to create and host FastAPI applications on Square Cloud. export const PortNote = ({lang}) => { const t = { 'en': { q: 'What port should I use for my server?', a1: <>You should use port 80 for your server. Port 80 is the default port for HTTP traffic, which is handled by Square Cloud to route it to 443, HTTPS, for a secure connection., a2: 'Make sure to configure it before compressing and uploading your project.' }, 'pt-br': { q: 'Qual porta devo usar para o meu servidor?', a1: <>Você deve usar a porta 80 para o seu servidor. A porta 80 é a porta padrão para tráfego HTTP; a Square Cloud a encaminha para 443 (HTTPS) para estabelecer uma conexão segura., a2: 'Certifique-se de configurá-la antes de compactar e enviar seu projeto.' }, 'es': { q: '¿Qué puerto debo usar para mi servidor?', a1: <>Debes usar el puerto 80 para tu servidor. El puerto 80 es el puerto predeterminado para el tráfico HTTP; Square Cloud lo redirige al 443 (HTTPS) para establecer una conexión segura., a2: 'Asegúrate de configurarlo antes de comprimir y subir tu proyecto.' }, 'fr': { q: 'Quel port dois-je utiliser pour mon serveur ?', a1: <>Vous devez utiliser le port 80 pour votre serveur. Le port 80 est le port par défaut du trafic HTTP ; Square Cloud le redirige vers le port 443 (HTTPS) pour établir une connexion sécurisée., a2: "Assurez-vous de le configurer avant de compresser et d'envoyer votre projet." }, 'de': { q: 'Welchen Port sollte ich für meinen Server verwenden?', a1: <>Verwenden Sie Port 80 für Ihren Server. Port 80 ist der Standardport für HTTP-Traffic; Square Cloud leitet ihn für eine sichere Verbindung an Port 443 (HTTPS) weiter., a2: 'Stellen Sie sicher, dass Sie ihn konfigurieren, bevor Sie Ihr Projekt komprimieren und hochladen.' }, 'it': { q: 'Quale porta devo usare per il mio server?', a1: <>Devi usare la porta 80 per il tuo server. La porta 80 è la porta predefinita per il traffico HTTP; Square Cloud la instrada verso la 443 (HTTPS) per stabilire una connessione sicura., a2: 'Assicurati di configurarla prima di comprimere e caricare il tuo progetto.' }, 'ja': { q: 'サーバーにはどのポートを使えばよいですか？', a1: <>サーバーにはポート80を使用してください。ポート80はHTTPトラフィックのデフォルトポートで、Square Cloudが安全な接続のために443（HTTPS）へルーティングします。, a2: 'プロジェクトを圧縮してアップロードする前に、必ず設定してください。' }, 'zh': { q: '我的服务器应该使用哪个端口？', a1: <>您的服务器应使用端口 80。端口 80 是 HTTP 流量的默认端口，Square Cloud 会将其路由到 443（HTTPS）以建立安全连接。, a2: '请务必在压缩并上传项目之前完成配置。' } }; const c = t[lang] || t['en']; return {c.q}
{c.a1}
{c.a2} ; }; export const PyDepFiles = ({lang}) => { const desc = { "en": { requirements: "Standard file used in Python projects to list all the external libraries and dependencies that your project needs. Each line in this file specifies a package to be installed using pip, the Python package manager.", pyproject: "A modern configuration file for Python projects that can specify build system requirements and project metadata. It is used by tools like Poetry to manage dependencies and packaging." }, "pt-br": { requirements: "Arquivo padrão usado em projetos Python para listar todas as bibliotecas externas e dependências necessárias para o seu projeto. Cada linha neste arquivo especifica um pacote a ser instalado usando o pip, o gerenciador de pacotes do Python", pyproject: "Um arquivo de configuração moderno para projetos Python que permite especificar requisitos do sistema de compilação e metadados do projeto. É utilizado por ferramentas como o Poetry para gerenciar dependências e empacotamento." }, "es": { requirements: "Archivo estándar usado en proyectos Python para listar todas las bibliotecas externas y dependencias que tu proyecto necesita. Cada línea de este archivo especifica un paquete que se instalará usando pip, el gestor de paquetes de Python.", pyproject: "Un archivo de configuración moderno para proyectos Python que permite especificar los requisitos del sistema de compilación y los metadatos del proyecto. Lo utilizan herramientas como Poetry para gestionar dependencias y empaquetado." }, "fr": { requirements: "Fichier standard utilisé dans les projets Python pour lister toutes les bibliothèques externes et dépendances nécessaires à votre projet. Chaque ligne de ce fichier spécifie un paquet à installer avec pip, le gestionnaire de paquets de Python.", pyproject: "Un fichier de configuration moderne pour les projets Python qui permet de spécifier les exigences du système de build et les métadonnées du projet. Il est utilisé par des outils comme Poetry pour gérer les dépendances et le packaging." }, "de": { requirements: "Standarddatei in Python-Projekten, die alle externen Bibliotheken und Abhängigkeiten Ihres Projekts auflistet. Jede Zeile dieser Datei gibt ein Paket an, das mit pip, dem Paketmanager von Python, installiert wird.", pyproject: "Eine moderne Konfigurationsdatei für Python-Projekte, die Build-System-Anforderungen und Projektmetadaten festlegen kann. Sie wird von Tools wie Poetry zur Verwaltung von Abhängigkeiten und Packaging verwendet." }, "it": { requirements: "File standard usato nei progetti Python per elencare tutte le librerie esterne e le dipendenze necessarie al tuo progetto. Ogni riga di questo file specifica un pacchetto da installare con pip, il gestore di pacchetti di Python.", pyproject: "Un file di configurazione moderno per i progetti Python che consente di specificare i requisiti del sistema di build e i metadati del progetto. È utilizzato da strumenti come Poetry per gestire dipendenze e packaging." }, "ja": { requirements: "Python プロジェクトで、必要な外部ライブラリと依存関係をすべて列挙するための標準ファイルです。このファイルの各行は、Python のパッケージマネージャーである pip でインストールするパッケージを指定します。", pyproject: "ビルドシステムの要件やプロジェクトのメタデータを指定できる、Python プロジェクト向けのモダンな設定ファイルです。Poetry などのツールが依存関係とパッケージングの管理に使用します。" }, "zh": { requirements: "Python 项目中用于列出项目所需的所有外部库和依赖项的标准文件。文件中的每一行指定一个通过 pip（Python 的包管理器）安装的包。", pyproject: "Python 项目的现代配置文件，可指定构建系统要求和项目元数据。Poetry 等工具使用它来管理依赖项和打包。" } }; const d = desc[lang] || desc.en; return {d.requirements} {d.pyproject} ; }; export const RecommendedPlan = ({lang, plan, tier, cpu, appType}) => { const siteLang = lang === 'pt-br' ? 'pt-br' : 'en'; const url = `https://squarecloud.app/${siteLang}/pay?plan=${plan.toLowerCase()}&tier=${tier}`; const proUrl = `https://squarecloud.app/${siteLang}/pay?plan=pro`; const notes = { 'en': Wondering how much RAM and CPU your plan needs to host {appType}?
Don't worry, we're here to help. Our {plan} plan offers {tier}GB of RAM and {cpu}vCPU, which should be sufficient for most {appType}. However, if you are working on a larger project and seeking extra stability, we recommend considering our Pro plan. With additional resources, you can maintain stability even during demand spikes. To purchase, simply click here. , 'pt-br': Está se perguntando quanta RAM e CPU seu plano precisa para hospedar {appType}?
Não se preocupe, estamos aqui para ajudar. Nosso plano {plan} oferece {tier}GB de RAM e {cpu}vCPU, o que deve ser suficiente para a maioria dos {appType}. No entanto, se você estiver trabalhando em um projeto maior e precisar de mais estabilidade, recomendamos considerar nosso plano Pro. Com recursos adicionais, você pode manter a estabilidade mesmo durante picos de demanda. Para comprar, basta clicar aqui. , 'es': ¿Te preguntas cuánta RAM y CPU necesita tu plan para alojar {appType}?
No te preocupes, estamos aquí para ayudarte. Nuestro plan {plan} ofrece {tier}GB de RAM y {cpu}vCPU, lo que debería ser suficiente para la mayoría de {appType}. Sin embargo, si estás trabajando en un proyecto más grande y buscas mayor estabilidad, te recomendamos considerar nuestro plan Pro. Con recursos adicionales, puedes mantener la estabilidad incluso durante picos de demanda. Para comprarlo, simplemente haz clic aquí. , 'fr': Vous vous demandez combien de RAM et de CPU votre plan doit offrir pour héberger {appType} ?
Pas d'inquiétude, nous sommes là pour vous aider. Notre plan {plan} offre {tier} Go de RAM et {cpu} vCPU, ce qui devrait suffire pour la plupart des {appType}. Cependant, si vous travaillez sur un projet plus important et recherchez une stabilité accrue, nous vous recommandons notre plan Pro. Avec des ressources supplémentaires, vous conservez la stabilité même lors des pics de demande. Pour l'acheter, cliquez simplement ici. , 'de': Sie fragen sich, wie viel RAM und CPU Ihr Plan zum Hosten von {appType} benötigt?
Keine Sorge, wir helfen Ihnen gerne. Unser {plan}-Plan bietet {tier} GB RAM und {cpu} vCPU, was für die meisten {appType} ausreichen sollte. Wenn Sie jedoch an einem größeren Projekt arbeiten und zusätzliche Stabilität benötigen, empfehlen wir unseren Pro-Plan. Mit zusätzlichen Ressourcen bleibt Ihre Anwendung auch bei Lastspitzen stabil. Zum Kauf klicken Sie einfach hier. , 'it': Ti stai chiedendo quanta RAM e CPU serve al tuo piano per ospitare {appType}?
Non preoccuparti, siamo qui per aiutarti. Il nostro piano {plan} offre {tier}GB di RAM e {cpu}vCPU, che dovrebbero essere sufficienti per la maggior parte di {appType}. Tuttavia, se stai lavorando a un progetto più grande e cerchi maggiore stabilità, ti consigliamo il nostro piano Pro. Con risorse aggiuntive puoi mantenere la stabilità anche durante i picchi di richieste. Per acquistarlo, fai clic qui. , 'ja': {appType}のホスティングに必要なRAMとCPUの容量が気になりますか？
ご安心ください。私たちがサポートします。 {plan}プランは{tier}GBのRAMと{cpu}vCPUを提供しており、ほとんどの{appType}には十分です。 より大規模なプロジェクトでさらなる安定性を求める場合は、Proプランをおすすめします。追加リソースにより、需要のピーク時でも安定性を維持できます。 ご購入はこちらをクリックしてください。 , 'zh': 想知道托管{appType}需要多少 RAM 和 CPU 吗？
别担心，我们来帮您。 我们的 {plan} 套餐提供 {tier}GB RAM 和 {cpu}vCPU，对大多数{appType}来说已经足够。 如果您的项目规模更大、需要更高的稳定性，我们推荐 Pro 套餐。借助额外资源，即使在需求高峰期也能保持稳定。 点击这里即可购买。 }; return notes[lang] || notes['en']; }; export const appType_0 = "a FastAPI application" ## Introduction To develop and host {appType_0} on Square Cloud, it's essential to follow a structured sequence of configurations and prerequisites. This technical guide will cover the entire process, from initial setup to production deployment. ### Prerequisites * **Square Cloud Account**: Register through the [signup page](https://squarecloud.app/en/signup) using your email. * **Active Paid Plan**: Ensures dedicated resources and optimized performance for your application. Check our [available plans](https://squarecloud.app/en/pricing) and choose the most suitable for your needs. ## Creating project To create a FastAPI application, you need to have Python and pip installed on your system before following the steps. ### Installing library With Python and pip installed, create your FastAPI project. First, install the required dependencies: ```bash Terminal theme={null} pip install fastapi uvicorn ``` ### Developing project Create a Python file (for example, `main.py`) and add the following code to implement a basic FastAPI application: ```python main.py theme={null} # Import the FastAPI class and the uvicorn ASGI server from fastapi import FastAPI import uvicorn # Create an instance of the FastAPI class app = FastAPI() # Define a route for the root URL (/) that returns 'Hello, World!' @app.get("/") def hello_world(): return {"message": "Hello, World!"} # Check if this script is being run directly (not imported as a module) if __name__ == "__main__": # Run the FastAPI application on host 0.0.0.0 (all available network interfaces) and port 80 uvicorn.run(app, host="0.0.0.0", port=80) ``` In the code above, we implement a simple route that returns "Hello, World!" when accessed. The application is configured to run on port 80, which is the default HTTP port. Next, we need to create our dependencies file. In Python we have requirements.txt or a pyproject.toml ## Choosing a production server Uvicorn is already an ASGI server suitable for production, so no additional WSGI server is required. On Square Cloud, instead of running `python main.py`, set the `START` field in your configuration file to launch Uvicorn directly: ```systemd squarecloud.config theme={null} START=python -m uvicorn main:app --host 0.0.0.0 --port 80 ``` For applications with higher traffic, you can add extra Uvicorn workers, e.g. `START=python -m uvicorn main:app --host 0.0.0.0 --port 80 --workers 4`. ## Deploying After preparing your project files, you can now upload them to Square Cloud and host your project. To do so, create a ZIP file containing all your project files. ### Via dashboard Access the [upload page](https://squarecloud.app/en/dashboard/new) and upload your project zip file. After uploading your zip, you will need to configure the name, main file or runtime environment and other settings for your project.\ If you are uploading a web project, make sure to select "Web Publication" and set a subdomain to your project. Finally, click on the "Deploy" button to host your project on Square Cloud.\ After deployment, you can monitor your project's status and logs from the dashboard. Uploading application to Square Cloud Your first deploy usually takes less than a minute. In the [dashboard](https://squarecloud.app/en/dashboard), wait for your application status to show as running and check the logs for any startup errors.\ If you deployed a website or API, open `https://.squareweb.app` in your browser — you should see your application responding. If you deployed a bot, send it a command to confirm it is online. App not starting? See the [Troubleshooting guide](/en/platform/troubleshooting/app-wont-start) for the most common causes and fixes. ### Via CLI To use this method, you need to create a config file named `squarecloud.app` in the root directory of your project. This file will contain the necessary configuration for your project. Learn how to create the `squarecloud.app` configuration file that defines your application's environment. First, you need to have the CLI installed in your environment. If you don't have it yet, run the following command in your terminal: ``` npm install -g @squarecloud/cli ``` If you already have it, we recommend updating it. To do this, run the following command in your terminal: ```bash theme={null} squarecloud update ``` ```bash theme={null} curl -fsSL https://cli.squarecloud.app/install | bash ``` Now, to authenticate and use other CLI commands, you will find your authorization key [here](https://squarecloud.app/en/account/security) by clicking on "Request API Key". After obtaining your authorization key, run the following command: ```bash theme={null} squarecloud auth login ``` Finally, to deploy your application to Square Cloud using the CLI, you need to run the following command: ```bash theme={null} squarecloud upload ``` Or if you created the zip manually, you can use: ```bash theme={null} squarecloud upload --file ``` Your first deploy usually takes less than a minute. Check your application status and logs directly from the terminal: ```bash theme={null} squarecloud app status squarecloud app logs ``` If you deployed a website or API, open `https://.squareweb.app` in your browser — you should see your application responding. If you deployed a bot, send it a command to confirm it is online. App not starting? See the [Troubleshooting guide](/en/platform/troubleshooting/app-wont-start) for the most common causes and fixes. ## Troubleshooting ### Custom Domain To use a custom domain (e.g., `mysite.com`) instead of the default URL `mysite.squareweb.app`, you need the **Standard plan or higher**. The subdomain is defined by the **SUBDOMAIN** field in the configuration file. ### Minimum RAM Requirements **Minimum: 512MB RAM** for simple websites/APIs. For sites with frameworks (Next.JS, React, Vue, Angular, etc.), we always recommend **at least 1GB RAM**. For larger applications, allocate more RAM to prevent the application from running out of memory and crashing. ### Could not find this site. Check if the **subdomain/domain** matches what's configured in the **SUBDOMAIN** field or in the **custom domain settings**. If you just uploaded the site, wait up to **60 seconds** for Square to enable **first access**. ### Site took too long to respond... Check if you correctly configured **port 80** and **host 0.0.0.0** in the application. We recommend using Square's forced environment variables: **PORT** and **HOST** from the `.env` file. ## Additional resources For more detailed information about FastAPI and its advanced tools, visit the [official FastAPI documentation](https://fastapi.tiangolo.com/). There you will find in-depth technical guides, specialized tutorials, and full API documentation to make the most of FastAPI's features. ## Contact us If you continue facing **technical difficulties**, our **specialized support team** is available to assist you. [**Contact us**](https://squarecloud.app/en/support) and we'll be happy to help you resolve any issue — support quality is a big part of why developers rate Square Cloud [**4.9/5 across 402 reviews**](https://www.trustpilot.com/review/squarecloud.app) on Google and Trustpilot.